View source for Chess

{{Short description|Traditional board game for two players}}
{{About|Western chess|other chess games or other uses|Chess (disambiguation)}}
{{pp-vandalism|small=yes}}
{{Use dmy dates|date=June 2025}}
{{Infobox game
| italic title  = no
| title         = Chess
| image         = ChessSet.jpg
| image_size    = 250px
| image_caption = Part of a [[Staunton chess set]]{{pb}}{{em|Left to right:}} white [[king (chess)|king]], black [[rook (chess)|rook]], black [[queen (chess)|queen]], white [[pawn (chess)|pawn]], black [[knight (chess)|knight]], white [[bishop (chess)|bishop]]
| image_alt     = A selection of white and black chess pieces on a checkered surface.
| years         = {{circa}} 1475 to present<ref>''A World of Chess'', Jean-Louis Cazaux and Rick Knowlton, p. 244</ref> (predecessors {{circa}} 900 years earlier)
| genre         = {{ubl|[[Board game]]|[[Abstract strategy game]]|[[Mind sport]]}}
| players       = 2
| random_chance = None
| skills        = [[Chess strategy|Strategy]], [[Chess tactic|tactics]]
| AKA           = {{ubl|International chess|Western chess}}
}}

'''Chess''' is a [[board game]] for two players. It is an [[abstract strategy game]] that involves [[Perfect information|no hidden information]] and no elements of [[game of chance|chance]]. It is played on a square [[chessboard|board]] consisting of 64 squares arranged in an 8×8 grid. The players, referred to as [[White and Black in chess|"White" and "Black"]], each control sixteen [[Chess piece|pieces]]: one [[king (chess)|king]], one [[queen (chess)|queen]], two [[rook (chess)|rooks]], two [[bishop (chess)|bishops]], two [[knight (chess)|knights]], and eight [[pawn (chess)|pawns]], with each type of piece having a different pattern of movement. An enemy piece may be captured (removed from the board) by moving one's own piece onto the square it occupies. The object of the game is to "[[checkmate]]" (threaten with inescapable capture) the enemy king. There are also several ways a game can end in a [[draw (chess)|draw]].

The recorded history of chess dates back to the emergence of [[chaturanga]] in 7th century [[History of India|India]]. Chaturanga is also thought to be an ancestor of [[Chess variant|similar games]] like {{transliteration|ko|[[Janggi]]}}, {{transliteration|zh|[[xiangqi]]}} and {{transliteration|ja|[[shogi]]}}. After its introduction to [[Persia]], it spread to the Arab world and then to Europe. The modern rules of chess emerged in Europe at the end of the 15th century, becoming standardized and gaining universal acceptance by the end of the 19th century. Today, chess is one of the world's most popular games, with millions of players worldwide.

Organized chess arose in the 19th century. International chess competitions today are governed by [[FIDE]] (''Fédération Internationale des Échecs''), the International Chess Federation. The first universally recognized [[World Chess Champion]], [[Wilhelm Steinitz]], claimed his title in [[World Chess Championship 1886|1886]]; [[Gukesh Dommaraju]] is the current World Champion, having won the title in [[World Chess Championship 2024|2024]].

A large body of [[chess theory]] has developed since the game's inception. Aspects of art are found in [[chess composition]], and chess has in turn influenced [[Western culture]] and [[Chess in the arts|the arts]], and has relevance to other fields such as [[mathematics]], [[computer science]], and [[psychology]]. One of the goals of early [[computer scientists]] was to create a [[chess-playing machine]]. In 1997, [[Deep Blue (chess computer)|Deep Blue]] became the first computer to win a [[Match (chess)|match]] with a reigning World Champion when it [[Deep Blue versus Garry Kasparov|defeated Garry Kasparov]]. The [[chess engine]]s of today are significantly stronger than the best human players and have greatly influenced the development of chess theory. Chess however is [[solving chess|not a solved game]].
{{AN chess|pos=toc}}

==Rules==
{{Main|Rules of chess}}

The rules of chess are published by [[FIDE]] (Fédération Internationale des Échecs; "International Chess Federation"), chess's world governing body, in its ''Handbook''.<ref name="FideLawsOfChess">{{cite web |url=https://handbook.fide.com/chapter/E012023 |title=Fide Laws of Chess taking effect from 1 January 2023 |access-date=1 January 2023 |publisher=FIDE |df=dmy-all |archive-date=1 January 2023 |archive-url=https://web.archive.org/web/20230101083033/https://handbook.fide.com/chapter/E012023 |url-status=live }}</ref> Rules published by [[List of chess federations|national governing bodies]], or by unaffiliated chess organizations, commercial publishers, etc., may differ in some details. FIDE's rules were most recently revised in 2023.

===Setup===
[[File:ChessStartingPosition.jpg|thumb|left|upright=1.0|Setup at the start of a chess game]]
[[Chess set]]s come in a wide variety of styles. The [[Staunton chess set|Staunton pattern]] is the most common, and is usually required for competition.<ref name=fideequip>{{Cite web |title=C. General Rules and Technical Recommendations for Tournaments / 02. Chess Equipment / 01. Standards of Chess Equipment / FIDE Handbook |url=https://handbook.fide.com/chapter/StandardsOfChessEquipment2022 |access-date=2025-01-19 |website=International Chess Federation (FIDE) |language=en}}</ref> Chess sets come with [[chess piece|pieces]] in two colors, referred to as [[White and Black in chess|''white'' and ''black'']], regardless of their actual color; the players controlling the color sets are referred to as ''White'' and ''Black'', respectively. Each set comes with at least the following 16 pieces in both colors: one [[King (chess)|king]], one [[Queen (chess)|queen]], two [[Rook (chess)|rooks]], two [[Bishop (chess)|bishops]], two [[Knight (chess)|knights]], and eight [[Pawn (chess)|pawns]].<ref name=FideLawsOfChess/>

The game is played on a square [[Chessboard|board]] of eight rows (called ''{{chessgloss|ranks}}'') and eight columns (called ''{{chessgloss|files}}''). Although it does not affect gameplay, by convention the 64 squares alternate in color and are referred to as {{em|light}} and {{em|dark}} squares.<ref name="FideLawsOfChess"/><!--FIDE uses "white and black squares" in the citation; new citation needed--->
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{{Chess diagram   
| tright
| 
|rd|nd|bd|qd|kd|bd|nd|rd
|pd|pd|pd|pd|pd|pd|pd|pd
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|pl|pl|pl|pl|pl|pl|pl|pl
|rl|nl|bl|ql|kl|bl|nl|rl
| Initial position: {{em|first row:}} rook, knight, bishop, queen, king, bishop, knight, rook; {{em|second row:}} pawns
}}
To start the game, White's pieces are placed on the first rank in the following order, from left to right: rook, knight, bishop, queen, king, bishop, knight, rook. Pawns are placed on each square of the second rank. Black's position mirrors White's, with equivalent pieces on every file.<ref name="FideLawsOfChess"/> The board is oriented so that the right-hand corner nearest each player is a light square; as a result the white queen always starts on a light square, while the black queen starts on a dark square. This may be remembered by the phrases "white on the right" and "queen on her color".<ref>{{harvp|Hooper|Whyld|1992|p=47}}</ref>

In competitions, the piece colors are allocated to players by the organizers. In informal games, colors may be decided either by mutual agreement, or randomly, for example by a coin toss, or by one player concealing a white pawn in one hand and a black pawn in the other and having the opponent choose.{{citation needed|date=January 2025}}

===Movement===
White moves first, after which players alternate turns. One piece is moved per turn (except when [[castling]], during which two pieces are moved). In the diagrams, dots mark the squares to which each type of piece can move if unoccupied by friendly pieces and there are no intervening piece(s) of either color (except the knight, which leaps over any intervening pieces). With the sole exception of ''[[en passant]]'', a piece captures an enemy piece by moving to the square it occupies, removing it from play and taking its place. The pawn is the only piece that does not capture the way it moves, and it is the only piece that moves and captures in only one direction (forwards from the player's perspective). A piece is said to ''control'' empty squares on which it could capture, ''attack'' squares with enemy pieces it could capture, and ''defend'' squares with pieces of the same color on which it could recapture. Moving is compulsory; a player may not skip a turn, even when [[zugzwang|having to move is detrimental]].

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{{Chess diagram  
|tright
|Moves of the king
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|  |  |  |  |oo|oo|oo|
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}}
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{{Chess diagram  
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|Moves of a rook
|  |  |  |oo|  |  |  | 
|  |  |  |oo|  |  |  | 
|  |  |  |oo|  |  |  | 
|oo|oo|oo|rl|oo|oo|oo|oo
|  |  |  |oo|  |  |  | 
|  |  |  |oo|  |  |  | 
|  |  |  |oo|  |  |  | 
|  |  |  |oo|  |  |  | 
}}
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{{Chess diagram  
|tright
|Moves of a bishop
|  |  |  |  |  |  |  |oo
|oo|  |  |  |  |  |oo|
|  |oo|  |  |  |oo|  |
|  |  |oo|  |oo|  |  |
|  |  |  |bl|  |  |  |
|  |  |oo|  |oo|  |  |
|  |oo|  |  |  |oo|  |
|oo|  |  |  |  |  |oo|
}}
{{col-end}}
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{{Chess diagram  
|tright
|Moves of a queen
|  |  |  |oo|  |  |  |oo
|oo|  |  |oo|  |  |oo| 
|  |oo|  |oo|  |oo|  | 
|  |  |oo|oo|oo|  |  | 
|oo|oo|oo|ql|oo|oo|oo|oo
|  |  |oo|oo|oo|  |  | 
|  |oo|  |oo|  |oo|  | 
|oo|  |  |oo|  |  |oo| 
}}
{{col-break}}
{{Chess diagram 
|tright
|Moves of a knight
|  |  |  |  |  |  |  | 
|  |  |oo|  |oo|  |  | 
|  |oo|  |  |  |oo|  | 
|  |  |  |nl|  |  |  | 
|  |oo|  |  |  |oo|  | 
|  |  |oo|  |oo|  |  | 
|  |  |  |  |  |  |  | 
|  |  |  |  |  |  |  | 
}}
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{{Chess diagram  
|tright
|Moves of a pawn
|  |  |  |  |  |  |  |
|  |ox|oo|ox|  |  |pd|
|  |  |pl|  |  |xx|xo|xx
|  |  |  |  |  |  |xo| 
|  |oo|  |  |  |  |  |
|ox|oo|ox|  |  |pd|  |
|  |pl|  |  |xx|xo|xx|
|  |  |  |  |  |  |  | 
}}
{{col-end}}
{{clear}}
* The [[king (chess)|king]] moves one square in any direction. There is also a special move called ''[[#Castling|castling]]'' which moves the king and a rook. The king is the most valuable piece—it is illegal to play any move that puts one's king under attack by an opponent piece. A move that attacks the king must be parried immediately; if this cannot be done, the game is lost. (See {{seclink|#Check and checkmate}}.)
* A [[rook (chess)|rook]] can move any number of squares along a rank or file. A rook is involved in the king's castling move.
* A [[bishop (chess)|bishop]] can move any number of squares diagonally.
* A [[queen (chess)|queen]] combines the power of a rook and bishop and can move any number of squares along a rank, file, or diagonal.
* A [[knight (chess)|knight]] moves to any of the closest squares that are not on the same rank, file, or diagonal. (Thus the move forms an "L"-shape: two squares vertically and one square horizontally, or two squares horizontally and one square vertically.) The knight is the only piece that can leap over other pieces.
* A [[pawn (chess)|pawn]] can move forward to the unoccupied square immediately in front of it on the same file, or on its first move it can optionally advance two squares along the same file, provided both squares are unoccupied (diagram dots). A pawn can capture an opponent's piece on a square diagonally in front of it by moving to that square (diagram crosses). It {{em|cannot}} capture a piece while advancing along the same file, nor can it move to either square diagonally in front without capturing. Pawns have two special moves: the [[#Special pawn moves|''en passant'' capture]] and [[#Special pawn moves|promotion]].
{{clear left}}

====Check and checkmate====
{{Main|Check (chess)|l1 = Check|Checkmate}}

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{{Chess diagram small 
|tright
|
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |kd|  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |rl|  |  |  |  |
|  |  |  |  |kl|  |  |
|The black king is in [[Check (chess)|check]] by the rook.
}}
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{{Chess diagram small  
|tright
|
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
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|  |  |  |  |bd|bd|  |kd
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|  |  |  |  |  |  |  |kl
|White is in [[checkmate]], being unable to escape attack by the bishop on f3.
}}
{{col-end}}

When a king is under immediate attack, it is ''in [[Check (chess)|check]]''. A move in response to a check is legal only if it results in a position in which the king is no longer in check. There are three ways to counter a check:
* Capture the checking piece.
* Interpose a piece between the checking piece and the king (possible only if the attacking piece is a queen, rook, or bishop and there is a square between it and the king).
* Move the king to a square where it is not under attack.

The object of the game is to [[checkmate]] the opponent; this occurs when the opponent's king is in check, and there is no legal way to get it out of check. In casual games, it is common to announce "check" when putting the opponent's king in check, but this is not required by the rules of chess and is usually not done in tournaments.<ref>{{Cite book|last=United States Chess Federation.|title=U.S. Chess Federation's official rules of chess|others=Just, Tim., Burg, Daniel B.|year=2003|isbn=0-8129-3559-4|edition=5th|publisher=Random House Puzzles and Games|location=New York|oclc=52859422}}</ref>

====Castling====
{{Main|Castling}}

[[File:ChessCastlingMovie en.svg|thumb|upright=0.95|Examples of [[castling]] ([https://upload.wikimedia.org/wikipedia/commons/5/55/ChessCastlingMovie_en.svg view animation])]]
Kings can ''castle'' once per game. Castling consists of moving the king two squares toward either rook of the same color, and then placing the rook on the square that the king crossed.

Castling is possible only if the following conditions are met:<ref name="FideLawsOfChess"/>
* Neither the king nor the rook has previously moved during the game.
* There are no pieces between the king and the rook.
* The king is not in [[#Check|check]] and does not pass through or finish on a square controlled by an enemy piece.

Castling is still permitted if the rook is under attack, or if the rook crosses an attacked square. 
{{clear left}}

====Special pawn moves====
{{Anchor|en passant}}
{{Main|En passant|Promotion (chess)|l2 = Promotion}}

[[File:ChessPawnSpecialMoves.gif|thumb|right|upright=1.15|Examples of special pawn moves: ({{em|left}}) [[Promotion (chess)|promotion]]; ({{em|right}}) ''[[en passant]]'']]
Pawns have two special moves:
* ''En passant'': when a pawn makes a two-square advance to the same rank as an opponent's pawn on an adjacent file, that pawn can capture it ''en passant'' ("in passing"), moving to one square behind the captured pawn. A pawn can only be captured ''en passant'' on the turn after it makes a two-square advance. In the animated diagram, the black pawn advances two squares from g7 to g5, and the white pawn on f5 takes it ''en passant'', landing on g6.
* ''Promotion'': when a pawn advances to its {{chessgloss|eighth rank|last rank}}, it is ''promoted'' and replaced with the player's choice of a queen, rook, bishop, or knight. Usually, pawns are promoted to queens; choosing another piece is called [[underpromotion]]. In the animated diagram, the c7-pawn is advanced to c8 and promoted to a queen. If the required piece is not available (e.g. a second queen), an inverted rook is sometimes used as a substitute, but this is not recognized in FIDE-sanctioned games.
{{clear left}}

===End of the game===

====Win====
A game can be won in the following ways:
* ''[[Checkmate]]:'' The opposing king is in check and no move can get it out of check. (See {{seclink|#Check and checkmate}}.)
* ''[[Rules of chess#Resigning|Resignation]]:'' A player may resign, conceding the game to the opponent.<ref>{{harvp|Burgess|2000|p=481}}</ref> If, however, the opponent has no way of checkmating the resigned player, this is a draw under FIDE Laws.<ref name="FideLawsOfChess" /> Most tournament players consider it good etiquette to resign in a hopeless position.<ref>{{Cite book |title=The Right Way to Play Chess |edition=2008 revised |author=[[David Pritchard (chess player)|David Brine Pritchard]] |others=Updated by Richard James |publisher=Right Way |date=2008-11-06 |orig-date=1950 |isbn=978-0-7160-2199-5 }}</ref><ref>{{cite web|url=https://www.latimes.com/archives/la-xpm-2001-may-18-cl-64946-story.html|work=[[Los Angeles Times]]|title=Why Grandmasters Rarely Checkmate|date=2001-05-18|access-date=2020-12-03|author=Jack Peters|archive-date=29 December 2020|archive-url=https://web.archive.org/web/20201229221956/https://www.latimes.com/archives/la-xpm-2001-may-18-cl-64946-story.html|url-status=live}}</ref> 
* ''Win on time:'' In games with a [[time control]], a player wins if the opponent runs out of time, even if the opponent has a superior position, as long as the player has a theoretical possibility to checkmate the opponent were the game to continue.
* ''Forfeit:'' A player who cheats, violates the rules, or violates the rules of conduct specified for the particular tournament can be forfeited. Occasionally, both players are forfeited.<ref name="FideLawsOfChess"/>

====Draw====
There are several ways a game can end in a [[Draw (chess)|draw]]:
* ''[[Stalemate]]:'' If the player to move has no legal move, but is not in check, the position is a stalemate, and the game is drawn.
* ''[[Rules of chess#Dead position|Dead position]]:'' If neither player is able to checkmate the other by any legal sequence of moves, the game is drawn. For example, if only the kings are on the board, all other pieces having been captured, checkmate is impossible and the game is drawn by this rule. On the other hand, if each player still has a knight, there is a theoretical albeit highly unlikely possibility of checkmate, so this rule does not apply. The dead position rule supersedes an older rule that referred to "insufficient material", thereby extending it to include other positions in which checkmate is impossible, such as blocked [[Chess endgame#King and pawn endings|pawn endings]] in which the pawns cannot be attacked.
* ''[[Draw by agreement]]:'' In tournament chess, draws are most commonly reached by mutual agreement between the players. The correct procedure is to make a move, to verbally offer the draw, and then to start the opponent's clock. If a draw is offered before making a move, the opponent has the right to ask the player to make a move before making their decision on whether or not to accept the draw offer. Traditionally, players were allowed to agree to a draw at any point in the game, occasionally even without having played a single move. Since the 2000s, efforts have been made to discourage early draws, for example by forbidding draw offers before a certain number of moves have been completed or even forbidding draw offers altogether.
* ''[[Threefold repetition]]:'' This most commonly occurs when neither side is able to avoid repeating moves without incurring a disadvantage. The three occurrences of the position need not occur on consecutive moves for a claim to be valid. The addition of the [[fivefold repetition|fivefold repetition rule]] in 2014 requires the arbiter to intervene immediately and declare the game a draw after five occurrences of the same position, consecutive or otherwise, without requiring a claim by either player. FIDE rules make no mention of [[perpetual check]]; this is merely a specific type of draw by threefold repetition.
* ''[[Fifty-move rule]]:'' If during the previous 50 moves no pawn has been moved and no capture has been made, either player can claim a draw. The addition of the [[seventy-five-move rule]] in 2014 requires the arbiter to intervene and immediately declare the game drawn after 75 moves without a pawn move or capture, without requiring a claim by either player. There are several known endgames in which it is possible to force a mate but it requires more than 50 moves before a pawn move or capture is made; examples include some endgames with [[two knights endgame|two knights against a pawn]] and some [[pawnless chess endgame|pawnless endgames]] such as queen against two bishops. Historically, FIDE has sometimes revised the fifty-move rule to make exceptions for these endgames, but these exceptions have since been repealed. Some [[correspondence chess]] organizations do not enforce the fifty-move rule.{{refn|The fifty-move rule is not applied at FICGS.<ref>{{cite web |url=http://www.ficgs.com/membership.html#chess |title=50 moves rules |access-date=1 December 2009 |publisher=FICGS |url-status=live |archive-url=https://web.archive.org/web/20100209034210/http://www.ficgs.com/membership.html#chess |archive-date=9 February 2010}}</ref>|group=note}}
* ''Draw on time:'' In games with a [[time control]], the game is drawn if a player is out of time but no sequence of legal moves would allow the opponent to checkmate the player.<ref name="FideLawsOfChess"/>
* ''Draw by resignation:'' Under FIDE Laws, a game is drawn if a player resigns but no sequence of legal moves would allow the opponent to checkmate that player.<ref name="FideLawsOfChess" />

{{col-begin|width=auto; float:left; clear:left}}
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{{Chess diagram small  
|tleft
|
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |ql|  |  |  |  |
|kd|  |  |  |  |  |  |
|  |  |kl|  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
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|Black (to move) is not in check and has no legal move. The result is [[stalemate]].
}}
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{{Chess diagram small 
|tleft
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|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |kd|  |  |
|  |  |  |  |bl|  |  |
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|A dead position; White's king and bishop are insufficient to deliver [[checkmate]].
}}
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{{Chess diagram small 
|tleft
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|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |kd|  |  |  |
|ox|pd|ox|ox|pd|ox|ox|pd
|xx|pl|xx|xx|pl|xx|xx|pl
|  |  |  |kl|  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|Also a dead position; neither king can capture the other's pawns in order to promote a pawn and give checkmate.
}}
{{col-end}}
{{clear}}

===Time control===
{{Multiple image
| image1            = DGT 2010 digital chess clock.ajb.jpg
| image2            = Garde Schachuhr 1.jpg
| perrow            = 2/1
| total_width       = 400
| caption1          = 
| footer            = Typical digital and analog chess clocks
| caption_align     = center
| footer_align      = center
}}
In competition, chess games are played with a [[time control]]. Time controls are generally divided into categories based on the amount of time given to each player, which range from classical time controls, which allot about 2 hours or more to each player and which can take upwards of seven hours (even longer if [[adjournment (chess)|adjournments]] are permitted), to [[bullet chess]], in which players receive less than three minutes each. Between these are [[rapid chess]] (ten to sixty minutes per player) and [[blitz chess]] (three to ten minutes). Non-classical chess is sometimes referred to as [[fast chess]].

