Transposition (chess)
Template:Short description In chess, a transposition is a sequence of moves that results in a position that may also be reached by another, more common sequence of moves. Transpositions are particularly common in the opening, where a given position may be reached by different sequences of moves. Players sometimes use transpositions deliberately, to avoid variations they dislike, lure opponents into unfamiliar or uncomfortable territory or simply to worry opponents.[1][2] To transpose is to play a move that results in a transposition.
Transposition tables are an essential part of a computer chess program.
Transpositions exist in other abstract strategy games such as shogi, Go, tic-tac-toe and Hex. Template:Algebraic notation
Examples
Positions reached by different routes
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For instance, the first position can be obtained from the Queen's Gambit:
- 1. d4 d5
- 2. c4 e6
- 3. Nc3 Nf6
But this position can also be reached from the English Opening:
- 1. c4 e6
- 2. Nc3 Nf6
- 3. d4 d5
so the English Opening has transposed into the Queen's Gambit.
Script error: No such module "Chessboard". The second position shows