Time is controlled using a [[chess clock]] with two displays, one for each player's remaining time. Analog chess clocks have been largely replaced by digital clocks, which allow for time controls with increments.

There are some aspects unique to online chess. A [[premove]] allows a player to submit a move on the opponent's turn, which gets played automatically if possible using little to no time. Premoves, alongside the relative ease of digital inputs, make [[ultrabullet|faster time controls]] feasible online.

Time controls are also enforced in [[correspondence chess]] competitions. A typical time control is 50 days for every 10 moves. Time is usually allotted per move in online correspondence chess.

==Notation==
{{Main|Algebraic notation (chess)|l1 = Algebraic notation}}

Historically, many different [[chess notation|notation]] systems have been used to record chess moves; the standard system today is short-form [[Algebraic notation (chess)|algebraic notation]].{{refn|See paragraph "C. Algebraic notation" in FIDE Laws of Chess<ref name="FideLawsOfChess"/>}} In this system, files are labeled ''a'' through ''h'' and ranks are labeled ''1'' through ''8''. Squares are identified by the file and rank they occur on; '''g3''' is the square on the g file and the third rank. In English, the piece notations are: ''K'' (king), ''Q'' (queen), ''R'' (rook), ''B'' (bishop), and ''N'' (knight; N is used to avoid confusion with king). Different initials are used in other languages. Moves are recorded as follows:
:{{em|notation of piece moved}} – {{em|destination square}}

[[File:SCD algebraic notation.svg|frame|Square names in [[Algebraic notation (chess)|algebraic chess notation]]]]
For example, Qg5 means "queen moves to g5". Pawns have no letter initials; e4 simply means "pawn moves to e4". When multiple moves could be rendered the same way, the file or rank from which the piece moved is added to resolve ambiguity (e.g. Ngf3 means "knight from the g-file moves to the square f3"; R1e2 means "rook on the first rank moves to e2"). If a move may be disambiguated by rank or file, it is done by file, and in the rare case that both are needed, squares are listed normally (e.g. Qh4xe1).

If the move is a capture, "x" is usually inserted before the destination square, thus Bxf3 means "bishop captures on f3". When a pawn makes a capture, the file from which the pawn departed is often listed even when no disambiguation is necessary; for example, exd5 ("pawn on the e-file captures on d5").

If a pawn moves to its last rank, achieving promotion, the piece chosen is indicated after the move (for example, e1=Q or e1Q). Castling is indicated by the special notations 0-0 for {{chessgloss|kingside}} castling and 0-0-0 for {{chessgloss|queenside}} castling. A move that places the opponent's king in check usually has the notation "+" suffixed. Checkmate can be indicated by suffixing "#". At the end of the game, "1–0" means White won, "0–1" means Black won, and "½–½" indicates a draw.<ref name="FideLawsOfChess"/> Chess moves can be annotated with [[Chess annotation symbols|punctuation marks and other symbols]]. For example: "!" indicates a good move; "!!" an excellent move; "?" a mistake; "??" a blunder; "!?" an interesting move that may not be best; or "?!" a dubious move not easily refuted.<ref>{{harvp|Hooper|Whyld|1992|p=92}}</ref>

[[File:Scholars mate animation.gif|frame|"[[Scholar's mate]]"]]
Moves are written as White/Black pairs, preceded by the move number and a period. Individual moves by White are also recorded this way, while moves by Black are written with an ellipsis after the move number. For example, one variation of a simple [[List of chess traps|trap]] known as the [[Scholar's mate]] (see animated diagram) can be recorded:
:1.e4 e5 2.Qh5{{chesspunc|?!}} Nc6 3.Bc4 Nf6{{chesspunc|??}} 4.Qxf7{{chessAN|#}}
The move 3...Nf6?? is recorded as a blunder, as it allows 4.Qxf7 checkmate.

Games or sequences may be recorded in [[Portable Game Notation]] (PGN), a text-based file format with support for annotative symbols, commentary, and background information, such as player names. It is based on short form English algebraic notation incorporating [[markup language]]. PGN transcripts, stored digitally as PGN (.pgn) files can be processed by most chess software and are easily readable by humans.

[[Algebraic notation (chess)#Naming the pieces|Variants of algebraic notation]] include ''long algebraic'', in which both the departure and destination square are indicated; ''abbreviated algebraic'', in which capture signs, check signs, and ranks of pawn captures may be omitted; and ''figurine algebraic notation'', used in chess books and magazines, which uses graphic symbols instead of initials to indicate pieces for readability regardless of language.

Until about 1980, the majority of English language chess publications used [[descriptive notation]], in which files are identified by the initial letter of the piece that occupies the first rank at the beginning of the game. In descriptive notation, the common opening move 1.e4 is rendered as "1.P-K4" ("pawn to king four"). Another system, [[ICCF numeric notation]], is recognized by the [[International Correspondence Chess Federation]].

In tournament games, players are normally required to keep a ''{{chessgloss|game score|score}}'' (written record of the game). This is a requirement in all FIDE-sanctioned games played at classical time controls.<ref name="FideLawsOfChess"/> For this purpose, only algebraic notation is recognized by FIDE, though variants such as long algebraic are acceptable; game scores recorded in a different notation system may not be used as evidence in the event of a dispute.

{{Clear}}

==Gameplay==

===Theory===
{{Main|Chess theory|Chess libraries|List of chess books|List of chess periodicals}}

Chess has an extensive literature. In 1913, the chess historian [[H.J.R. Murray]] estimated the total number of books, magazines, and [[chess columns in newspapers]] to be about 5,000.<ref>{{harvp|Murray|1985|p=25}}</ref> [[Baruch Harold Wood|B.H. Wood]] estimated the number, as of 1949, to be about 20,000.<ref name="harvp|Hooper|Whyld|1992|p=229">{{harvp|Hooper|Whyld|1992|p=229}}</ref> [[David Hooper (chess player)|David Hooper]] and [[Kenneth Whyld]] write that, "Since then there has been a steady increase year by year of the number of new chess publications. No one knows how many have been printed."<ref name="harvp|Hooper|Whyld|1992|p=229"/> Significant public chess libraries include the John G. White Chess and Checkers Collection at [[Cleveland Public Library]], with over 32,000 chess books and over 6,000 bound volumes of chess periodicals;<ref name="PolgarRecords">{{Cite web|date=2008-02-11|title= Special Chess Records|url=https://chessdailynews.com/special-chess-records/|access-date=2022-12-29|website=Chess Daily News |author= Susan Polgar| author-link= Susan Polgar |language=en-US|archive-date=29 December 2022|archive-url=https://web.archive.org/web/20221229064443/https://chessdailynews.com/special-chess-records/|url-status=live}}</ref> and the Chess & Draughts collection at the [[National Library of the Netherlands]], with about 30,000 books.<ref>{{cite web |url=http://www.kb.nl/en/resources-research-guides/kb-collections/collections-by-theme/chess-and-draughts-collection |title=Chess and draughts collection – Koninklijke Bibliotheek |work=kb.nl |url-status=live |archive-url=https://web.archive.org/web/20150602095256/http://www.kb.nl/en/resources-research-guides/kb-collections/collections-by-theme/chess-and-draughts-collection |archive-date=2 June 2015}}</ref>

===Strategy===
{{Main|Chess strategy}}

{| style="float:right;"
|- valign="top"
|+ Example of underlying pawn structure
|
{{col-begin|width=auto; float:right; clear:right}}
{{col-break}}
{{Chess diagram small
| tright
|
|rd|  |bd|  |rd|  |kd|
|pd|pd|  |nd|  |pd|bd|pd
|  |  |pd|rl|  |nd|pd|
|  |  |  |  |pd|  |  |
|  |  |pl|  |pl|  |  |
|  |  |nl|  |bl|nl|  |pl
|pl|pl|  |  |  |pl|pl|
|  |  |kl|  |  |bl|  |rl
|Position after 12...Re8 ...<br /><small>Tarrasch vs. Euwe, Bad Pistyan (1922)</small><ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1006866 |title=Siegbert Tarrasch vs. Max Euwe, Bad Pistyan it, CZE 1922 |website=[[Chessgames.com]] |url-status=live |archive-url=https://web.archive.org/web/20090110122502/http://www.chessgames.com/perl/chessgame?gid=1006866 |archive-date=10 January 2009}}</ref>
}}
{{col-break}}
{{Chess diagram small
| tright
|
|  |  |  |  |  |  |  |
|pd|pd|  |  |  |pd|  |pd
|  |  |pd|  |  |  |pd|
|  |  |  |  |pd|  |  |
|  |  |pl|  |pl|  |  |
|  |  |  |  |  |  |  |pl
|pl|pl|  |  |  |pl|pl|
|  |  |  |  |  |   | |
| ...&nbsp;and its pawn structure, known as the Rauzer formation
}}
{{col-end}}
|}

Chess strategy is concerned with the evaluation of chess positions and with setting up goals and long-term plans for future play. During the evaluation, players must take into account numerous factors such as the value of the pieces on the board, control of the center and centralization, the [[pawn structure]], king safety, and the control of [[key square]]s or groups of squares (for example, diagonals, open files, and dark or light squares).

The most basic step in evaluating a position is to count the [[Chess piece relative value|total value of pieces]] of both sides.<ref>{{harvp|Harding|2003|pp=1–7}}</ref> The point values used for this purpose are based on experience; usually, pawns are considered worth one point, knights and bishops about three points each, rooks about five points (the value difference between a rook and a bishop or knight being known as [[The exchange (chess)|the exchange]]), and queens about nine points. The king is more valuable than all of the other pieces combined, since its checkmate loses the game, but is still capable as a fighting piece; in the endgame, the king is generally more powerful than a bishop or knight but less powerful than a rook.<ref>{{harvp|Lasker|1934|p=73}}</ref> These basic values are then modified by other factors like position of the piece (e.g. advanced pawns are usually more valuable than those on their initial squares), coordination between pieces (e.g. a pair of bishops usually coordinate better than a bishop and a knight), or the type of position (e.g. knights are generally better in {{chessgloss|closed game|closed positions}} with many pawns while bishops are more powerful in {{chessgloss|open game|open positions}}).<ref>{{harvp|Watson|1998|pp=163ff}}</ref>

Another important factor in the evaluation of chess positions is ''[[pawn structure]]'' (sometimes known as the ''pawn skeleton''): the configuration of pawns on the chessboard.<ref>{{harvp|Harding|2003|pp=138ff}}</ref> Since pawns are the least mobile of the pieces, pawn structure is relatively static and largely determines the strategic nature of the position. Weaknesses in pawn structure include [[Isolated pawn|isolated]], [[Doubled pawns|doubled]], or [[backward pawn]]s and {{chessgloss|holes}}; once created, they are often permanent. Care must therefore be taken to avoid these weaknesses unless they are compensated by another valuable asset (for example, by the possibility of developing an attack).<ref>{{harvp|Evans|1958|pp=22–67}}</ref>
{{clear left}}

===Tactics===
{{Main|Chess tactic}}

In chess, tactics generally refer to short-term maneuvers—so short-term that they can be calculated in advance by a human player. The possible depth of calculation depends on the player's ability. In {{chessgloss|quiet move|quiet}} positions with many possibilities on both sides, a deep calculation is more difficult and may not be practical, while in positions with a limited number of {{chessgloss|forced move|forced}} variations, strong players can calculate long sequences of moves.

Theoreticians describe many elementary tactical methods and typical maneuvers, for example: [[Pin (chess)|pins]], [[Fork (chess)|forks]], [[Skewer (chess)|skewers]], [[Battery (chess)|batteries]], [[discovered attack]]s (especially discovered checks), [[zwischenzug]]s, [[Deflection (chess)|deflections]], [[Decoy (chess)|decoys]], [[Sacrifice (chess)|sacrifices]], [[Undermining (chess)|underminings]], [[Overloading (chess)|overloadings]], and [[Interference (chess)|interferences]].<ref>{{harvp|Harding|2003|pp=8ff}}</ref> Simple one-move or two-move tactical actions—threats, exchanges of {{chessgloss|material}}, and double attacks—can be combined into longer sequences of tactical maneuvers that are often forced from the point of view of one or both players. A forced variation that involves a sacrifice and usually results in a tangible gain is called a ''[[Combination (chess)|combination]]''.<ref>{{harvp|Harding|2003|pp=70ff}}</ref> Brilliant combinations, such as those in the [[Immortal Game]], are considered beautiful and are admired by chess lovers.

A [[Chess puzzle#Tactical puzzles|common type of chess exercise]], aimed at developing players' tactical skills, is a position where a combination is available and the challenge is to find it. Such positions are usually taken from actual games or from analysis of actual games. Solutions usually result in checkmate, decisive advantage, or successful defense. Tactical exercises are commonly found in instructional books, chess magazines, newspaper chess columns, and internet chess sites.<ref>{{harvp|Burgess|Nunn|Emms|2004|pp=14–15}}</ref>

===Phases===
Chess theory divides chess games into three phases with different sets of strategies: the [[#Opening|opening]], the [[#Middlegame|middlegame]], and lastly the [[#Endgame|endgame]]. There is no universally accepted way to delineate the three phases of the game; the middlegame is typically considered to have begun after 10–20 moves, and the endgame when only a few pieces remain.

====Opening====
{{Main|Chess opening}}

{{Chess diagram  
|tright
|
|rd|nd|bd|qd|kd|bd|  |rd
|  |pd|  |  |pd|pd|pd|pd
|pd|  |  |pd|  |nd|  |  
|  |  |  |  |  |  |  |  
|  |  |  |nl|pl|  |  |  
|  |  |nl|  |  |  |  |  
|pl|pl|pl|  |  |pl|pl|pl
|rl|  |bl|ql|kl|bl|  |rl
|The [[Sicilian Defense, Najdorf Variation|Najdorf Variation]] (5... a6), a popular line of the [[Sicilian Defense]] (1... c5), itself a response to the [[King's Pawn Game]] (1. e4)
}}
Competitive players typically learn, memorize, and play well-documented sequences of opening moves. The most common starting moves for White are 1.e4 and 1.d4, which usually lead to substantially different types of positions, and Black has multiple viable responses to both.

Sequences of opening moves are referred to as ''openings'' and are catalogued in reference works, such as the ''[[Encyclopaedia of Chess Openings]]''. There are thousands of openings, though only a small fraction of them are commonly played; variations of openings may also be given names. Openings vary widely in character from quiet {{chessgloss|positional play}} (for example, the [[Réti Opening]]) to {{chessgloss|sharp}} aggressive play (like the [[Latvian Gambit]]). In some opening lines, the exact sequence considered best for both sides has been worked out to more than 30 moves.<ref>{{harvp|Tamburro|2010|p=18}}</ref>

The fundamental strategic aims of most openings are similar:<ref>{{harvp|Tarrasch|1987}}</ref>
* ''Development:'' moving pieces (particularly bishops and knights) forward to squares on which they are useful (defending, attacking, and controlling important squares) or have the potential to take part in future plans and ideas.
* ''Control of the {{chessgloss|center}}:'' control of the central squares allows pieces to be moved to any part of the board relatively easily, and can inhibit the mobility of the opponent's pieces.
* ''King safety:'' typically secured by castling; incorrectly timed castling can be wasteful or even harmful, however.
* ''[[Pawn structure]]:'' players strive to avoid the creation of pawn weaknesses such as isolated, doubled, or backward pawns—and to force such weaknesses in the opponent's position.

Most players and [[Chess theory|theoreticians]] consider that White, by virtue of the [[Initiative (chess)|initiative]] granted from moving first, [[First-move advantage in chess|begins the game with a small advantage]].<ref>{{harvp|Evans|1958|p=175}}</ref> Black usually strives to neutralize White's advantage and achieve {{chessgloss|equality}}, or to develop {{chessgloss|dynamic}} {{chessgloss|counterplay}} in an unbalanced position.

====Middlegame====
{{Main|Chess middlegame}}

The middlegame is the part of the game that starts after the opening. Because the opening theory has ended, players have to form plans based on the features of the position, and at the same time take into account the tactical possibilities of the position.<ref>{{harvp|Harding|2003|pp=32–151}}</ref> The middlegame is the phase in which most [[Combination (chess)|combinations]] occur. Combinations are a series of tactical moves executed to achieve some gain. Middlegame combinations are often connected with an attack against the opponent's king. Some typical patterns have their own names; for example, the [[Boden's Mate]] or the [[Lasker - Bauer, Amsterdam, 1889|Lasker–Bauer]] combination.<ref>{{harvp|Hooper|Whyld|1992|p=86}}</ref>

Specific plans or strategic themes will often arise from particular groups of openings that result in a specific type of pawn structure. An example is the {{chessgloss|minority attack}}, which is the attack of queenside pawns against an opponent who has more pawns on the queenside. The study of openings is therefore connected to the preparation of plans that are typical of the resulting middlegames.<ref>{{harvp|Silman|1998|pp=202–205}}</ref>

Another important strategic question in the middlegame is whether and how to reduce material and transition into an endgame (i.e. {{chessgloss|simplify}}). Minor material advantages can generally be transformed into victory only in an endgame, and therefore the stronger side must choose an appropriate way to achieve an ending. Not every reduction of material is good for this purpose; for example, if one side keeps a light-squared bishop and the opponent has a dark-squared one, the transformation into a [[Chess endgame#Bishop and pawn endings|bishops and pawns]] ending is usually advantageous for the weaker side only, because an endgame with [[opposite-colored bishops endgame|bishops on opposite colors]] is likely to be a draw, even with an advantage of a pawn, or sometimes even with a two-pawn advantage.<ref>{{harvp|Emms|2004|p=90}}</ref>

====Endgame====
{{Main|Chess endgame}}

{{Chess diagram  
|tright
|Example of zugzwang
|  |  |kd|  |  |  |  | 
|  |  |pl|  |  |  |  | 
|  |  |  |kl|  |  |  | 
|  |  |  |  |  |  |  | 
|  |  |  |  |  |  |  | 
|  |  |  |  |  |  |  | 
|  |  |  |  |  |  |  | 
|  |  |  |  |  |  |  | 
|The side to move is disadvantaged.
}}

The endgame (also ''end game'' or ''ending'') is the stage of the game when there are few pieces left on the board. There are three main strategic differences between earlier stages of the game and the endgame:<ref>{{harvp|Harding|2003|pp=187ff}}</ref>
* Pawns become more important. Endgames often revolve around endeavors to [[Promotion (chess)|promote]] a pawn by advancing it to the furthest {{chessgloss|rank}}.
* The king, which requires safeguarding from attack during the middlegame, emerges as a strong piece in the endgame. It is often used to protect its own pawns, attack enemy pawns, and hinder moves of the opponent's king.
* [[Zugzwang]], a situation in which the player who is to move is forced to incur a disadvantage, is often a factor in endgames but rarely in other stages of the game. In the example diagram, either side having the move is in zugzwang: Black to move must play 1...Kb7 allowing White to promote the pawn after 2.Kd7; White to move must permit a draw, either by 1.Kc6 [[stalemate]] or by losing the pawn after any other legal move.

Endgames can be classified according to the type of pieces remaining on the board. [[Checkmate#Basic checkmates|Basic checkmates]] are positions in which one side has only a king and the other side has one or two pieces and can checkmate the opposing king, with the pieces working together with their king. For example, [[king and pawn endgame]]s involve only kings and pawns on one or both sides, and the task of the stronger side is to promote one of the pawns. Other more complicated endings are classified according to pieces on the board other than kings, such as "[[rook and pawn versus rook]]" endgames.
{{clear}}

==Problems and studies==
{{Chess diagram  
|tright
|[[Richard Réti]] <br />''[[Ostrava|Ostrauer]] Morgenzeitung'', 1921
|  |  |  |  |  |  |  |kl
|  |  |  |  |  |  |  |
|kd|  |pl|  |  |  |  |
|  |  |  |  |  |  |  |pd
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|{{center|White to move and draw}} {{pb}}[[Réti endgame study|This endgame study]] is solved by advancing the white king [[diagonal]]ly, simultaneously stopping the black pawn and supporting the white pawn on its way to {{chessgloss|queening|queen}}.<ref>{{harvp|de la Villa|2008|pp=179–180}}</ref>
}}

[[Chess problems]] (also called chess compositions) are composed positions, usually created for artistic effect rather than practical application. The creator is known as a [[chess composer]].<ref>{{harvp|Howard|1961}}</ref> There are many types of chess problems, the most common being {{chessprobgloss|directmates}}, in which White is required to move and checkmate Black within a specified number of moves, usually two or three, against any defense.

These are commonly referred to as "two-movers", "three-movers", or "more-movers". "Many-movers" (also known as "long-range problems") of over 100 moves have been composed, the current record standing at over 200; these usually require repetitions of the same manoeuvre in order to produce a repeated [[zugzwang]] and force detrimental pawn advances.<ref>{{harvp|Hooper|Whyld|1992|p=234}}</ref><ref>{{cite web |author=John Nunn|authorlink=John Nunn|date=12 May 2015 |title=Longest dual-free direct mate problem |url=https://en.chessbase.com/post/longest-dual-free-direct-mate-problem |website=Chessbase.com |access-date=30 January 2025}}</ref>

Directmates usually consist of positions unlikely to occur in an actual game, and are intended to illustrate a particular ''{{chessprobgloss|theme}}'', usually requiring a surprising or counterintuitive ''{{chessprobgloss|key}}'' move. Themes associated with chess problems occasionally appear in actual games, when they are referred to as "problem-like" moves.<ref>{{harvp|Hooper|Whyld|1992|p=110}}</ref>

Other common types of problems include:
*[[Helpmate]]s, in which Black moves first and cooperates with White to get Black's king checkmated
*[[Selfmate]]s, in which White moves first and forces Black to checkmate White
*[[Retrograde analysis problems]], in which the solver is required to work out what has previously occurred in the game, for example to prove that castling is illegal in the current position

The above type of problems are usually considered orthodox, in the sense that the standard rules of chess are observed.

[[Fairy chess]] problems, also called heterodox problems, involve altered rules, such as the use of unconventional pieces or boards, or stipulations that contradict the standard rules of chess such as [[reflexmate]]s or [[seriesmover]]s.

[[Endgame study|Studies]] are usually considered distinct from problems, although there is some overlap. In a study, the stipulation is that White to play must win or draw, without specifying any particular number of moves. The majority of studies are [[Chess endgame|endgame]] positions, with varying degrees of realism or practical application.<ref>{{harvp|Hooper|Whyld|1992|pp=400–401}}</ref>

Tournaments for composition and solving of chess problems and studies are organized by the [[World Federation for Chess Composition]] (WFCC), which works cooperatively with but independent of FIDE. The WFCC awards titles for composing and solving chess problems.<ref>{{harvp|Weenink|1926}}</ref>

==Chess in public spaces==
Chess is often played in public spaces such as parks and town squares. Although the nature of these games is often {{chessgloss|friendly game|casual}}, the chess [[hustling]] scene has seen growth in urban areas such as [[New York City]].<ref>{{Cite web |last=Hercules |first=Andrew |date=11 January 2021 |url=https://herculeschess.com/what-is-chess-hustling/ |title=What Is Chess Hustling & How Much Do Chess Hustlers Make? |website=Hercules Chess |access-date=28 January 2025 |archive-date=19 February 2025 |archive-url=https://web.archive.org/web/20250219211635/https://herculeschess.com/what-is-chess-hustling/ |url-status=dead }}</ref><!-- Do we really need this many pictures? -->

{{Gallery|mode=packed|align=left|height=150|width=150
|File:Player in Washington Square park.jpg|A child playing chess in [[Washington Square Park]], New York City, US 
|File:Paris - Playing chess at the Jardins du Luxembourg - 2955.jpg|Public chess tables in the [[Jardin du Luxembourg]], Paris, France
|File:2014 Kutaisi, Mężczyzni grający w szachy (01).jpg|Men playing chess, [[Kutaisi]], Georgia, 2014
|File:Concentrancia (156917957).jpg|A girl playing chess in [[Mexico City]], Mexico
|File:Chess game in Kilifi Kenya.jpg|Chess game in [[Kilifi]], Kenya 
|File:Chch 05.JPG|Giant chess in [[Cathedral Square, Christchurch|Cathedral Square]], [[Christchurch]], New Zealand, 2005
|File:Children Playing Chess on the Street - Santiago de Cuba - Cuba.jpg|Boys playing chess on a street in [[Santiago de Cuba]], Cuba
|File:Széchenyi Gyógyfürdő, 2011. Chess in the Budapest Baths (6050758790).jpg|Chess players in the [[Széchenyi thermal bath|Széchenyi baths]] of [[Budapest]], Hungary
|File:Salatiga - Playing chess at the Tegalrejo, Argomulyo, Salatiga.jpg|A girl playing chess in [[Salatiga]], Indonesia
|File:Schack - Lund 2007.jpg|Two men play chess at the Ariman cafe in [[Lund]] in 2007.
}}
{{clear}}

==Organized competition==

===Tournaments and matches===
[[File:TataSteelChess2019-11.jpg|thumb|right|[[Tata Steel Chess Tournament]] 2019, Wijk aan Zee (the Netherlands)]]
Contemporary chess is an organized sport with structured international and national leagues, tournaments, and [[congress]]es. Thousands of chess tournaments, matches, and festivals are held around the world every year catering to players of all levels.

Tournaments with a small number of players may use the [[Round-robin tournament|round-robin]] format, in which every player plays one game against every other player. For a large number of players, the [[Swiss-system tournament|Swiss system]] may be used, in which each player is paired against an opponent who has the same (or as similar as possible) score in each round. In either case, a player's score is usually calculated as 1 point for each game won and one-half point for each game drawn. Variations such as "football scoring" (3 points for a win, 1 point for a draw) may be used by tournament organizers, but ratings are always calculated on the basis of standard scoring. A player's score [[Chess scoring|may be reported]] as total score out of games played (e.g. 5½/8), points for versus points against (e.g. 5½–2½), or by number of wins, losses and draws (e.g. +4−1=3).

The term "match" refers not to an individual game, but to either a series of games between two players, or a team competition in which each player of one team plays one game against a player of the other team.

===Governance===
Chess's international governing body is usually known by its French acronym [[FIDE]] (pronounced FEE-day; [[French language|French]]: ''Fédération Internationale des Échecs''), or International Chess Federation. FIDE's membership consists of the national chess organizations of over 180 countries; there are also several associate members, including various supra-national organizations, the [[International Braille Chess Association]] (IBCA), [https://chessdeaf.org/ International Chess Committee of the Deaf ] (ICCD), and the [https://ipcachess.org/  International Physically Disabled Chess Association ] (IPCA).<ref>{{Cite web |url=https://www.fide.com/directory/affiliated-organizations |title=FIDE - Affiliated organizations |access-date=26 February 2021 |archive-date=24 February 2021 |archive-url=https://web.archive.org/web/20210224160953/https://www.fide.com/directory/affiliated-organizations |url-status=live }}</ref> FIDE is recognized as a [[sports governing body]] by the [[International Olympic Committee]],<ref>{{cite web |url=https://www.arisf.sport/members.aspx |title=Association of IOC Recognised International Sports Federations |publisher=International Olympic Committee |access-date=14 January 2021 |archive-date=22 January 2021 |archive-url=https://web.archive.org/web/20210122114531/https://www.arisf.sport/members.aspx |url-status=live }}</ref> but chess has never been part of the [[Olympic Games]].

[[File:Kasparov-29.jpg|thumb|upright|[[Garry Kasparov]], former World Chess Champion]]
FIDE's most visible activity is organizing the [[World Chess Championship]], a role it assumed in 1948. The current World Champion is [[Gukesh Dommaraju]] of India.<ref>{{Cite web |title=Gukesh defeats Ding, takes 6-5 lead in world chess championship |url=https://www.aljazeera.com/sports/2024/12/8/gukesh-defeats-ding-takes-6-5-lead-in-world-chess-championship |access-date=2024-12-13 |website=Al Jazeera |language=en}}</ref><ref name="WCC2023">{{Cite web |title=Ding Liren defeats Ian Nepomniachtchi to win World Chess Championship – live |url=https://www.msn.com/en-gb/sport/tennis/ding-liren-defeats-ian-nepomniachtchi-to-win-world-chess-championship-live/ar-AA1ay88z |access-date=2023-04-30 |website=MSN |language=en-GB |archive-date=30 April 2023 |archive-url=https://web.archive.org/web/20230430135051/https://www.msn.com/en-gb/sport/tennis/ding-liren-defeats-ian-nepomniachtchi-to-win-world-chess-championship-live/ar-AA1ay88z |url-status=live }}</ref> The reigning [[Women's World Chess Championship|Women's World Champion]] is [[Ju Wenjun]] from China.<ref>{{cite web |url=https://en.chessbase.com/post/womens-world-championship-2020-ju-goryachkina-game-12 |title=Women's World Championship 2020 - Ju wins tiebreak |website=chessbase.com |date=24 January 2020 |access-date=26 February 2020 |archive-date=24 January 2020 |archive-url=https://web.archive.org/web/20200124185454/https://en.chessbase.com/post/womens-world-championship-2020-ju-goryachkina-game-12 |url-status=live }}</ref>

Other competitions for individuals include the [[World Junior Chess Championship]], the [[European Individual Chess Championship]], the [[Candidates Tournament|tournaments for the World Championship qualification cycle]], and the various [[List of national chess championships|national championships]]. Invitation-only tournaments regularly attract the world's strongest players. Examples include Spain's [[Linares chess tournament|Linares]] event, Monte Carlo's [[Melody Amber]] tournament, the [[Dortmund Sparkassen Chess Meeting|Dortmund Sparkassen]] meeting, Sofia's [[M-tel Masters]], and [[Wijk aan Zee]]'s [[Tata Steel Chess Tournament|Tata Steel]] tournament.

Regular team chess events include the [[Chess Olympiad]] and the [[European Team Chess Championship]].

The [[World Chess Solving Championship]] and [[World Correspondence Chess Championship]] include both team and individual events. These are held independently of FIDE by, respectively, the [[World Federation for Chess Composition]] (WFCC) and the [[International Correspondence Chess Federation]] (ICCF).

===Titles and rankings===
{{Main|Chess titles}}

In order to rank players, FIDE, [[International Correspondence Chess Federation|ICCF]], and most national chess organizations use the [[Elo rating system]] developed by [[Arpad Elo]]. An average club player has a rating of about 1500; the highest FIDE rating of all time, 2882, was achieved by [[Magnus Carlsen]] on the March 2014 FIDE rating list.<ref>{{cite news |title=Carlsen with record-breaking lead |url=http://chessbase.com/newsdetail.asp?newsid=8744 |publisher=ChessBase News |date=1 January 2013 |access-date=16 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130122115753/http://chessbase.com/newsdetail.asp?newsid=8744 |archive-date=22 January 2013}}</ref>

Players may be awarded lifetime titles by FIDE:{{refn|Section "01. International Title Regulations (Qualification Commission)" in FIDE Handbook<ref name="FideHandbook">{{cite web|title=FIDE Handbook|url=https://handbook.fide.com/|access-date=5 July 2020|website=FIDE|archive-date=8 January 2021|archive-url=https://web.archive.org/web/20210108150228/https://handbook.fide.com/|url-status=live}}</ref>}}
* [[Grandmaster (chess)|Grandmaster]] (GM) is the highest title a chess player can attain. For the GM title, a player must have had an Elo rating of 2500 or more at least once and must achieve three results of a prescribed standard (called norms) in tournaments involving other grandmasters, including some from countries other than the applicant's. There are other milestones that can substitute for norms, such as winning the World Junior Championship.
* [[International Master]] (IM). The conditions are similar to GM, but less demanding. The minimum rating for the IM title is 2400.
* [[FIDE Master]] (FM). The usual way for a player to qualify for the FIDE Master title is by achieving a FIDE rating of 2300 or more.
* [[Candidate Master]] (CM). Similar to FM, but with a FIDE rating of at least 2200.

The above titles are known as "open" titles, obtainable by both men and women. There are also separate women-only titles: Woman Grandmaster (WGM), Woman International Master (WIM), Woman FIDE Master (WFM) and Woman Candidate Master (WCM). These require a performance level approximately 200 rating points below their respective open titles, and their continued existence has sometimes been controversial.{{citation needed|date=January 2025}} Beginning with [[Nona Gaprindashvili]] in 1978, a number of women have earned the open GM title: 40 {{as of|lc=yes|July 2023}}.<ref group=note name="FIDE_top_players">Current FIDE lists of top players with their titles are online at {{Cite web|title=FIDE Ratings and Statistics|url=https://ratings.fide.com/|access-date=2022-12-29|website=ratings.fide.com|archive-date=10 July 2023|archive-url=https://web.archive.org/web/20230710101639/http://ratings.fide.com/|url-status=live}}</ref>

FIDE also awards titles for arbiters and trainers.{{refn|Section "06. Regulations for the Titles of Arbiters" in FIDE Handbook<ref name="FideHandbook" />}}{{refn|Section "07. Regulations for the Titles of Trainers" in FIDE Handbook<ref name="FideHandbook" />}} International titles are also awarded to composers and solvers of chess problems and to correspondence chess players (by the [[International Correspondence Chess Federation]]). National chess organizations may also award titles.

==History==
{{Main|History of chess}}

===Origins===
[[File:King Khosrow sits before the chessboard, while his vizir and the envoy of Qannuj are playing chess. Shahnameh, 10th century CE.jpg|thumb|upright=1.4|[[Sasanian Empire]] King [[Khosrow I]] sits on his throne before the chessboard, while his vizir and the Indian envoy Deva Sharma, probably sent by the [[Maukhari]] King [[Śarvavarman]] of [[Kannauj]], are playing chess. ''[[Shahnama]]'', 10th century AD.<ref name="ME">{{cite book |last1=Eder |first1=Manfred A. J. |title=South Asian Archaeology 2007 Proceedings of the 19th Meeting of the European Association of South Asian Archaeology in Ravenna, Italy, July 2007, Volume II |date=2010 |publisher=Archaeopress Archaeology |isbn=978-1-4073-0674-2 |page=69 |url=http://history.chess.free.fr/papers/Eder%202007-2.pdf |access-date=21 November 2021 |archive-date=20 November 2021 |archive-url=https://web.archive.org/web/20211120194215/http://history.chess.free.fr/papers/Eder%202007-2.pdf |url-status=live }}</ref><ref>{{cite book |last1=Bakker |first1=Hans T. |author-link=Hans T. Bakker |title=The Huns in Central and South Asia. How Two Centuries of War against Nomadic Invaders from the Steps are Concluded by a Game of Chess between the Kings of India and Iran |date=2017 |url=https://www.academia.edu/34156496 |access-date=21 November 2021 |archive-date=20 March 2022 |archive-url=https://web.archive.org/web/20220320115332/https://www.academia.edu/34156496 |url-status=live }}</ref>]]
Texts referring to the origins of chess date from the beginning of the seventh century. Three are written in ''Pahlavi'' ([[Middle Persian]])<ref>{{Cite book|title=La novella degli scacchi e della tavola reale|last=Panaino|first=Antonio|publisher=Mimesis|year=1999|isbn=88-87231-26-5|location=Milano}}</ref> and one, the ''[[Harshacharita]]'', is in [[Sanskrit]].<ref>Andreas Bock-Raming, The Gaming Board in Indian Chess and Related Board Games: a terminological investigation, Board Games Studies 2, 1999</ref> One of these texts, the ''Chatrang-namak'', represents one of the earliest written accounts of chess. The narrator [[Bozorgmehr]] explains that ''Chatrang'', "Chess" in Pahlavi, was introduced to Persia by '[[Sharvavarman|Dewasarm]], a great ruler of India' during the reign of [[Khosrow I]]:<ref>{{harvp|Warner|2000|p=381}}</ref>

{{blockquote|Dewasarm has fashioned this ''[[chatrang]]'' after the likeness of a battle, and in its likeness are two supreme rulers after the likeness of Kings (shah), with the essentials of rooks (rukh) to right and to left, with Counsellor (farzin) in the likeness of a commander of the champions, with the Elephant (pil) in the likeness of the commander of the rearguard, with Horse (asp) in the likeness of the commander of the cavalry, with the Footsoldier (piyadak) in the likeness of so many infantry in the vanguard of the battle.|Translation by Murray, 1913.{{sfn|Mark|2007|p=148}}}}

[[File:A treatise on chess 2.jpg|thumb|An illustration from a Persian manuscript "A treatise on chess". The Ambassadors from India present the Chatrang to Khosrow I Anushirwan, "Immortal Soul", King of Persia, 14th century AD.|left]]
The oldest known chess manual was in Arabic and dates to about 840, written by [[al-Adli ar-Rumi]] (800–870), a renowned Arab chess player, titled ''Kitab ash-shatranj'' (The Book of Chess). This is a lost manuscript, but is referenced in later works.<ref>{{harvp|Murray|1985|pp=169–174}}</ref> Here also, al-Adli attributes the origins of Persian chess to India, along with the eighth-century collection of fables [[Kalīla wa-Dimna]].<ref name="Elephants and Kings">{{harvp|Trautmann|2015|p=117}}</ref> By the 20th century, a substantial consensus{{sfn|Mark|2007|p=138}}<ref>{{harvp|Fine|2015|p=3}}</ref> developed regarding chess's origins in northwest [[India]] in the early seventh century.<ref>{{harvp|Murray|1985|pp=26–27, 51–52}}</ref> More recently, this consensus has been the subject of further scrutiny.<ref>{{cite web|date=2012-08-08|title=A critical review of: "The Beginnings of Chess"|url=http://history.chess.free.fr/mark2007.htm|publisher=Jean-Louis Cazaux|access-date=4 May 2021|archive-date=8 August 2021|archive-url=https://web.archive.org/web/20210808032318/http://history.chess.free.fr/mark2007.htm|url-status=live}}</ref>

The early forms of chess in India were known as ''[[chaturanga|chaturaṅga]]'' ({{Langx|sa|चतुरङ्ग}}), literally "four divisions" [of the military]&nbsp;– [[infantry]], [[cavalry]], [[war elephant|elephants]], and [[chariot]]ry – represented by pieces that would later evolve into the modern pawn, knight, bishop, and rook, respectively. Chaturanga was played on an 8×8 uncheckered board, called ''[[Ashtapada|ashtāpada]]''.<ref>{{cite web|date=2005-07-25|title=Ashtapada|url=http://history.chess.free.fr/ashtapada.htm|access-date=2013-07-16|publisher=Jean-Louis Cazaux|archive-date=25 July 2017|archive-url=https://web.archive.org/web/20170725185540/http://history.chess.free.fr/ashtapada.htm|url-status=live}}</ref> Thence it spread eastward and westward along the [[Silk Road]]. The earliest evidence of chess is found in nearby [[Sasanian Persia]] around 600 A.D., where the game came to be known by the name ''[[chatrang]]'' ({{langx|fa|چترنگ}}).<ref>{{Cite journal |last=Eiland |first=Murray |date=2013 |title=Some Problems of Islamic Heraldry |url=https://www.academia.edu/8013404 |journal=The Armiger's News |volume=35 |issue=2 |pages=1–5 |via=academia.edu |access-date=27 December 2022 |archive-date=3 February 2023 |archive-url=https://web.archive.org/web/20230203011606/https://www.academia.edu/8013404 |url-status=live }}</ref> Chatrang was taken up by the [[Muslim world]] after the [[Islamic conquest of Persia]] (633–51), where it was then named ''[[shatranj]]'' ({{langx|ar|شطرنج}}; {{langx|fa|شترنج}}), with the pieces largely retaining their Persian names. In Spanish, "shatranj" was rendered as ''ajedrez'' ("al-shatranj"), in [[Portuguese language|Portuguese]] as ''xadrez'', and in [[Greek language|Greek]] as ζατρίκιον (''zatrikion'', which comes directly from the Persian ''chatrang''),<ref>{{harvp|Murray|1985|p=163}}</ref> but in the rest of Europe it was replaced by versions of the Persian ''shāh'' ("king"), from which the English words "check" and "chess" descend.{{refn|At that time the Spanish word would have been written ''axedrez''. The Spanish "x" was pronounced as English "sh", as the Portuguese "x" still is today. The spelling of ''ajedrez'' changed after [[Spanish orthography#History|Spanish lost the "sh" sound]].|group=note}} The word "[[checkmate]]" is derived from the Persian ''shāh māt'' ("the king is dead").<ref>{{cite web |url=http://www.etymonline.com/index.php?term=checkmate |title=Online Etymology Dictionary |access-date=2 May 2020 |last=Harper |first=Douglas |author2=Dan McCormack |archive-date=2 November 2012 |archive-url=https://web.archive.org/web/20121102052251/http://www.etymonline.com/index.php?term=checkmate |url-status=live }}</ref>

[[File:KnightsTemplarPlayingChess1283.jpg|thumb|upright=1.3|[[Knights Templar]] playing chess, {{lang|es|[[Libro de los juegos]]}}, 1283]]

[[Xiangqi]] is the form of chess best known in China. The eastern migration of chess, into China and Southeast Asia, has even less documentation than its migration west, making it largely conjectured. The word ''xiàngqí'' ({{lang|zh|象棋}}) was used in China to refer to a game from 569 A.D. at the latest, but it has not been proven that this game was directly related to chess.<ref>Peter Banaschak, Facts on the origin of Chinese chess (Xiangqi), 4th Symposium of the Initiative Gruppe Königstein, Wiesbaden, August 1997</ref><ref>{{Cite book|title=Understanding the Elephant, Part 1: History of Xiangqi|last=Png Hau Cheng|first=Jim|year=2016|isbn=978-957-43-3998-3|publisher=Jim Png Hau Cheng|location=New Taipei City}}</ref>
The first reference to Chinese chess appears in a book entitled ''Xuánguaì Lù'' ({{lang|zh|玄怪錄}}; "Record of the Mysterious and Strange"), dating to about 800. A minority view holds that Western chess arose from xiàngqí or one of its predecessors.<ref>{{harvp|Li|1998}}</ref><ref>{{cite web |last=Banaschak |first=Peter |title=A story well told is not necessarily true: a critical assessment of David H. Li's ''The Genealogy of Chess'' |url=http://www.banaschak.net/schach/ligenealogyofchess.htm |url-status=live |archive-url=https://web.archive.org/web/20130511071131/http://www.banaschak.net/schach/ligenealogyofchess.htm |archive-date=11 May 2013}}</ref> Chess historians Jean-Louis Cazaux and Rick Knowlton contend that xiangqi's intrinsic characteristics make it easier to construct an evolutionary path from China to India/Persia than the opposite direction.<ref>{{Cite book|title=A World of Chess, Its Development and Variations through Centuries and Civilisations|last1=Cazaux|first1=Jean-Louis|publisher=McFarland|year=2017|isbn=9-780786-494279|pages=334–353 (The origins of chess, approaching the question from several angles)|last2=Knowlton|first2=Rick}}</ref>

The oldest archaeological chess artifacts – ivory pieces – were excavated in ancient [[Afrasiyab (Samarkand)|Afrasiab]], today's [[Samarkand]], in [[Uzbekistan]], Central Asia, and date to about 760, with some of them possibly being older. Remarkably, almost all findings of the oldest pieces come from along the Silk Road, from the former regions of the Tarim Basin (today's Xinjiang in China), [[Transoxiana]], [[Sogdiana]], [[Bactria]], [[Gandhara]], to Iran on one end and to India through [[Kashmir]] on the other.<ref>{{Cite book|title=Chess and other games pieces from Islamic Lands|last=Freeman Fahid|first=Deborah|publisher=Thames & Hudson|year=2018|isbn=978-0-500-97092-8|location=London}}</ref>

[[File:Chess pieces from Samarkand 700s.jpg|thumb|These are some of the seven Early Islamic ivory chess pieces excavated in [[Afrasiyab (Samarkand)|Samarkand]] in 1977. They date to the 700s and are among the oldest in the world.<ref>{{harvp|Brunning|Yu-Ping|O'Connell|Williams|2024|pp=151–152}}</ref>  The ivory came from India.]]

The game reached Western Europe and Russia via at least three routes, the earliest being in the ninth century. By the year 1000, it had spread throughout both the [[Al Andalus|Muslim Iberia]] and [[Latin Christianity|Latin Europe]].<ref>{{harvp|Hooper|Whyld|1992||pp=173–175}}</ref> A Latin poem called ''[[Versus de scachis]]'' ("Verses on Chess") dated to the late 10th century, has been preserved at [[Einsiedeln Abbey]] in Switzerland.

===1200–1700: Origins of the modern game===
The game of chess was then played and known in all European countries. A famous 13th-century Spanish manuscript covering chess, [[backgammon]], and [[dice]] is known as the {{lang|es|[[Libro de los juegos]]}}, which is the earliest [[Europe]]an treatise on chess as well as being the oldest document on European [[tables games]].<ref>{{cite journal |last1=Ilko |first1=Krisztina |title=Chess and Race in the Global Middle Ages |journal=Speculum |date=2024 |volume=99 |issue=2 |pages=505–519 |doi=10.1086/729294|issn = 0038-7134}}</ref> The rules were fundamentally similar to those of the Arabic [[shatranj]]. The differences were mostly in the use of a checkered board instead of a plain monochrome board used by Arabs and the habit of allowing some or all pawns to make an initial double step. In some regions, the queen, which had replaced the [[Wazir (chess)|wazir]], or the king could also make an initial two-square leap under some conditions.<ref>{{harvp|Murray|1985|pp=457–459}}</ref> 
[[File:Lucena110.png|thumb|right|A tactical puzzle from [[Luis Ramírez de Lucena|Lucena's]] 1497 book]]

Around 1200, the rules of shatranj started to be modified in Europe, culminating, several major changes later, in the emergence of modern chess practically as it is known today.<ref>{{harvp|Murray|1985|p=777}}</ref> A major change was the modern piece movement rules, which began to appear in intellectual circles in [[Valencia]], Spain, around 1475,{{refn|The allegorical poem [[Scachs d'amor]], the first to describe a modern game, is probably from 1475.<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1259987 |title=Francesco di Castellvi vs. Narciso Vinyoles (1475) "Old in Chess" |website=[[Chessgames.com]] |access-date=13 November 2021 |archive-date=28 January 2021 |archive-url=https://web.archive.org/web/20210128214712/https://www.chessgames.com/perl/chessgame?gid=1259987|url-status=live }}</ref><ref>{{Cite web|last=Negri|first=Sergio Ernesto|date=2020-03-16|title=Scachs d'amor: The poem that first portrayed the modern rules of chess|url=https://en.chessbase.com/post/scachs-damor-poem-part-1|url-status=live|access-date=2021-11-09|website=ChessBase|language=en|archive-url=https://web.archive.org/web/20200329222835/https://en.chessbase.com/post/scachs-damor-poem-part-1 |archive-date=29 March 2020 }}</ref>|group=note}} which established the foundations and brought it very close to current chess. These new rules then were quickly adopted in Italy and Southern France before diffusing into the rest of Europe.<ref>{{harvp|Davidson|1949|pp=13–17}}</ref><ref name="nauiua">{{cite web |author=Calvo, Ricardo |url=http://history.chess.free.fr/papers/Calvo%201998.pdf |title=Valencia Spain: The Cradle of European Chess |date=1998 |access-date=3 March 2015 |url-status=live |archive-url=https://web.archive.org/web/20160130113355/http://history.chess.free.fr/papers/Calvo%201998.pdf |archive-date=30 January 2016 |df=dmy-all}}</ref> Pawns gained the ability to advance two squares on their first move, while bishops and queens acquired their modern movement powers. The [[Queen (chess)|queen]] replaced the earlier [[Vizier#Influence on chess|vizier]] chess piece toward the end of the 10th&nbsp;century and by the 15th&nbsp;century had become the most powerful piece;<ref>{{harvp|Yalom|2004}}</ref> in light of that, modern chess was often referred to at the time as "Queen's Chess" or "Mad Queen Chess".<ref>{{harvp|Weissberger|2004|pp=152ff}}</ref> Castling, derived from the "king's leap", usually in combination with a pawn or rook move to bring the king to safety, was introduced. These new rules quickly spread throughout Western Europe.

Writings about [[chess theory]] began to appear in the late 15th&nbsp;century. An [[Göttingen manuscript|anonymous treatise on chess of 1490]] with the first part containing some openings and the second 30 endgames is deposited in the library of the [[University of Göttingen]].<ref name="Alex-1989">{{Cite book |last=Alex |first=Crisovan |url=https://books.google.com/books?id=nww4MQAACAAJ |title=1889-1989 : 100 Jahre Schweizerischer Schachverband: 100 ans de fdration suisse des checs |date=1989 |publisher=Verlag Zrcher |pages=54 |language=it |access-date=25 January 2023 |archive-date=3 February 2023 |archive-url=https://web.archive.org/web/20230203011446/https://books.google.com/books?id=nww4MQAACAAJ |url-status=live }}</ref> The book ''El Libro dels jochs partitis dels schachs en nombre de 100'' was written by [[Francesc Vicent]] in [[Segorbe]] in 1495, but no copy of this work has survived.<ref name="Alex-1989" /> The ''Repetición de Amores y Arte de Ajedrez'' (''Repetition of Love and the Art of Playing Chess'') by [[Spanish people|Spanish]] churchman [[Luis Ramírez de Lucena]] was published in [[Salamanca]] in 1497.<ref name="nauiua"/> Lucena and later masters like Portuguese [[Pedro Damiano]], Italians [[Giovanni Leonardo Di Bona]], [[Giulio Cesare Polerio]] and [[Gioachino Greco]], and Spanish bishop [[Ruy López de Segura]] developed elements of [[#Opening|opening theory]] and started to analyze simple [[#Endgame|endgames]].

===1700–1873: Romantic era===
[[File:immortal Game, 1851.gif|thumb|right|240px|The "[[Immortal Game]]", Anderssen vs. Kieseritzky, 1851]]
In the 18th century, the center of European chess life moved from Southern Europe to mainland France.<ref>{{Cite web |title=FIDE - World Chess Federation |url=https://old.fide.com/fide/fide-world-chess-federation.html |access-date=2025-10-05 |website=old.fide.com |at=Game of Chess and its History}}</ref> The two most important French masters were [[François-André Danican Philidor]], a musician by profession, who discovered the importance of pawns for chess strategy, and later [[Louis-Charles Mahé de La Bourdonnais]], who won a famous series of matches against Irish master [[Alexander McDonnell (chess player)|Alexander McDonnell]] in 1834.<ref>{{cite web |url=http://www.chessgames.com/perl/chessplayer?pid=31596 |title=Louis Charles Mahe De La Bourdonnais |website=[[Chessgames.com]] |access-date=26 November 2008 |url-status=live |archive-url=https://web.archive.org/web/20081229231938/http://www.chessgames.com/perl/chessplayer?pid=31596 |archive-date=29 December 2008 |df=dmy-all}}</ref> Centers of chess activity in this period were [[coffee house]]s in major European cities like ''[[Café de la Régence]]'' in Paris and ''[[Simpson's-in-the-Strand|Simpson's Divan]]'' in London.<ref>{{harvp|Metzner|1998}}</ref><ref>{{Cite book |last1=Bird|first1=Henry Edward |url=http://www.gutenberg.org/ebooks/4902 |title=Chess History and Reminiscences |access-date=26 November 2008 |publisher=Gutenberg |date=January 2004 |archive-url=https://web.archive.org/web/20090924125500/http://www.gutenberg.org/etext/4902 |edition=10|archive-date=24 September 2009 |url-status=live |author-link=Henry Edward Bird}}</ref>

At the same time, the [[Romanticism|Romantic]] intellectual movement had had a far-reaching impact on chess, with aesthetics and tactical beauty being held in higher regard than objective soundness and strategic planning. As a result, virtually all games began with the [[Open Game]], and it was considered unsportsmanlike to decline gambits that invited tactical play such as the [[King's Gambit]] and the [[Evans Gambit]].<ref name="Shenk, 2007">{{cite book|author=David Shenk|url=https://archive.org/details/isbn_9780385510103|title=The Immortal Game: A History of Chess|publisher=Knopf Doubleday|year=2007|page=[https://archive.org/details/isbn_9780385510103/page/99 99]|isbn=9780385510103|url-access=registration}}</ref> This chess philosophy is known as [[Romantic chess]], and its sharp, tactical style of play was predominant until the late 19th century.<ref>{{harvp|Landsberger|1992}}</ref>

[[Stalemate#History of the stalemate rule|The rules concerning stalemate]] were finalized in the early 19th&nbsp;century. Also in the 19th&nbsp;century, the convention that White moves first was established (formerly either White or Black could move first). Finally, the rules around castling and en passant captures were standardized—variations in these rules persisted in Italy until the late 19th&nbsp;century. The resulting standard game is sometimes referred to as ''Western chess''<ref>{{cite web |url=http://www.chessbase.com/newsdetail.asp?newsid=3492 |title=XiangQi – an alternate to Western Chess |publisher=ChessBase.com |author=René Gralla |url-status=live |archive-url=https://web.archive.org/web/20110604145052/http://www.chessbase.com/newsdetail.asp?newsid=3492 |archive-date=4 June 2011 |df=dmy-all |date=19 November 2006}}</ref> or ''international chess'',<ref>{{cite web |url=http://www.chessvariants.org/oriental.dir/thaikramnik.html |date=January 2, 2005|title=Kramnik plays Makruk Thai |first1=René|last1=Gralla |access-date=12 December 2010 |website=[[The Chess Variant Pages]] |url-status=live |archive-url=https://web.archive.org/web/20110606155706/http://www.chessvariants.org/oriental.dir/thaikramnik.html |archive-date=6 June 2011 |df=dmy-all}}</ref> particularly in Asia where other games of the chess family such as [[xiangqi]] are prevalent. Since the 19th&nbsp;century, the only rule changes, such as the establishment of the correct procedure for claiming a draw by repetition, have been technical in nature.

[[File:Jean Henri Marlet Das berühmte Schachspiel zwischen Howard Staunton und Pierre Charles Fourrier Saint-Amant 1843.jpg|thumbnail|right|A depiction of the chess match between [[Howard Staunton]] and [[Pierre Charles Fournier de Saint-Amant|Pierre Saint-Amant]], on 16 December 1843]]
As the 19th century progressed, chess organization developed quickly. Many [[chess club]]s, chess books, and chess journals appeared. There were correspondence matches between cities; for example, the London Chess Club played against the [[Edinburgh]] Chess Club in 1824.<ref>{{cite web |url=http://www.chessgames.com/perl/chessplayer?pid=80740 |title=London Chess Club |website=[[Chessgames.com]] |access-date=26 November 2008 |url-status=live |archive-url=https://web.archive.org/web/20081225144954/http://www.chessgames.com/perl/chessplayer?pid=80740 |archive-date=25 December 2008 |df=dmy-all}}</ref> [[Chess problems]] became a regular part of 19th-century newspapers; [[Bernhard Horwitz]], [[Josef Kling]], and [[Samuel Loyd]] composed some of the most influential problems. In 1843, [[Tassilo von Heydebrand und der Lasa|von der Lasa]] published his and [[Paul Rudolf von Bilguer|Bilguer's]] ''[[Handbuch des Schachspiels]]'' (''Handbook of Chess''), the first comprehensive manual of chess theory.

The first modern chess tournament was organized by [[Howard Staunton]], a leading English chess player, and was [[London 1851 chess tournament|held in London in 1851]]. It was won by the German [[Adolf Anderssen]], who was hailed as the leading chess master. His energetic attacking style was [[Romantic chess|typical for the time]].<ref>{{cite web |url=http://worldchessnetwork.com/English/chessHistory/salute/matchesTournaments/london1851.php |title=London, 1851 |last=Parr|first=Larry |publisher=World Chess Network |access-date=26 November 2008 |url-status=dead |archive-url=https://web.archive.org/web/20031004035110/http://worldchessnetwork.com/English/chessHistory/salute/matchesTournaments/london1851.php |archive-date=4 October 2003  |author-link=Larry Parr (editor)}}</ref><ref>{{harvp|Hartston|1985|p=36}}</ref> Sparkling games like Anderssen's [[Immortal Game]] and [[Evergreen Game]] or [[Paul Morphy|Morphy's]] "[[Morphy versus the Duke of Brunswick and Count Isouard|Opera Game]]" were regarded as the highest possible summit of the art of chess.<ref>{{harvp|Burgess|Nunn|Emms|2004|p=14}}</ref> Deeper insight into the nature of chess came with the American [[Paul Morphy]], an extraordinary [[chess prodigy]]. Morphy won against all important competitors (except Staunton, who refused to play), including Anderssen, during his short chess career between 1857 and 1863.<ref>{{harvp|Shibut|2004}}</ref>

===1873–1945: Birth of a sport===
[[File:Wilhelm Steinitz2.jpg|thumb|right|upright 0.8|[[Wilhelm Steinitz]], the first official [[World Chess Champion]], from 1886 to 1894]]
{{Chess diagram small
|tright
|Rubinstein vs. Nimzowitsch, 1925
|rd|nd|  |qd|kd|  |  |rd  
|pd|bd|  |pd|pd|pd|bd|pd
|  |  |  |  |  |nd|pd|  
|  |  |pd|  |  |  |  |  
|  |  |pl|  |  |  |  |  
|  |pl|  |  |  |nl|pl|  
|pl|bl|  |  |pl|pl|bl|pl
|rl|nl|  |ql|kl|  |  |rl  
|Nimzowitsch later commented: "Each side castles now with a clear conscience, for not even the most hypermodern pair of masters can produce more than four fianchettoed Bishops!"<ref>{{harvp|Nimzowitsch|1925|p=140}}</ref>
}}
[[Prague]]-born [[Wilhelm Steinitz]] laid the foundations for a scientific approach to the game, the art of breaking a position down into components<ref>{{harvp|Kasparov|2003a|p=6}}</ref> and preparing correct plans.<ref>{{harvp|Kasparov|2003a|p=11}}</ref> In addition to his theoretical achievements, Steinitz founded an important tradition: his triumph over the leading German master [[Johannes Zukertort]] in 1886 is regarded as the first official [[World Chess Championship]]. This win marked a stylistic transition at the highest levels of chess from an attacking, tactical style predominant in the Romantic era to a more positional, strategic style introduced to the chess world by Steinitz. Steinitz lost his crown in 1894 to a much younger player, the German mathematician [[Emanuel Lasker]], who maintained this title for 27 years, the longest tenure of any world champion.<ref>{{harvp|Kasparov|2003a|p=117}}</ref>

After the end of the 19th century, the number of master tournaments and matches held annually quickly grew. The first [[Chess Olympiad|Olympiad]] was held in Paris in 1924, and [[FIDE]] was founded initially for the purpose of organizing that event. In 1927, the [[Women's World Chess Championship]] was established; the first to hold the title was Czech-English master [[Vera Menchik]].<ref>{{cite web |url=http://www.chessgames.com/perl/chessplayer?pid=13277 |title=Vera Menchik |website=[[Chessgames.com]] |access-date=26 November 2008 |url-status=live |archive-url=https://web.archive.org/web/20081026031307/http://www.chessgames.com/perl/chessplayer?pid=13277 |archive-date=26 October 2008}}</ref>

A prodigy from Cuba, [[José Raúl Capablanca]], known for his skill in endgames, won the World Championship from Lasker in 1921. Capablanca was undefeated in tournament play for eight years, from 1916 to 1924. His successor (1927) was the Russian-French [[Alexander Alekhine]], a strong attacking player who died as the world champion in 1946. Alekhine briefly lost the title to Dutch player [[Max Euwe]] in 1935 and regained it two years later.<ref>{{harvp|Kasparov|2003b|p=9}}</ref>

In the [[interwar period]], chess was revolutionized by the new theoretical school of so-called [[Hypermodernism (chess)|hypermodernists]] like [[Aron Nimzowitsch]] and [[Richard Réti]]. They advocated controlling the {{chessgloss|center}} of the board with distant pieces rather than with pawns, thus inviting opponents to occupy the center with pawns, which become objects of attack.<ref>{{harvp|Hooper|Whyld|1992|p=178}}</ref> Among the innovations popularized by hypermodernists was the [[fianchetto]]: the development of bishops away from, rather than towards, the center, onto the b- and g-files.

===1945–1990: Post-World War II era===
[[File:Mikhail Botvinnik 1962.jpg|thumb|left|[[Mikhail Botvinnik]], the first post-war World Champion]]
After the death of Alekhine, a new World Champion was sought. FIDE, which has controlled the title since then, ran a tournament of elite players. The winner of the [[World Chess Championship 1948|1948 tournament]] was Russian [[Mikhail Botvinnik]]. In 1950, FIDE established a system of titles, conferring the title of [[Grandmaster (chess)|Grandmaster]] on 27 players. (Some sources state that, in 1914, the title of chess Grandmaster was first formally conferred by Tsar [[Nicholas II of Russia]] to Lasker, Capablanca, Alekhine, [[Siegbert Tarrasch|Tarrasch]], and [[Frank Marshall (chess player)|Marshall]], but this is a disputed claim.{{refn|This is stated in ''The Encyclopaedia of Chess'' (1970, p. 223) by [[Anne Sunnucks]], but is disputed by [[Edward Winter (chess historian)]] in his [http://www.chesshistory.com/winter/winter38.html Chess Notes 5144 and 5152].|group=note}})

Botvinnik started an era of [[Soviet Union|Soviet]] dominance in the chess world, which mainly through the Soviet government's politically inspired efforts to demonstrate intellectual superiority over the West<ref>{{Cite thesis|title=Storming Fortresses: A Political History Of Chess In The Soviet Union, 1917-1948|url=https://escholarship.org/uc/item/0s71f0cw|publisher=UC Santa Cruz|date=2013|language=en|first=Michael Andrew|last=Hudson|access-date=19 April 2021|archive-date=25 April 2021|archive-url=https://web.archive.org/web/20210425094201/https://escholarship.org/uc/item/0s71f0cw|url-status=live}}</ref><ref>{{Cite web|title=The match of the century|url=https://www.adamsmith.org/blog/the-match-of-the-century|access-date=2021-09-08|website=Adam Smith Institute|date=September 2019 |language=en-GB|archive-date=8 September 2021|archive-url=https://web.archive.org/web/20210908234912/https://www.adamsmith.org/blog/the-match-of-the-century|url-status=live}}</ref> stood almost uninterrupted for more than a half-century. Until the [[dissolution of the Soviet Union]], there was only one non-Soviet champion, American [[Bobby Fischer]] (champion 1972–1975).<ref>{{harvp|Kasparov|2003b|pp=7–8}}</ref> Botvinnik also revolutionized [[Chess theory#Opening theory|opening theory]]. Previously, Black strove for equality, attempting to neutralize White's [[first-move advantage in chess|first-move advantage]]. As Black, Botvinnik strove for the initiative from the beginning.<ref>{{harvp|Kasparov|2003b|p=7}}</ref> In the previous informal system of World Championships, the current champion decided which challenger he would play for the title and the challenger was forced to seek sponsors for the match. FIDE set up a new system of qualifying tournaments and matches. The world's strongest players were seeded into [[Interzonal]] tournaments, where they were joined by players who had qualified from Zonal tournaments. The leading finishers in these Interzonals would go through the "[[Candidates Tournament|Candidates]]" stage, which was initially a tournament, and later a series of knockout matches. The winner of the Candidates would then play the reigning champion for the title. A champion defeated in a match had a right to play a rematch a year later. This system operated on a three-year cycle. Botvinnik participated in championship matches over a period of fifteen years. He won the world championship tournament in 1948 and retained the title in tied matches in 1951 and 1954. In 1957, he lost to [[Vasily Smyslov]], but regained the title in a rematch in 1958. In 1960, he lost the title to the 23-year-old Latvian prodigy [[Mikhail Tal]], an accomplished [[Chess tactics|tactician]] and attacking player who is widely regarded as one of the most creative players ever,<ref>{{Cite web|last=Pete (Pete)|title=The 12 Most Interesting Chess Players Ever|url=https://www.chess.com/article/view/the-12-most-interesting-chess-players-ever|access-date=2021-04-19|website=Chess.com|date=28 April 2018 |language=en-US|archive-date=19 April 2021|archive-url=https://web.archive.org/web/20210419131201/https://www.chess.com/article/view/the-12-most-interesting-chess-players-ever|url-status=live}}</ref> hence his nickname "the magician from Riga". Botvinnik again regained the title in a rematch in 1961.

[[File:Bobby Fischer 1960 in Leipzig.jpg|thumb|left|[[Bobby Fischer]], World Champion from 1972 to 1975]]
Following the 1961 event, FIDE abolished the automatic right of a deposed champion to a rematch, and the next champion, Armenian [[Tigran Petrosian]], a player renowned for his defensive and positional skills, held the title for two cycles, 1963–1969. His successor, [[Boris Spassky]] from Russia (champion 1969–1972), won games in both positional and sharp tactical style.<ref>{{harvp|Kasparov|2003b|p=8}}; {{harvp|Kasparov|2004a|pp=5–6}}</ref> The next championship, the so-called [[World Chess Championship 1972|Match of the Century]], saw the first non-Soviet challenger since World War II, American [[Bobby Fischer]]. Fischer defeated his opponents in the [[Candidates Tournament|Candidates]] matches by unheard-of margins, and convincingly defeated Spassky for the world championship. The match was followed closely by news media of the day, leading to a surge in popularity for chess; it also held significant political importance at the height of the [[Cold War]], with the match being seen by both sides as a [[Microcosm–macrocosm analogy|microcosm]] of the conflict between East and West.<ref>{{Cite magazine|title=How chess became a pawn in Russia's political war games|language=en-GB|magazine=Wired UK|url=https://www.wired.co.uk/article/world-chess-championship-2018-london-carlsen-vs-caruana|access-date=2021-09-08|issn=1357-0978|archive-date=8 September 2021|archive-url=https://web.archive.org/web/20210908234912/https://www.wired.co.uk/article/world-chess-championship-2018-london-carlsen-vs-caruana|url-status=live}}</ref> In 1975, however, Fischer refused to defend his title against Soviet [[Anatoly Karpov]] when he was unable to reach agreement on conditions with FIDE, and Karpov obtained the title by default.<ref>{{harvp|Kasparov|2004b|pp=5–6}}</ref> Fischer modernized many aspects of chess, especially by extensively preparing openings.<ref>{{harvp|Kasparov|2003a|p=8}}</ref>

Karpov defended his title twice against [[Viktor Korchnoi]] and dominated the 1970s and early 1980s with a string of tournament successes.<ref>{{harvp|Kasparov|2004b|pp=5–6}}; {{harvp|Kasparov|2006|pp=5–6}}</ref> In the [[1984 World Chess Championship]], Karpov faced his toughest challenge to date, the young [[Garry Kasparov]] from [[Baku]], [[Soviet Azerbaijan]]. The match was aborted in controversial circumstances after 5 months and 48 games with Karpov leading by 5 wins to 3, but evidently exhausted; many commentators believed Kasparov, who had won the last two games, would have won the match had it continued. Kasparov won the [[1985 World Chess Championship|1985 rematch]]. Kasparov and Karpov contested three further closely fought matches in 1986, 1987 and 1990, Kasparov winning them all.<ref>{{harvp|Keene|1993|p=16}}</ref> Kasparov became the dominant figure of world chess from the mid-1980s until his retirement from competition in 2005.

====Beginnings of chess technology====
Chess-playing computer programs (later known as [[chess engines]]) began to appear in the 1960s. In 1970, the first major computer chess tournament, the [[North American Computer Chess Championship]], was held, followed in 1974 by the first [[World Computer Chess Championship]]. In the late 1970s, dedicated home chess computers such as Fidelity Electronics' ''[[Chess Challenger]]'' became commercially available, as well as software to run on home computers. The overall standard of computer chess was low, however, until the 1990s.

The first [[endgame tablebases]], which provided [[perfect play]] for relatively simple endgames such as king and rook versus king and bishop, appeared in the late 1970s. This set a precedent to the complete six- and seven-piece tablebases that became available in the 2000s and 2010s respectively.<ref>{{Cite web|date=2018-03-16|title=Endgame tablebases: A short history|url=https://en.chessbase.com/post/endgame-tablebases-a-short-history|access-date=2021-04-19|website=ChessBase News|language=en|archive-date=20 April 2021|archive-url=https://web.archive.org/web/20210420013702/https://en.chessbase.com/post/endgame-tablebases-a-short-history|url-status=live}}</ref>

Some of the earliest [[Chess database|chess databases]], which are collections of chess games searchable by move and position, include [[Ken Thompson]] and [[Joseph Henry Condon|Joe Condon]]'s king-queen versus king-rook chess database. They were used for testing early chess engines like [[Belle (chess machine)|Belle]]. It won the [[Association for Computing Machinery|ACM]] [[North American Computer Chess Championship]] five times and the 1980 [[World Computer Chess Championship]].<ref>{{Cite web |last=Friedel |first=Frederic |date=2020-01-04 |title=Ken Thompson: Moscow adventures (1) |url=https://en.chessbase.com/post/ken-thompson-moscow-adventures-1 |access-date=2025-10-06 |website=Chess News |language=en}}</ref> The first commercial chess database was introduced by the German company [[ChessBase]] in 1987.<ref>{{Cite web |date=2011-05-19 |title=ChessBase is 25 |url=https://en.chessbase.com/post/chebase-is-25-everything-25-off-in-our-shop |access-date=2025-02-04 |website=Chess News |language=en}}</ref> Databases containing millions of chess games have since had a profound effect on opening theory and other areas of chess research.

Digital [[chess clocks]] were invented in 1973, though they did not become commonplace until the 1990s. Digital clocks allow for time controls involving [[Time control#Increment and delay methods|increments and delays]].

===1990–present: Rise of computers and online chess===

====Technology====
The [[Internet]] enabled [[online chess]] as a new medium of playing, with [[chess servers]] allowing users to play other people from different parts of the world in real time. The first such server, known as [[Internet Chess Server]] (ICS), was developed at the University of Utah in 1992. ICS formed the basis for the first commercial chess server, the [[Internet Chess Club]], which was launched in 1995, and for other early chess servers such as [[Free Internet Chess Server]] (FICS). Since then, many other platforms have appeared, and online chess began to rival over-the-board chess in popularity.<ref>{{cite web|last1=McClain|first1=Dylan Loeb|date=14 March 2010|title=Wherever You Are, a Game Is Just a Point and Click Away|url=https://www.nytimes.com/2010/03/14/crosswords/chess/14chess.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2010/03/14/crosswords/chess/14chess.html |archive-date=2022-01-01 |url-access=limited|access-date=10 January 2021|website=The New York Times}}{{cbignore}}</ref><ref>{{cite web | title=Internet helps to speed up growth of chess around the world | website=Financial Times | url=https://www.ft.com/content/d61a112a-524a-11e5-b029-b9d50a74fd14 | date=October 7, 2015 | last1=Thomson | first1=Adam | access-date=April 22, 2021 | archive-date=20 April 2021 | archive-url=https://web.archive.org/web/20210420013702/https://www.ft.com/content/d61a112a-524a-11e5-b029-b9d50a74fd14 | url-status=live }}</ref> During the 2020 [[COVID-19 pandemic]], the isolation ensuing from [[quarantine]]s imposed in many places around the world, combined with the success of the popular [[Netflix]] show ''[[The Queen's Gambit (miniseries)|The Queen's Gambit]]'' and other factors such as the popularity of online tournaments (notably [[PogChamps]]) and chess [[Twitch (service)|Twitch]] streamers, resulted in a surge of popularity not only for online chess, but for the game of chess in general; this phenomenon has been referred to in the media as the 2020 online chess boom.<ref>{{Cite web|date=2020-11-29|title='It's electrifying': chess world hails Queen's Gambit-fuelled boom|url=http://www.theguardian.com/sport/2020/nov/29/chess-world-hails-queens-gambit-fuelled-boom|access-date=2021-04-19|website=The Guardian|language=en|archive-date=10 March 2021|archive-url=https://web.archive.org/web/20210310133353/https://www.theguardian.com/sport/2020/nov/29/chess-world-hails-queens-gambit-fuelled-boom|url-status=live}}</ref><ref>{{Cite news|last=Dottle|first=Rachael|title=The Chess Boom Goes Digital After 'The Queen's Gambit'|language=en|work=Bloomberg.com|url=https://www.bloomberg.com/graphics/2020-chess-boom/|access-date=2021-04-19|archive-date=17 April 2021|archive-url=https://web.archive.org/web/20210417174425/https://www.bloomberg.com/graphics/2020-chess-boom/|url-status=live}}</ref>

[[Computer chess]] has also seen major advances. By the 1990s, chess engines could consistently defeat most amateurs, and in 1997 [[Deep Blue (chess computer)|Deep Blue]] defeated World Champion Garry Kasparov in [[Deep Blue versus Garry Kasparov|a six-game match]], starting an era of computer dominance at the highest level of chess. In the 2010s, engines significantly stronger than even the best human players became accessible for free on a number of [[Personal computer|PC]] and [[Mobile phone|mobile]] platforms, and free engine analysis became a commonplace feature on internet chess servers. An adverse effect of the easy availability of engine analysis on hand-held devices and personal computers has been the rise of [[Chess cheating|computer cheating]], which has grown to be a major concern in both over-the-board and online chess.<ref>{{Cite web|last=Team (CHESScom)|first=Chess com|title=About Online Chess Cheating|url=https://www.chess.com/article/view/online-chess-cheating|access-date=2021-04-20|website=Chess.com|date=15 August 2020 |language=en-US|archive-date=20 April 2021|archive-url=https://web.archive.org/web/20210420131449/https://www.chess.com/article/view/online-chess-cheating|url-status=live}}</ref> In 2017, [[AlphaZero]]—a [[Artificial neural network|neural network]] also capable of playing [[shogi]] and [[Go (game)|Go]]—was introduced. Since then, many chess engines based on neural network evaluation have been written, the best of which have surpassed the traditional "[[Brute-force search|brute-force]]" engines. AlphaZero also introduced many novel ideas and ways of playing the game, which affected the style of play at the top level.<ref>{{Cite news|title=Techmate: How AI rewrote the rules of chess|publisher=Financial Times|url=https://www.ft.com/content/ea707a24-f6b7-11e7-8715-e94187b3017e|url-status=live|access-date=2021-05-13|date=12 January 2018|last1=Waters|first1=Richard|archive-date=17 March 2021|archive-url=https://web.archive.org/web/20210317081158/https://www.ft.com/content/ea707a24-f6b7-11e7-8715-e94187b3017e}}</ref>

As [[endgame tablebases]] developed, they began to provide [[perfect play]] in endgame positions in which the [[Game theory|game-theoretical]] outcome was previously unknown, such as positions with king, queen and pawn against king and queen. In 1991, Lewis Stiller published a tablebase for select six-piece endgames,<ref>{{cite journal|author=L. B. Stiller|year=1991|title=Some Results from a Massively Parallel Retrograde Analysis|journal=ICCA Journal|volume=14 |issue=3 |pages=129–134 |doi=10.3233/ICG-1991-14304}}</ref><ref>See also: {{cite journal|title=Exploiting symmetry on parallel architectures|author=L. B. Stiller|journal=ICGA Journal |year=1995|volume=18 |issue=2 |pages=102–113|doi=10.3233/icg-1995-18206}}</ref> and by 2005, following the publication of [[Eugene Nalimov|Nalimov]] tablebases, all six-piece endgame positions were solved. In 2012, Lomonosov tablebases were published which solved all seven-piece endgame positions.<ref>{{cite web|author=Convekta Ltd.|title=Lomonosov Endgame Tablebases|url=http://chessok.com/?page_id=27966|access-date=20 April 2021|archive-date=1 May 2013|archive-url=https://web.archive.org/web/20130501134618/http://chessok.com/?page_id=27966|url-status=live}}</ref> Use of tablebases enhances the performance of chess engines by providing definitive results in some branches of analysis.

Previously, preparation at the professional level required an extensive chess library and several subscriptions to publications such as ''[[Chess Informant]]'' to keep up with opening developments and study opponents' games. Today, preparation at the professional level involves the use of databases containing millions of games, and engines to analyze different opening variations and prepare novelties.<ref>{{Cite web|last=Campitelli|first=Guillermo|title=How computers changed chess|url=http://theconversation.com/how-computers-changed-chess-20772|access-date=2021-04-24|website=The Conversation|date=29 November 2013 |language=en|archive-date=25 April 2021|archive-url=https://web.archive.org/web/20210425081211/https://theconversation.com/how-computers-changed-chess-20772|url-status=live}}</ref> A number of online learning resources are also available for players of all levels, such as online courses, tactics trainers, and video lessons.<ref>{{Cite web|title=Big Techday 9 - TNG Technology Consulting - Modern Chess Preparation – The Role of Computers in professional Chess|url=http://media.techcast.cloud/bigtechday9/barcelona-1615/?q=barcelona-1615|access-date=2021-04-27|website=media.techcast.cloud|archive-date=27 April 2021|archive-url=https://web.archive.org/web/20210427010714/http://media.techcast.cloud/bigtechday9/barcelona-1615/?q=barcelona-1615|url-status=live}}</ref>

Since the late 1990s, it has been possible to follow major international chess events online, the players' moves being relayed in real time. Sensory boards have been developed to enable automatic transmission of moves. Chess players will frequently run engines while watching these games, allowing them to quickly identify mistakes by the players and spot tactical opportunities. While in the past the moves have been relayed live, today chess organizers will often impose a half-hour delay as an anti-cheating measure. Technological progress made in the 1990s and the 21st century has influenced the way that chess is studied at all levels, as well as the state of chess as a [[spectator sport]]. In the mid-to-late 2010s, and especially following the 2020 online boom, it became commonplace for [[Super Grandmaster|supergrandmasters]], such as [[Hikaru Nakamura]] and [[Magnus Carlsen]], to [[livestream]] chess content on platforms such as [[Twitch (service)|Twitch]].<ref>{{Cite web|last=Brookwell|first=Ilya|title=Chess is taking over the online video game world – and both are changing from this unlikely pairing|url=http://theconversation.com/chess-is-taking-over-the-online-video-game-world-and-both-are-changing-from-this-unlikely-pairing-143790|access-date=2021-04-26|website=The Conversation|date=2 September 2020 |language=en|archive-date=27 April 2021|archive-url=https://web.archive.org/web/20210427004246/https://theconversation.com/chess-is-taking-over-the-online-video-game-world-and-both-are-changing-from-this-unlikely-pairing-143790|url-status=live}}</ref><ref>{{Cite web|date=2021-02-23|title=The Big Story|url=https://www.protocol.com/newsletters/gaming/chess-twitch-streaming?rebelltitem=1#rebelltitem1?rebelltitem=1|access-date=2021-04-20|website=Protocol — The people, power and politics of tech|language=en|archive-date=20 April 2021|archive-url=https://web.archive.org/web/20210420132231/https://www.protocol.com/newsletters/gaming/chess-twitch-streaming?rebelltitem=1#rebelltitem1?rebelltitem=1|url-status=live}}</ref> Also following the boom, online chess started being viewed as an [[esport]], with esport teams signing chess players for the first time in 2020.<ref>{{Cite web|last=Statt|first=Nick|date=2020-08-27|title=Esports giant TSM signs Hikaru Nakamura, its first pro chess player|url=https://www.theverge.com/2020/8/27/21404322/hikaru-nakamura-chess-tsm-esports-sign-contract-player-twitch|access-date=2021-04-20|website=The Verge|language=en|archive-date=20 April 2021|archive-url=https://web.archive.org/web/20210420130729/https://www.theverge.com/2020/8/27/21404322/hikaru-nakamura-chess-tsm-esports-sign-contract-player-twitch|url-status=live}}</ref> In 2025, the number of esport teams signing chess players rose considerably, after chess was added to [[Saudi Arabia]]'s [[Esports World Cup]].<ref>{{cite news |title=Magnus Carlsen trolls FIDE in Team Liquid announcement video: 'Do I have to change?' |url=https://indianexpress.com/article/sports/chess/magnus-carlsen-trolls-fide-in-team-liquid-announcement-video-do-i-have-to-change-9837163/ |access-date=15 February 2025 |work=The Indian Express |date=15 February 2025 |language=en}}</ref><ref>{{cite news |last1=Svensen |first1=Tarjei J. |title=Ding Liren Signs With Chinese Esports Team, Reveals Return To Chess |url=https://www.chess.com/news/view/ding-liren-returns-to-chess-signs-for-lgd-gaming-less-busy-year |access-date=13 February 2025 |work=Chess.com |date=13 February 2025}}</ref>

====Growth====
The number of [[Grandmaster (chess)|grandmasters]] and other chess professionals has also grown in the modern era. Kenneth Regan and Guy Haworth conducted research involving comparison of move choices by players of different levels and from different periods with the analysis of strong chess engines. They concluded that the increase in the number of grandmasters and higher Elo ratings of the top players reflect an actual increase in the average standard of play, rather than "rating inflation" or "title inflation".<ref>{{Cite journal|last1=Regan|first1=Kenneth|last2=Haworth|first2=Guy|date=2011-08-04|title=Intrinsic Chess Ratings|url=https://ojs.aaai.org/index.php/AAAI/article/view/7951|journal=Proceedings of the AAAI Conference on Artificial Intelligence|language=en|volume=25|issue=1|pages=834–839 |doi=10.1609/aaai.v25i1.7951 |s2cid=15489049 |issn=2374-3468|access-date=20 April 2021|archive-date=20 April 2021|archive-url=https://web.archive.org/web/20210420130735/https://ojs.aaai.org/index.php/AAAI/article/view/7951|url-status=live|doi-access=free}}</ref>

Organized chess even for young children has become common. FIDE holds world championships for age levels down to 8 years old. The largest tournaments, in number of players, are those held for children.<ref>{{citation |title=SuperNationals VI is the Largest Rated Tourney Ever |date=May 13, 2017 |website=Chess Life Online |url=https://new.uschess.org/news/supernationals-vi-largest-rated-tourney-ever/ |access-date=May 8, 2018 |archive-url=https://web.archive.org/web/20210429023117/https://new.uschess.org/news/supernationals-vi-largest-rated-tourney-ever |archive-date=29 April 2021 |url-status=live}}</ref>

====Professional chess====
[[File:Gukesh in 2024 (cropped).jpg|thumb|left|[[Gukesh Dommaraju]] of India, current World Champion]]
[[File:MagnusCarlsen24.jpg|thumb|right|[[Magnus Carlsen]] of Norway, top 1 FIDE ranked player since July 2011]]
In 1993, Garry Kasparov and [[Nigel Short]] broke ties with FIDE to organize their own match for the World Championship and formed a competing [[Professional Chess Association]] (PCA). From then until 2006, there were two simultaneous World Championships and respective World Champions: the PCA or "classical" champions extending the Steinitzian tradition in which the current champion plays a challenger in a series of games, and the other following FIDE's new format of many players competing in a large knockout tournament to determine the champion. Kasparov lost his PCA title in [[Classical World Chess Championship 2000|2000]] to [[Vladimir Kramnik]] of Russia.<ref>{{cite news |url=http://archives.cnn.com/2000/WORLD/europe/11/02/chess.kramnik/index.html |archive-url=https://web.archive.org/web/20060128031243/http://archives.cnn.com/2000/WORLD/europe/11/02/chess.kramnik/index.html |archive-date=28 January 2006 |title=Kramnik beats Kasparov, 2000 |access-date=4 September 2010 |publisher=CNN |date=2 November 2000}}</ref> Due to the complicated state of world chess politics and difficulties obtaining commercial sponsorships, Kasparov was never able to challenge for the title again. Despite this, he continued to dominate in top level tournaments and remained the world's [[List of FIDE chess world number ones|highest-rated player]] until his retirement from competitive chess in 2005.

The [[World Chess Championship 2006]], in which Kramnik beat the FIDE World Champion [[Veselin Topalov]], reunified the titles and made Kramnik the undisputed World Chess Champion.<ref>{{cite web |url=http://www.chessgames.com/perl/chessplayer?pid=12295 |title=Vladimir Kramnik |website=[[Chessgames.com]] |access-date=26 November 2008 |url-status=live |archive-url=https://web.archive.org/web/20081222121703/http://www.chessgames.com/perl/chessplayer?pid=12295 |archive-date=22 December 2008 |df=dmy-all}}</ref> In September 2007, he lost the title to [[Viswanathan Anand]] of India. Anand defended his title in the [[World Chess Championship 2008|revenge match of 2008]],<ref>{{cite news |title=Viswanathan Anand regains world chess title |date=30 September 2007 |work=Reuters |url=http://in.reuters.com/article/sportsNews/idINIndia-29785520070930 |access-date=13 December 2007 |url-status=dead |archive-url=https://web.archive.org/web/20071226102028/http://in.reuters.com/article/sportsNews/idINIndia-29785520070930 |archive-date=26 December 2007 |df=dmy-all}}</ref> 2010 and 2012. Magnus Carlsen defeated Anand in [[World Chess Championship 2013|2013]], defending his title in [[World Chess Championship 2014|2014]], [[World Chess Championship 2016|2016]], [[World Chess Championship 2018|2018]], and [[World Chess Championship 2021|2021]], whereafter he announced that he would not defend his title a fifth time. The [[World Chess Championship 2023|2023 championship]] was played between the winner and runner-up of the [[Candidates Tournament 2022]]: [[Ian Nepomniachtchi]] of Russia and [[Ding Liren]] of China. Ding beat Nepomniachtchi, making him the world champion.<ref name="WCC2023" /> In [[World Chess Championship 2024|2024]], [[Gukesh Dommaraju]] of India beat Ding. Carlsen has however remained the world's highest-rated player.
{{clear left}}

==Connections to other fields==

===Arts and humanities===
{{Main|Chess in the arts}}

In the [[Middle Ages]] and during the [[Renaissance]], chess was a part of [[nobility|noble]] culture; it was used to teach war strategy and was dubbed the "[[Chess or the King's Game|King's Game]]".<ref>{{harvp|Vale|2001|pp=170–199}}</ref> Gentlemen are "to be meanly seene in the play at Chestes", says the overview at the beginning of [[Baldassare Castiglione]]'s ''[[The Book of the Courtier]]'' (1528, English 1561 by Sir Thomas Hoby), but chess should not be a gentleman's main passion. Castiglione explains it further:
[[File:Meister der Manessischen Liederhandschrift 004.jpg|thumb|Noble chess players, Germany, {{circa|1320}}]]
{{blockquote|And what say you to the game at chestes? It is {{sic|truely|hide=y}} an honest kynde of enterteynmente and wittie, quoth Syr Friderick. But me think it hath a fault, whiche is, that a man may be to couning at it, for who ever will be excellent in the playe of chestes, I beleave he must beestowe much tyme about it, and applie it with so much study, that a man may assoone learne some noble scyence, or compase any other matter of importaunce, and yet in the ende in beestowing all that laboure, he knoweth no more but a game. Therfore in this I beleave there happeneth a very rare thing, namely, that the meane is more commendable, then the excellency.<ref>{{cite book |url=http://darkwing.uoregon.edu/~rbear/courtier/courtier2.html |archive-url=https://web.archive.org/web/20000818234955/http://darkwing.uoregon.edu/~rbear/courtier/courtier2.html |url-status=dead |archive-date=18 August 2000 |title=The Second Book of the Courtier |author=Count Bladessar Castilio |translator=Sir Thomas Hoby |editor=Walter Raleigh |publisher=David Nutt |location=London |date=1900 |access-date=7 May 2010 |orig-year=1561}}</ref>}}

Some of the elaborate chess sets used by the aristocracy at least partially survive, such as the [[Lewis chessmen]].

Chess was often used as a basis of sermons on [[morality]]. An example is ''Liber de moribus hominum et officiis nobilium sive super ludo scacchorum'' ('Book of the customs of men and the duties of nobles or the Book of Chess'), written by an Italian [[Order of Preachers|Dominican]] friar [[Jacobus de Cessolis]] {{circa|1300}}. This book was one of the most popular of the Middle Ages.<ref>{{harvp|Olmert|1996|p=127}}</ref> The work was translated into many other languages (the first printed edition was published at Utrecht in 1473) and was the basis for [[William Caxton]]'s ''The Game and Playe of the Chesse'' (1474), one of the first books printed in English.<ref>{{Cite book|chapter=§3. The first book printed in English — "The Recuyell of the Histories of Troy" | title= XIII. The Introduction of Printing into England and the Early Work of the Press. | volume= 2. The End of the Middle Ages | publisher= The Cambridge History of English and American Literature: An Encyclopedia in Eighteen Volumes. 1907–21|chapter-url=https://www.bartleby.com/212/1303.html|access-date=2022-12-29|via= Bartleby|archive-date=15 August 2022|archive-url=https://web.archive.org/web/20220815001313/https://www.bartleby.com/212/1303.html|url-status=live | author = E. Gordon Duff | date= 1907}}</ref> Different chess pieces were used as metaphors for different classes of people, and human duties were derived from the rules of the game or from visual properties of the chess pieces:<ref>{{harvp|Adams|2006}}</ref>

{{blockquote|The knyght ought to be made alle armed upon an hors in suche wyse that he haue an helme on his heed and a spere in his ryght hande/ and coueryd wyth his sheld/ a swerde and a mace on his lyft syde/ Cladd wyth an hawberk and plates to fore his breste/ legge harnoys on his legges/ Spores on his heelis on his handes his gauntelettes/ his hors well broken and taught and apte to bataylle and couerid with his armes/ whan the knyghtes ben maad they ben bayned or bathed/ that is the signe that they shold lede a newe lyf and newe maners/ also they wake alle the nyght in prayers and orysons vnto god that he wylle gyue hem grace that they may gete that thynge that they may not gete by nature/ The kynge or prynce gyrdeth a boute them a swerde in signe/ that they shold abyde and kepe hym of whom they take theyr dispenses and dignyte.<ref>{{Cite book |author1-last=Caxton | author1-first= William 
| author2-last=Jacobus |author2-first=de Cessolis
|editor= William Edward Armytage Axon | orig-date= 1474
|url=http://www.gutenberg.org/ebooks/10672 |title=The Game and Playe of the Chesse |publisher=Project Gutenberg |access-date=20 May 2010 |date=January 2004 |archive-url=https://web.archive.org/web/20090924213005/http://www.gutenberg.org/etext/10672 |archive-date=24 September 2009 |url-status=live}}</ref>}}

Known in the circles of clerics, students, and merchants, chess entered into the popular culture of the Middle Ages. An example is the 209th song of [[Carmina Burana]] from the 13th&nbsp;century, which starts with the names of chess pieces, ''Roch, pedites, regina...''<ref>{{cite web |url=http://www.fh-augsburg.de/~harsch/Chronologia/Lspost13/CarminaBurana/bur_cpo2.html |title=Carmina potoria |publisher=Bibliotheca Augustana |access-date=26 November 2008 |url-status=live |archive-url=https://web.archive.org/web/20071229151500/http://www.fh-augsburg.de/~harsch/Chronologia/Lspost13/CarminaBurana/bur_cpo2.html |archive-date=29 December 2007}}</ref> The game of chess, at times, has been discouraged by various religious authorities in Middle Ages: Jewish,<ref>{{Cite encyclopedia|title=Chess | author1 = Joseph Jacobs | author2= A. Porter |url=https://www.jewishencyclopedia.com/articles/4314-chess|access-date=2022-12-29|encyclopedia =[[The Jewish Encyclopedia]]|archive-date=29 December 2022|archive-url=https://web.archive.org/web/20221229064440/https://www.jewishencyclopedia.com/articles/4314-chess|url-status=live}}</ref> Catholic and [[Eastern Orthodox Church|Orthodox]].<ref>{{harvp|Murray|1985|pp=166–167, 410}}</ref> Some Muslim authorities prohibited it even recently, for example [[Ruhollah Khomeini]] in 1979 and [[Abdul-Aziz ibn Abdullah Al ash-Sheikh|Abdul-Aziz ash-Sheikh]] even later.<ref name="Forbidden">{{cite news |url=https://www.theguardian.com/world/2016/jan/21/chess-forbidden-in-islam-rules-saudi-arabia-grand-mufti|last1=Shaheen|first1=Kareem|title=Chess forbidden in Islam, rules Saudi mufti, but issue not black and white |work=The Guardian |date=21 January 2016|access-date=1 April 2019 |archive-url=https://web.archive.org/web/20160213200335/http://www.theguardian.com/world/2016/jan/21/chess-forbidden-in-islam-rules-saudi-arabia-grand-mufti |archive-date=13 February 2016 |url-status=live}}</ref>

During the [[Age of Enlightenment]], chess was viewed as a means of self-improvement. [[Benjamin Franklin]], in his article "[[The Morals of Chess]]" (1786), wrote:
{{blockquote|
The Game of Chess is not merely an idle amusement; several very valuable qualities of the mind, useful in the course of human life, are to be acquired and strengthened by it, so as to become habits ready on all occasions; for life is a kind of Chess, in which we have often points to gain, and competitors or adversaries to contend with, and in which there is a vast variety of good and ill events, that are, in some degree, the effect of prudence, or the want of it. By playing at Chess then, we may learn:

'''I. Foresight''', which looks a little into futurity, and considers the consequences that may attend an action ...

'''II. Circumspection''', which surveys the whole Chess-board, or scene of action: – the relation of the several Pieces, and their situations ...

'''III. Caution''', not to make our moves too hastily ...<ref>{{harvp|Franklin|2003}} [1786], p. 289</ref>
}}

[[File:Red King sleeping.jpg|thumb|right|upright 1.1|''[[Through the Looking-Glass]]'': the Red King is snoring. Illustration by Sir [[John Tenniel]].]]
Chess was occasionally criticized in the 19th century as a waste of time.<ref>{{cite web |website=Medium|url=https://medium.com/message/why-chess-will-destroy-your-mind-78ad1034521f |title=Why Chess Will Destroy Your Mind |first=Clive |last=Thompson |date=22 May 2014 |url-status=live |archive-url=https://web.archive.org/web/20170901152810/https://medium.com/message/why-chess-will-destroy-your-mind-78ad1034521f |archive-date=1 September 2017}}</ref><ref>{{cite web |url=https://www.techdirt.com/articles/20140613/08020527566/that-time-when-people-thought-playing-chess-would-make-you-violent.shtml |title=That Time When People Thought Playing Chess Would Make You Violent |website=TechDirt|last1=Geigner|first1=Timothy|date=20 June 2014 |url-status=live |archive-url=https://web.archive.org/web/20170324191000/https://www.techdirt.com/articles/20140613/08020527566/that-time-when-people-thought-playing-chess-would-make-you-violent.shtml |archive-date=24 March 2017}}</ref>

Chess is taught to children in schools around the world today. Many schools host chess clubs, and there are many scholastic tournaments specifically for children. Tournaments are held regularly in many countries, hosted by organizations such as the [[United States Chess Federation]] and the National Scholastic Chess Foundation.<ref>{{cite web |url=http://www.nscfchess.org/nscfmiss.html |archive-url=https://web.archive.org/web/20091230140133/http://www.nscfchess.org/nscfmiss.html |archive-date=30 December 2009 |title=National Scholastic Chess Foundation |access-date=30 December 2009}}</ref>

Chess is many times depicted in [[Chess in the arts and literature|the arts]]; significant works where chess plays a key role range from Thomas Middleton's ''[[A Game at Chess]]'' to ''[[Through the Looking-Glass]]'' by Lewis Carroll, to Vladimir Nabokov's ''[[The Defense]]'', to ''[[The Royal Game]]'' by Stefan Zweig. Chess has also featured in film classics such as [[Ingmar Bergman]]'s ''[[The Seventh Seal]]'', [[Satyajit Ray]]'s ''[[Shatranj Ke Khilari|The Chess Players]]'', and [[Powell and Pressburger]]'s ''[[A Matter of Life and Death (film)|A Matter of Life and Death]]''.

Chess is also present in contemporary popular culture. For example, the characters in ''[[Star Trek]]'' play a futuristic version of the game called "[[Federation (Star Trek)|Federation]] [[Tri-Dimensional Chess]]",<ref>{{Cite journal|last=Kraaijeveld|date=2000|title=Origin of chess–a phylogenetic perspective|url=http://ex.ludicum.org/publicacoes/bgsj/3.pdf#page=38|journal=Board Games Studies|volume=3|pages=39–50|via=|access-date=16 January 2021|archive-date=29 September 2020|archive-url=https://web.archive.org/web/20200929011559/http://ex.ludicum.org/publicacoes/bgsj/3.pdf#page=38|url-status=live}}</ref> and "[[Wizard's Chess]]" is played in J.K. Rowling's ''[[Harry Potter]]''.<ref name="Mayes-Elma2006">{{cite book|author=Ruthann Mayes-Elma|url=https://books.google.com/books?id=LiWrXUHgnL8C&pg=PA95|title=Females and Harry Potter: Not All that Empowering|publisher=Rowman & Littlefield|year=2006|isbn=978-0-7425-3779-8|pages=95–|access-date=16 January 2021|archive-date=13 August 2021|archive-url=https://web.archive.org/web/20210813113441/https://books.google.com/books?id=LiWrXUHgnL8C&pg=PA95|url-status=live}}</ref>

===Mathematics===
{{See also|Mathematical chess problem|Solving chess}}
The game structure and nature of chess are related to several branches of mathematics. Many [[combinatorics|combinatorical]] and [[topology|topological]] problems connected to chess, such as the [[knight's tour]] and the [[eight queens puzzle]], have been known for hundreds of years.

[[File:Knight's tour.svg|thumb|upright 0.8|Mathematicians [[Euler]], [[Adrien-Marie Legendre|Legendre]], [[de Moivre]], and [[Vandermonde]] studied the [[knight's tour]].]]
The number of legal positions in chess is estimated to be {{thinspace|(4.59|±|0.38)|×|10<sup>44</sup>}} with a 95% confidence level,<ref>{{cite web |title=Chess Position Ranking |author=John Tromp |website=[[GitHub]] | year=2021 | url=https://github.com/tromp/ChessPositionRanking | url-status=live|archive-url=https://web.archive.org/web/20210808152713/https://github.com/tromp/ChessPositionRanking |archive-date=8 August 2021 }}</ref> with a [[game-tree complexity]] of approximately 10<sup>123</sup>. The game-tree complexity of chess was first calculated by [[Claude Shannon]] as 10<sup>120</sup>, a number known as the [[Shannon number]].<ref>{{cite web|title=Evolution of the Chess Robot: Brute force Wins|first=Jonathan|last=Babb|publisher=Massachusetts Institute of Technology|date=January 10, 1996|url=http://groups.csail.mit.edu/cag/pub/papers/jbabb-area.ps.Z|access-date=21 February 2023|archive-date=21 February 2023|archive-url=https://web.archive.org/web/20230221064724/http://groups.csail.mit.edu/cag/pub/papers/jbabb-area.ps.Z|url-status=live}}</ref> An average position typically has thirty to forty possible moves, but there may be as few as zero (in the case of checkmate or stalemate) or (in a constructed position) as many as 218.<ref>{{cite web |url=http://www.chessbox.de/Compu/schachzahl2_e.html |archive-url=https://web.archive.org/web/20070613072827/http://www.chessbox.de/Compu/schachzahl2_e.html |archive-date=13 June 2007 |publisher=ChessBox.de |title=The biggest Number of simultaneous possible legal Moves |url-status=dead}}</ref>

In 1913, [[Ernst Zermelo]] used chess as a basis for his theory of game strategies, which is considered one of the predecessors of [[game theory]].<ref>Zermelo, Ernst (1913), Uber eine Anwendung der Mengenlehre auf die Theorie des Schachspiels, Proceedings of the Fifth International Congress of Mathematicians 2, 501–04. Cited from Eichhorn, Christoph: Der Beginn der Formalen Spieltheorie: Zermelo (1913), [http://www.mathematik.uni-muenchen.de/~spielth/artikel/Zermelo.pdf Uni-Muenchen.de] {{webarchive|url=https://web.archive.org/web/20070612134609/http://www.mathematik.uni-muenchen.de/~spielth/artikel/Zermelo.pdf |date=12 June 2007 }}. Retrieved 23 March 2007.</ref> [[Zermelo's theorem (game theory)|Zermelo's theorem]] states that it is possible to [[Solving chess|solve chess]], i.e. to determine with certainty the outcome of a perfectly played game (either White can force a win, or Black can force a win, or both sides can force at least a draw).<ref>{{cite web |url=http://www.gap-system.org/~history/Projects/MacQuarrie/Chapters/Ch4.html |title=Fundamentals |work=gap-system.org |url-status=dead |archive-url=https://web.archive.org/web/20110607183513/http://www.gap-system.org/~history/Projects/MacQuarrie/Chapters/Ch4.html |archive-date=7 June 2011}}</ref> With 10<sup>43</sup> legal positions in chess, however, it will take an impossibly long time to compute a perfect strategy with any feasible technology.<ref>{{cite book |title=Encyclopedia of Computer Science and Technology: Volume 8 |chapter=Games |page=394 |isbn=978-0-8247-2258-6 |publisher=CRC Press |year=1977}}</ref>

====Applied mathematics====
A novel methodology in [[steganography]] explores the use of chess-based covers (such as puzzles, chess problems, game reports, training documents, news articles, etc.) for concealing data within a selection of {{Chessgloss|move|moves}}, each hiding some [[bit]]s.<ref>{{cite journal |last1=Desoky |first1=Abdelrahman |last2=Younis |first2=Mohamed |title=Chestega: chess steganography methodology |journal=Security and Communication Networks |date=November 2009 |volume=2 |issue=6 |pages=555–566 |doi=10.1002/sec.99 |doi-access=free }}</ref><ref>{{cite journal |last1=Hernandez-Castro |first1=Julio C. |last2=Blasco-Lopez |first2=Ignacio |last3=Estevez-Tapiador |first3=Juan M. |last4=Ribagorda-Garnacho |first4=Arturo |title=Steganography in games: A general methodology and its application to the game of Go |journal=Computers & Security |date=February 2006 |volume=25 |issue=1 |pages=64–71 |doi=10.1016/j.cose.2005.12.001 }}</ref> Several proof-of-concept projects have been developed that convert text or files into [[binary code]], which is then converted into a series of legal chess moves, that can then be [[Decryption|decrypted]] and downloaded.<ref>{{Cite web |last=Mukherjee |first=Nayanika |date=15 September 2024 |title='I turned Lichess into Google Drive': 18yo shows how to store files, secret messages in a game of chess |url=https://indianexpress.com/article/puzzles-and-games/info/chess-games-cloud-storage-creative-coding-cryptography-brainteasers-9567020/ |access-date=28 January 2025 |newspaper=[[The Indian Express]]}}</ref>

[[Correspondence chess]] has been historically suspected of being a potential steganographic medium. [[Melville Davisson Post]] documented a [[chess problem]] that was used to create a pictorial [[cipher]] during [[World War I]].<ref>{{Cite magazine |last=Post |first=Melville Davisson |author-link=Melville Davisson Post |date=January 1918 |title=German War Ciphers |hdl=2027/uiug.30112077173703?urlappend=%3Bseq=626%3Bownerid=13510798903194481-672 |hdl-access=free |magazine=[[Everybody's Magazine]] |volume=38 |number=1 |pages=28–34 }}</ref><ref>{{Cite magazine |last=Oberhaus |first=Daniel |date=25 March 2017 |title=The Spy Who Checkmated Me: Why Postal Chess Was Banned During Wartime |url=https://www.vice.com/en/article/the-spy-who-checkmated-me-why-postal-chess-was-banned-during-wartime/ |access-date=28 January 2025 |magazine=[[Vice (magazine)|Vice]]}}</ref> During [[World War II]], extensive [[postal censorship]] was imposed on [[military personnel]] from the United States and Canada that made playing correspondence chess impossible, arising from suspicion that chess could be used to send secret messages to the enemies.<ref>{{Cite magazine |last=Dubois |first=Joan |date=September 1991 |title=Golden Knights in Review |url=https://uscf1-nyc1.aodhosting.com/CL-AND-CR-ALL/CL-ALL/1991/1991_09.pdf#page=40 |magazine=[[Chess Life]] |pages=40–45 |via=[[US Chess Federation]] |volume=46 |number=9}}</ref>

===Psychology===
There is an extensive scientific literature on chess psychology.{{refn|Chess is even called the "[[drosophila]]" of [[cognitive psychology]] and [[artificial intelligence]] (AI) studies, because it represents the domain in which expert performance has been most intensively studied and measured.<ref>{{harvp|Grabner|Stern|Neubauer|2007|pp=398–420}}</ref>|group=note}}<ref>{{harvp|de Groot|Gobet|1996}}</ref><ref>{{harvp|Gobet|de Voogt|Retschitzki|2004}}</ref><ref>{{harvp|Holding|1985}}</ref><ref>{{harvp|Saariluoma|1995}}</ref> [[Alfred Binet]] and others showed that [[knowledge]] and verbal, rather than visuospatial, ability lies at the core of expertise.<ref>{{harvp|Binet|1894}}</ref><ref>{{harvp|Robbins|Anderson|Barker|Bradley|Fearnyhough|Henson|Hudson|Baddeley|1996|pp=83–93}}</ref> In his doctoral thesis, [[Adriaan de Groot]] showed that chess masters can rapidly perceive the key features of a position.<ref>{{harvp|de Groot|1965}}</ref> According to de Groot, this [[perception]], made possible by years of practice and study, is more important than the sheer ability to anticipate moves. De Groot showed that chess masters can memorize positions shown for a few seconds almost perfectly. The ability to memorize does not alone account for chess-playing skill, since masters and novices, when faced with random arrangements of chess pieces, had equivalent recall (about six positions in each case). Rather, it is the ability to recognize patterns, which are then memorized, which distinguished the skilled players from the novices. When the positions of the pieces were taken from an actual game, the masters had almost total positional recall.<ref>Richards J. Heuer Jr. ''Psychology of Intelligence Analysis'' Center for the Study of Intelligence, Central Intelligence Agency 1999 (see [https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/psychology-of-intelligence-analysis/art6.html Chapter 3] {{webarchive|url=https://web.archive.org/web/20070912045710/https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/psychology-of-intelligence-analysis/art6.html |date=12 September 2007 }}).</ref>

More recent research has focused on [[chess as mental training]]; the respective roles of knowledge and look-ahead search; [[brain imaging]] studies of chess masters and novices; [[blindfold chess]]; the role of [[Personality psychology|personality]] and [[intelligence]] in chess skill; gender differences; and computational models of chess expertise. The role of practice and talent in the development of chess and other domains of expertise has led to much empirical investigation. Ericsson and colleagues have argued that deliberate practice is sufficient for reaching high levels of expertise in chess.<ref>{{ cite journal
| last1= Ericsson | first1= K.A.
| last2= Krampe | first2= R. Th.
| last3= Tesch-Römer | first3= C. 
| date= 1993
|url=http://www.freakonomics.com/pdf/DeliberatePractice%28PsychologicalReview%29.pdf |archive-url=https://web.archive.org/web/20060512183911/http://www.freakonomics.com/pdf/DeliberatePractice%28PsychologicalReview%29.pdf |url-status=dead |archive-date=12 May 2006 |title=The role of deliberate practice in the acquisition of expert performance | journal=Psychological Review | volume= 100 | issue= 3
| pages= 363–406| doi= 10.1037/0033-295X.100.3.363
| s2cid= 11187529
}}</ref> Recent research, however, fails to replicate their results and indicates that factors other than practice are also important.<ref>{{Cite journal |last1=Macnamara |first1=Brooke N. |last2=Maitra |first2=Megha |date=21 August 2019 |title=The role of deliberate practice in expert performance: revisiting Ericsson, Krampe & Tesch-Römer (1993) |journal=Royal Society Open Science|volume=6 |issue=8 |page=190327 |doi=10.1177/0963721411421922|pmid=31598236 |pmc=6731745 |s2cid=190327 }}</ref><ref name="Gobet-Fernand2011">Gobet, F. & Chassy, P. (in press). {{cite web |url=http://bura.brunel.ac.uk/bitstream/2438/736/1/Seasonality%20and%20chess.pdf |title=Season of birth and chess expertise. |url-status=live |archive-url=https://web.archive.org/web/20110718172434/http://bura.brunel.ac.uk/bitstream/2438/736/1/Seasonality%20and%20chess.pdf |archive-date=18 July 2011}}&nbsp;{{small|(65.8&nbsp;KB)}} ''Journal of Biosocial Science''. <br/> Gobet, F. & Campitelli, G. (2007). {{cite web |url=http://bura.brunel.ac.uk/bitstream/2438/611/1/Gobet_DevPsyc_Final.pdf |title=The role of domain-specific practice, handedness and starting age in chess. |url-status=live |archive-url=https://web.archive.org/web/20070808073144/http://bura.brunel.ac.uk/bitstream/2438/611/1/Gobet_DevPsyc_Final.pdf |archive-date=8 August 2007 |df=dmy-all}}&nbsp;{{small|(196&nbsp;KB)}} ''Developmental Psychology'', 43, 159–72. Both retrieved 2007-07-15.</ref>
For example, [[Fernand Gobet]] and colleagues have shown that stronger players started playing chess at a young age and that experts born in the Northern Hemisphere are more likely to have been born in late winter and early spring. Compared to the general population, chess players are more likely to be non-right-handed, though they found no correlation between handedness and skill.<ref name="Gobet-Fernand2011" />

A relationship between chess skill and intelligence has long been discussed in scientific literature as well as in popular culture. Academic studies that investigate the relationship date back at least to 1927.<ref>Djakow, I. N., Petrowski, N. W., & Rudik, P. A. (1927).

Psychologie des schachspiels.</ref> Although one meta-analysis and most children studies find a positive correlation between general cognitive ability and chess skill, adult studies show mixed results.<ref>{{Cite journal |date=1 November 2016 |title=The relationship between cognitive ability and chess skill: A comprehensive meta-analysis |journal=Intelligence |language=en |volume=59 |pages=72–83 |doi=10.1016/j.intell.2016.08.002 |issn=0160-2896 |last1=Burgoyne |first1=Alexander P. |last2=Sala |first2=Giovanni |last3=Gobet |first3=Fernand |last4=MacNamara |first4=Brooke N. |last5=Campitelli |first5=Guillermo |last6=Hambrick |first6=David Z. |url=http://eprints.lse.ac.uk/102241/1/INTELL_2016_117_The_Relationship_between_Cognitive_Ability_and_Chess_Skill_a_Comprehensive_Meta_Analysis.pdf |access-date=26 February 2020 |archive-date=6 May 2020 |archive-url=https://web.archive.org/web/20200506054933/http://eprints.lse.ac.uk/102241/1/INTELL_2016_117_The_Relationship_between_Cognitive_Ability_and_Chess_Skill_a_Comprehensive_Meta_Analysis.pdf |url-status=live }}</ref><ref>{{Cite journal |last1=Campitelli |first1=Guillermo |last2=Gobet |first2=Fernand |date=5 October 2011 |title=Deliberate Practice: Necessary But Not Sufficient |journal=Current Directions in Psychological Science |volume=20 |issue=5 |pages=280–285 |doi=10.1177/0963721411421922|s2cid=145572294 }}</ref>

==Online chess==
{{Main|Online chess}}

Online chess is chess played over the internet. This is done through the use of [[List of Internet chess platforms|internet chess platforms]], which use [[Elo rating system|Elo ratings]] or similar systems to pair up individual players. Online chess saw a spike in growth during the [[quarantine]]s of the [[COVID-19 pandemic]].<ref name=Ruiter>{{cite web |last1=Ruiter |first1=Chananya De |title=The Queen's Gambit And A Rise In Online Chess Playing |url=https://www.thailandtatler.com/life/queens-gambit-a-new-perspective-on-chess |website=Tatler Thailand |access-date=10 January 2021 |language=en-TH |date=16 November 2020 |archive-date=12 January 2021 |archive-url=https://web.archive.org/web/20210112150626/https://www.thailandtatler.com/life/queens-gambit-a-new-perspective-on-chess |url-status=live }}</ref><ref name="businessinsider">{{cite web |last1=Jibilian |first1=Isabella |title=Netflix's hit show 'The Queen's Gambit' inspired a chess surge — but now Chess.com is seeing a surge in cheating, too. |url=https://www.businessinsider.com/chess-website-sees-cheating-high-after-netflix-queens-gambit-surge-2020-12 |website=Business Insider |access-date=10 January 2021 |archive-date=12 January 2021 |archive-url=https://web.archive.org/web/20210112072313/https://www.businessinsider.com/chess-website-sees-cheating-high-after-netflix-queens-gambit-surge-2020-12 |url-status=live }}</ref> This can be attributed to both isolation and the popularity of [[Netflix]] miniseries ''[[The Queen's Gambit (miniseries)|The Queen's Gambit]]'', which was released in October 2020.<ref name=Ruiter/><ref name="businessinsider"/> Chess app downloads on the [[App Store (iOS/iPadOS)|App Store]] and [[Google Play Store]] rose by 63% after the show debuted.<ref name="morningbrew">{{cite web |last1=Howell |first1=Toby |title=Netflix's 'The Queen's Gambit' is Causing a Surge in Online Chess Play |url=https://www.morningbrew.com/daily/stories/2020/11/02/netflixs-queens-gambit-causing-surge-online-chess-play |website=Morning Brew |access-date=10 January 2021 |archive-date=12 January 2021 |archive-url=https://web.archive.org/web/20210112044420/https://www.morningbrew.com/daily/stories/2020/11/02/netflixs-queens-gambit-causing-surge-online-chess-play |url-status=live }}</ref> [[Chess.com]] saw more than twice as many account registrations in November as it had in previous months, and the number of games played monthly on [[Lichess]] doubled as well. There was also a demographic shift in players, with female registration on Chess.com shifting from 22% to 27% of new players.<ref>{{cite web |last1=Settembre |first1=Jeanette |title=Online chess classes see record interest amid pandemic, and after release of Netflix's 'The Queen's Gambit' |url=https://www.foxnews.com/lifestyle/chess-queens-gambit-boosting-player-interest-pandemic |website=Fox News |access-date=10 January 2021 |date=9 November 2020 |archive-date=12 January 2021 |archive-url=https://web.archive.org/web/20210112133014/https://www.foxnews.com/lifestyle/chess-queens-gambit-boosting-player-interest-pandemic |url-status=live }}</ref> [[Grandmaster (chess)|GM]] [[Maurice Ashley]] said "A boom is taking place in chess like we have never seen maybe since the Bobby Fischer days", attributing the growth to an increased desire to do something constructive during the pandemic.<ref>{{cite web |last1=Rothman |first1=David |title=Online chess makes its biggest move |url=https://www.cbsnews.com/news/online-chess-makes-its-biggest-move/ |website=www.cbsnews.com |date=November 2020 |access-date=10 January 2021 |language=en |archive-date=12 January 2021 |archive-url=https://web.archive.org/web/20210112030711/https://www.cbsnews.com/news/online-chess-makes-its-biggest-move/ |url-status=live }}</ref> [[United States Chess Federation|USCF]] Women's Program Director [[Jennifer Shahade]] stated that chess works well on the internet, since pieces do not need to be reset and [[Matchmaking (video games)|matchmaking]] is virtually instant.<ref>{{cite web |last1=Robertson |first1=Noah |title=Online chess is thriving, a calming constant in a chaotic year |url=https://www.csmonitor.com/USA/Society/2020/0820/Online-chess-is-thriving-a-calming-constant-in-a-chaotic-year |website=Christian Science Monitor |access-date=10 January 2021 |date=20 August 2020 |archive-date=11 January 2021 |archive-url=https://web.archive.org/web/20210111224133/https://www.csmonitor.com/USA/Society/2020/0820/Online-chess-is-thriving-a-calming-constant-in-a-chaotic-year |url-status=live }}</ref>

==Computer chess==
{{Main|Computer chess}}

{{See also|Human–computer chess matches|Deep Blue versus Garry Kasparov|Chess engine}}
The idea of creating a chess-playing machine dates to the 18th&nbsp;century; around 1769, the chess-playing [[automaton]] called [[Mechanical Turk|The Turk]] became famous before being exposed as a [[hoax]].<ref>{{harvp|Levitt|2000}}</ref> Serious trials based on automata, such as [[El Ajedrecista]], were too complex and limited to be useful. Since the advent of the [[digital computer]] in the 1950s, chess enthusiasts, [[computer engineer]]s, and computer scientists have built, with increasing degrees of seriousness and success, chess-playing machines and computer programs.<ref>{{harvp|Hsu|2002}}</ref> The groundbreaking paper on computer chess, "Programming a Computer for Playing Chess", was published in 1950 by [[Claude Shannon]].{{refn|[[Alan Turing]] made an attempt in 1953.<ref>{{cite web |url=http://www.turingarchive.org/browse.php/B/7 |title=Digital computers applied to games |author=Alan Turing |publisher=University of Southampton and King's College Cambridge |url-status=live |archive-url=https://web.archive.org/web/20080509054855/http://www.turingarchive.org/browse.php/B/7 |archive-date=9 May 2008 |df=dmy-all}}</ref>|group=note}} He wrote:
{{blockquote|
The chess machine is an ideal one to start with, since: (1) the problem is sharply defined both in allowed operations (the moves) and in the ultimate goal (checkmate); (2) it is neither so simple as to be trivial nor too difficult for satisfactory solution; (3) chess is generally considered to require "thinking" for skillful play; a solution of this problem will force us either to admit the possibility of a mechanized thinking or to further restrict our concept of "thinking"; (4) the discrete structure of chess fits well into the digital nature of
modern computers.<ref>Shannon, Claude E. XXII. Programming a Computer for Playing Chess. ''Philosophical Magazine'', Ser. 7, Vol. 41, No. 314 – March 1950. Available online at {{cite web |url=http://archive.computerhistory.org/projects/chess/related_materials/text/2-0%20and%202-1.Programming_a_computer_for_playing_chess.shannon/2-0%20and%202-1.Programming_a_computer_for_playing_chess.shannon.062303002.pdf |title=computerhistory.org |url-status=dead |archive-url=https://web.archive.org/web/20100706211229/http://archive.computerhistory.org/projects/chess/related_materials/text/2-0%20and%202-1.Programming_a_computer_for_playing_chess.shannon/2-0%20and%202-1.Programming_a_computer_for_playing_chess.shannon.062303002.pdf |archive-date=6 July 2010 }}&nbsp;{{small|(175&nbsp;KB)}} Retrieved 6 December 2006.</ref>
}}

[[File:RS Chess Computer.JPG|thumb|1990s chess-playing computer]]
The [[Association for Computing Machinery]] (ACM) held the first major chess tournament for computers, the [[North American Computer Chess Championship]], in September 1970. [[Chess (Northwestern University)|CHESS 3.0]], a chess program from [[Northwestern University]], won the championship. The first [[World Computer Chess Championship]], held in 1974, was won by the Soviet program [[Kaissa]]. At first considered only a curiosity, the best [[chess engine|chess playing programs]] have become extremely strong. In 1997, a computer won a chess match using classical time controls against a reigning World Champion for the first time: [[IBM|IBM's]] [[IBM Deep Blue|Deep Blue]] beat [[Garry Kasparov]] 3½–2½ (it scored two wins, one loss, and three [[draw (chess)|draws]]).<ref>{{harvp|Hsu|2002|pp=295–296}}</ref><ref>[http://researchweb.watson.ibm.com/deepblue/watch/html/c.shtml Deep Blue – Kasparov Match] {{webarchive|url=https://web.archive.org/web/20100302133413/http://researchweb.watson.ibm.com/deepblue/watch/html/c.shtml |date=2 March 2010 }}. {{em|research.ibm.com}}. Retrieved 30 November 2006.</ref> There was some controversy over [[Deep Blue versus Garry Kasparov|the match]],<ref>{{cite magazine |url=https://www.wired.com/2012/09/deep-blue-computer-bug/ |title=Did a Computer Bug Help Deep Blue Beat Kasparov? |magazine=Wired |date=28 September 2012 |last1=Finley|first1=Klint|access-date=14 May 2018 |archive-url=https://web.archive.org/web/20180515043725/https://www.wired.com/2012/09/deep-blue-computer-bug/ |archive-date=15 May 2018 |url-status=live}}</ref> and [[Human–computer chess matches|human–computer matches]] were relatively close over the next few years, until convincing computer victories in [[Human–computer chess matches#Hydra–Adams (2005)|2005]] and in [[Human–computer chess matches#Kramnik–Deep Fritz (2006)|2006]].

In 2009, a [[mobile phone]] won a [[Category (chess tournament)|category]] 6 tournament with a performance rating of 2898: chess engine [[Hiarcs]] 13 running on the mobile phone [[HTC Touch HD]] won the Copa Mercosur tournament with nine wins and one draw.<ref>{{cite web |url=https://theweekinchess.com/html/twic771.html#13 |archive-url=https://web.archive.org/web/20110930232108/https://theweekinchess.com/html/twic771.html#13 |archive-date=30 September 2011 |title=Hiarcs 13 wins Copa Mercosur |access-date=4 September 2010 |last1=Crowther|first1=Mark|website=[[The Week in Chess]]}}</ref> The best chess programs are now able to consistently beat the strongest human players, to the extent that human–computer matches no longer attract interest from chess players or the media.<ref>{{Cite web|title=20 Years Later, Humans Still No Match For Computers On The Chessboard|url=https://www.npr.org/sections/alltechconsidered/2016/10/24/499162905/20-years-later-humans-still-no-match-for-computers-on-the-chessboard|last1=Siegel|first1=Robert|date=October 24, 2016|access-date=2021-03-11|website=NPR.org|language=en|archive-date=26 November 2020|archive-url=https://web.archive.org/web/20201126080706/https://www.npr.org/sections/alltechconsidered/2016/10/24/499162905/20-years-later-humans-still-no-match-for-computers-on-the-chessboard|url-status=live}}</ref> While the [[World Computer Chess Championship]] still exists, the [[Top Chess Engine Championship]] (TCEC) is widely regarded as the unofficial world championship for chess [[chess engine|engines]].<ref>{{cite web |last=Kosteniuk |first=Alexandra |date=August 15, 2013 |title=TCEC Computer Chess Championship New Season starts August 26th |url=http://www.chessblog.com/2013/08/tcec-computer-chess-championship-new.html |archive-url=https://web.archive.org/web/20131025063745/http://www.chessblog.com/2013/08/tcec-computer-chess-championship-new.html |archive-date=October 25, 2013 |access-date=October 25, 2013 |website=Chess News Blog}}</ref><ref>{{cite web |last=Soltis |first=Andy |date=June 9, 2013 |title=Engine Super Bowl |url=https://nypost.com/2013/06/09/engine-super-bowl/ |access-date=October 25, 2013 |website=New York Post |archive-date=3 May 2016 |archive-url=https://web.archive.org/web/20160503041111/http://nypost.com/2013/06/09/engine-super-bowl/ |url-status=live }}</ref><ref>{{cite web |last=Roeder |first=Oliver |date=January 25, 2022 |title=We Taught Computers To Play Chess — And Then They Left Us Behind |url=https://fivethirtyeight.com/features/we-taught-computers-to-play-chess-and-then-they-left-us-behind/ |access-date=February 15, 2022 |website=[[Fivethirtyeight]] |archive-date=16 February 2022 |archive-url=https://web.archive.org/web/20220216055753/https://fivethirtyeight.com/features/we-taught-computers-to-play-chess-and-then-they-left-us-behind/ |url-status=live }}</ref> The current champion is [[Stockfish (chess)|Stockfish]].

With huge databases of past games and high analytical ability, computers can help players to learn chess and prepare for matches. [[Internet Chess Server]]s allow people to find and play opponents worldwide. The presence of computers and modern communication tools have raised concerns regarding [[Cheating in chess|cheating during games]].<ref>{{cite news |url=https://www.nytimes.com/2006/08/08/sports/othersports/08chess.html |title=Cheating Accusations in Mental Sports, Too |access-date=28 August 2010 |work=The New York Times |last1=McClain|first1=Dylan Loeb|date=8 August 2006 |url-status=live |archive-url=https://web.archive.org/web/20111205235525/http://www.nytimes.com/2006/08/08/sports/othersports/08chess.html |archive-date=5 December 2011}}</ref>
{{clear}}

==Related games==
[[File:Sittuyin starting position No. 8.PNG|right|thumb|[[Sittuyin]], after setup phase. Players elect their own starting setups behind the pawns.]]
Related games include:
* direct predecessors of chess, such as [[chaturanga]] and [[shatranj]];
* traditional national or regional games that share common ancestors with Western chess such as [[xiangqi]] (Chinese chess), [[shogi]] (Japanese chess), [[janggi]] (Korean chess), [[makruk|ouk chatrang]] (Cambodian chess), [[makruk]] (Thai chess), [[sittuyin]] (Burmese chess), and [[shatar]] (Mongolian chess);
In the comparison of chess with games often referred to as national forms of chess, chess may be referred to as ''Western chess'' or ''international chess''.<ref name="Parlett p276">"Western culture regards Chess as a particular game with a particular set of rules governed by an international authority (FIDE – the Fédération Internationale des Echecs). Variously known as International Chess, World Chess, Orthochess, and so on [...]" {{harvp|Parlett|1999|p=276}}</ref><ref name="Schmittberger p186">{{cite book |last=Schmittberger |first=R. Wayne |title=New Rules for Classic Games |publisher=John Wiley & Sons Inc |year=1992 |page=[https://archive.org/details/newrulesforclass00rway/page/186 186] |quote=The form of chess most people know&nbsp;– which is sometimes referred to as Western chess, orthodox chess, or orthochess&nbsp;– is itself just one of many that have been played throughout history. |isbn=978-0-471-53621-5 |url=https://archive.org/details/newrulesforclass00rway/page/186}}</ref>

===Chess variants===
{{Main|Chess variant|List of chess variants}}

[[File:Capablanca_playing_Capablanca_chess.jpg|thumb|[[José Raúl Capablanca|Capablanca]] demonstrating Capablanca chess on a 10x10 board as reported in a 1929 April issue of ''[[The Times]]'']]
There are more than two thousand published chess variants, games with similar but different rules,<ref>{{harvp|Pritchard|2000|p=8}}</ref> most of which are of relatively recent origin.<ref>Pritchard details 1,450 of them in {{cite book |last=Pritchard |first=D.B. |author-link=David Pritchard (chess player) |title=The Encyclopedia of Chess Variants |publisher=Games & Puzzles Publications |year=1994 |isbn=978-0-9524142-0-9}} "Of these, about half date from between 700 and 1970 (1,200 years!), half from the last quarter of the twentieth century." {{harvp|Parlett|1999|p=312}}</ref> 

They include modern variations employing different rules (e.g. [[losing chess]] and [[Chess960]]{{refn|In 2008 FIDE added Chess960 rules to an appendix of the Handbook.<ref name="FideLawsOfChess2009">From {{Cite web|title=Laws Historic |url=http://aekphotography.co.uk/CAA/html/laws_historic.html|access-date=2022-12-29|website=Chess Arbiters' Association|archive-date=6 July 2020|archive-url=https://web.archive.org/web/20200706060640/http://aekphotography.co.uk/CAA/html/laws_historic.html|url-status=live}}: {{Cite web|title=FIDE Laws of Chess - coming into force on 1 July 2009 |url=http://aekphotography.co.uk/CAA/Laws_of_Chess_2009.pdf|access-date=5 July 2020|website=Chess Arbiters' Association|archive-date=21 October 2020|archive-url=https://web.archive.org/web/20201021164037/http://aekphotography.co.uk/CAA/Laws_of_Chess_2009.pdf|url-status=live}}</ref> This section is now classified under "Guidelines",<ref name="FideLawsOfChess"/> indicating that the rules presented do not have the weight of FIDE law.|group=note}}), different armies (e.g. [[Dunsany's chess]]), [[Fairy piece|non-standard pieces]] (e.g. [[Knighted chess|Capablanca chess]] and [[Falcon–hunter chess]]), and different board geometries (e.g. [[hexagonal chess]] and [[infinite chess]]). In the context of chess variants, chess is commonly referred to as ''orthodox chess'', ''orthochess'', and ''classic chess''.<ref name="Parlett p276" /><ref name="Schmittberger p186" />

==See also==
* [[Glossary of chess]]
* [[Glossary of chess problems]]
* [[List of abstract strategy games]]
* [[List of chess players]]
* [[List of World Chess Championships]]
* [[Outline of chess]]
* [[Women in chess]]

==Footnotes==
{{Reflist|group=note|30em}}

==Notes==
{{Reflist}}

==References==
{{Refbegin|30em}}
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* {{Cite book |last=Binet |first=A. |year=1894 |title=Psychologie des grands calculateurs et joueurs d'échecs |language=fr |location=Paris |publisher=Hachette |oclc=287413777}}
* {{cite book |last1=Brunning |first1=Sue |last2=Yu-Ping |first2=Luk |last3=O'Connell |first3=Elisabeth R. |last4=Williams |first4=Tim |title=Silk Roads |publisher=The British Museum |publication-date=2024 |isbn=978-0-7141-2498-8}}
* {{Cite book |last=Burgess |first=Graham |title=The Mammoth Book of Chess |publisher=Carroll & Graf |year=2000 |isbn=978-0-7867-0725-6 |location=New York}}
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* {{Cite book |last=Davidson |first=Henry A. |year=1949 |title=A Short History of Chess |publisher=D. McKay Co |isbn=978-0-679-14550-9 |oclc=17340178 |location=New York}}
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* {{Cite book |last1=de Groot |first1=Adriaan D. |last2=Gobet |first2=Fernand |title=Perception and Memory in Chess: Heuristics of the Professional Eye |location=Assen, NL |publisher=Van Gorcum |year=1996 |isbn=978-90-232-2949-0}}
* {{Cite book |last=de la Villa |first=Jesús |author-link=Jesús de la Villa |title=100 Endgames You Must Know |publisher=[[New in Chess]] |year=2008 |isbn=978-90-5691-244-4}}
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* {{Cite book |last=Kasparov |first=Garry |author-link=Garry Kasparov |title=My Great Predecessors, part I |year=2003a |publisher=[[Everyman Chess]] |isbn=978-1-85744-330-1 |oclc=223602528 |location=London; Guilford, CT | title-link=My Great Predecessors}}
* {{Cite book |last=Kasparov |first=Garry |title=My Great Predecessors, part II |year=2003b |publisher=Everyman Chess |isbn=978-1-85744-342-4 |oclc=223906486 |location=London; Guilford, CT}}
* {{Cite book |last=Kasparov |first=Garry |title=My Great Predecessors, part III |year=2004a |publisher=Everyman Chess |isbn=978-1-85744-371-4 |oclc=52949851 |location=London; Guilford, CT}}
* {{Cite book |last=Kasparov |first=Garry |title=My Great Predecessors, part IV |year=2004b |publisher=Everyman Chess |isbn=978-1-85744-395-0 |oclc=52949851 |location=London; Guilford, CT}}
* {{Cite book |last=Kasparov |first=Garry |title=My Great Predecessors, part V |year=2006 |publisher=Everyman Chess |isbn=978-1-85744-404-9 |oclc=52949851 |location=London; Guilford, CT}}
* {{Cite book |last=Keene |first=Raymond |title=Gary Kasparov's Best Games |publisher=B.T. Batsford |year=1993 |isbn=978-0-7134-7296-7 |oclc=29386838 |location=London}}
* {{Cite book |last=Landsberger |first=Kurt |title=William Steinitz, Chess Champion: A Biography of the Bohemian Caesar |publisher=[[McFarland & Company]] |year=1992 |isbn=0-89950-758-1}}
* {{Cite book |last=Lasker |first=Emanuel |author-link=Emanuel Lasker |title=Lasker's Chess Primer |year=1934 |publisher=Billings (1988 reprint) |isbn=978-0-7134-6241-8 |location=London}}
* {{Cite book |last=Levitt |first=Gerald M. |title=The Turk, Chess Automaton |publisher=McFarland & Company |year=2000 |isbn=978-0-7864-0778-1 |oclc=226148928 |location=Jefferson, NC}}
* {{Cite book |last=Li |first=David H. |author-link=David H. Li |title=The Genealogy of Chess |publisher=Premier |year=1998 |isbn=978-0-9637852-2-0 |oclc=39281682 |location=Bethesda, MD}}
* {{Cite book|title=Ancient Board Games in Perspective: The Beginnings of Chess|last=Mark |first=Michael|publisher=British Museum Press|year=2007|isbn=9780714111537|location=United Kingdom}}
* {{Cite book |last=Metzner |first=Paul |title=Crescendo of the Virtuoso: Spectacle, Skill, and Self-Promotion in Paris during the Age of Revolution |publisher=University of California Press |year=1998 |isbn=978-0-520-20684-7 |oclc=185289629 |url=http://publishing.cdlib.org/ucpressebooks/view?docId=ft438nb2b6&brand=ucpress |location=Berkeley |access-date=28 August 2010 |archive-date=6 July 2010 |archive-url=https://web.archive.org/web/20100706122359/http://publishing.cdlib.org/ucpressebooks/view?docId=ft438nb2b6&brand=ucpress |url-status=live }}
* {{Cite book |last=Murray |first=H.J.R. |author-link=H. J. R. Murray |title=A History of Chess |publisher=Benjamin Press  |year=1985 |isbn=978-0-936317-01-4 |oclc=13472872 |location=Northampton, Mass. |url=https://archive.org/details/AHistoryOfChessHJRMurray/page/n33/mode/2up |orig-date=First pub. 1913 by [[Oxford University Press]] }}
* {{Cite book|last=Nimzowitsch|first=Aron|title=My System: 21st Century Edition|date=1925|publisher=Hays Pub|others=Lou Hays|isbn=1-880673-85-1|location=Dallas, Tex.|oclc=25278950}}
* {{Cite book |last=Olmert |first=Michael |year=1996 |title=Milton's Teeth and Ovid's Umbrella: Curiouser & Curiouser Adventures in History |publisher=Simon & Schuster |location=New York |isbn=978-0-684-80164-3 |url=https://archive.org/details/miltonsteethovid00olme }}
* {{cite book |last=Parlett |first=David |author-link=David Parlett |title=The Oxford History of Board Games |url=https://archive.org/details/oxfordhistoryofb0000parl |url-access=registration |publisher=[[Oxford University Press]] Inc |year=1999 |isbn=978-0-19-212998-7 }}
* {{Cite book |last=Pritchard |first=David |title=Popular Chess Variants |publisher=Batsford Chess Books |year=2000 |isbn=978-0-7134-8578-3 |oclc=44275285 |location=London}}
* {{Cite journal |last1=Robbins |first1=T.W. |year=1996 |title=Working Memory in Chess |journal=Memory & Cognition |pages=83–93 |doi=10.3758/BF03197274 |pmid=8822160 |last2=Anderson |first2=E.J. |last3=Barker |first3=D.R. |last4=Bradley |first4=A.C. |last5=Fearnyhough |first5=C. |last6=Henson |first6=R. |last7=Hudson |first7=S.R. |last8=Baddeley |first8=A.D. |volume=24 |issue=1 |s2cid=14009447 |doi-access=free }}
* {{Cite book |last=Saariluoma |first=Pertti |title=Chess Players' Thinking: A Cognitive Psychological Approach |publisher=Routledge |year=1995 |isbn=978-0-415-12079-1 |location=New York}}
* {{Cite book |last=Silman |first=Jeremy |author-link=Jeremy Silman |title=The Complete Book of Chess Strategy |publisher=Silman-James Press |year=1998 |isbn=978-1-890085-01-8 |location=Los Angeles}}
* {{Cite book |last=Shibut |first=Macon |title=Paul Morphy and the Evolution of Chess Theory |publisher=Courier Dover Publications |year=2004 |isbn=978-0-486-43574-9 |oclc=55639730 |location=New York}}
* {{Cite journal |last=Tamburro |first=Pete |date=September 2010 |title=Challenging the Ruy Lopez |journal=[[Chess Life]] |pages=18–21 }}
* {{Cite book |last=Tarrasch |first=Siegbert |author-link=Siegbert Tarrasch |title=The Game of Chess |publisher=Courier Dover Publications |year=1987 |isbn=978-0-486-25447-0 |oclc=15631832 |location=New York}}
* {{Cite book|title=Elephants and Kings: An Environmental History|last=Trautmann | first = Thomas|publisher=University of Chicago Press|year=2015|isbn=9780226264530|location=United States}}
* {{Cite book |last=Vale |first=Malcolm |title=The Princely Court: Medieval Courts and Culture in North-West Europe, 1270–1380 |publisher=Oxford University Press |year=2001 |isbn=978-0-19-926993-8 |oclc=47049906 |location=Oxford}}
* {{Cite book|title=The Sháhnáma of Firdausí: Volume VII|last=Warner |first=A.G.|publisher=Routledge|year=2000|isbn=9781136396809|location=United Kingdom}}
* {{Cite book |last=Watson |first=John |author-link=John L. Watson |title=Secrets of Modern Chess Strategy |year=1998 |publisher=[[Gambit Publications]] |isbn=978-1-901983-07-4 |location=London}}
* {{cite book |last=Weenink |first=H.G.M. |editor1=Hume, G. |editor2=White, A.C. |title=The Chess Problem |publisher=Office of The Chess Amateur |location=Stroud |year=1926 |oclc=3617028}}
* {{Cite book |last=Weissberger |first=Barbara F. |title=Isabel Rules: Qonstructing Queenship, Wielding Power |publisher=University of Minnesota Press |year=2004 |isbn=978-0-8166-4164-2 |oclc=217447754 |location=Minneapolis}}
* {{Cite book |title=Birth of the Chess Queen |isbn=978-0-06-009064-7 |last=Yalom |first=Marilyn |year=2004 |publisher=Harper Collins Publishers |location=New York}}
{{Refend}}

==Further reading==
* {{Cite book |last=Bird |first=Henry |author-link=Henry Bird (chess player) |orig-year=First published 1893 |year=2008 |title=Chess History and Reminiscences |publisher=Forgotten Books |isbn=978-1-60620-897-7}}
* {{Cite book |author=Dunnington, Angus |year=2003 |title=Chess Psychology: Approaching the Psychological Battle Both on and Off the Board |publisher=[[Everyman Chess]] |isbn=978-1-85744-326-4 |ref=none}}
* {{Cite book |author=Fine, Reuben |title=The World's Great Chess Games |publisher=Courier Dover Publications |year=1983 |isbn=978-0-486-24512-6 |oclc=9394460| author-link=Reuben Fine |ref=none}}
* {{Cite book |author=Hale, Benjamin |year=2008 |title=Philosophy Looks at Chess |publisher=[[Open Court Publishing Company]] |isbn=978-0-8126-9633-2 |ref=none}}
* {{Cite journal |last1=Ilko |first1=Krisztina |title=Chess and Race in the Global Middle Ages |journal=Speculum |date=2024 |volume=99 |issue=2 |pages=480–540 |doi=10.1086/729294}}
* {{Cite book |author=Kotov, Alexander |year=1971 |title=Think Like a Grandmaster |publisher=B.T. Batsford Ltd |isbn=978-0-7134-3160-5| author-link=Alexander Kotov |ref=none}}
* {{Cite book |author=Lasker, Emanuel |year=1960 |title=Lasker's Manual of Chess |publisher=Dover |isbn=978-0-486-20640-0| author-link=Emanuel Lasker |ref=none}}
* {{Cite book |last=Leibs |first=Andrew |year=2004 |title=Sports and Games of the Renaissance |publisher=Greenwood Publishing Group |isbn=978-0-313-32772-8 |location=Westport, CT}}
* {{Cite book |author=Mason, James |title=The Art of Chess |publisher=Dover Publications |year=1947 |isbn=978-0-486-20463-5 |oclc=45271009| author-link=James Mason (chess player) |ref=none}} (see the included supplement, "How Do You Play Chess")
* {{Cite book |author=Pachman, Luděk |year=1971 |title=Modern Chess Strategy |publisher=Dover |isbn=978-0-486-20290-7| author-link=Luděk Pachman |ref=none}}
* {{Cite book |author=Réti, Richard |year=1960 |title=Modern Ideas in Chess |publisher=Dover |isbn=978-0-486-20638-7| author-link=Richard Réti |ref=none}}
* {{Cite book |author=Rizzitano, James |title=Understanding Your Chess |publisher=Gambit Publications |year=2004 |isbn=978-1-904600-07-7 |oclc=55205602 |ref=none}}
* {{Cite book |last1=Steinitz |first1=William |last2=Landsberger |first2=Kurt |title=The Steinitz Papers: Letters and Documents of the First World Chess Champion |publisher=McFarland & Company |year=2002 |isbn=978-0-7864-1193-1 |oclc=48550929 |location=Jefferson, NC}}
* {{Cite book |last=Verwer |first=Renzo |title=Bobby Fischer for Beginners |year=2010 |publisher=[[New in Chess]] |isbn=978-90-5691-315-1 |location=Alkmaar}}
* {{Cite journal |last=Wilkinson |first=Charles K. |title=Chessmen and Chess |journal=The Metropolitan Museum of Art Bulletin |volume=New Series 1 |pages=271–79 |date=May 1943 |doi=10.2307/3257111 |issue=9 |jstor=3257111}}

==External links==
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; International organizations
* [http://www.fide.com/ FIDE]&nbsp;– [[FIDE|World Chess Federation]]
* [http://www.iccf.com/ ICCF]&nbsp;– [[International Correspondence Chess Federation]]

; News
* [http://www.chessbase.com/ Chessbase news]
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; History
* [http://www.chesshistory.com/winter/extra/factfinder.html Chesshistory.com]

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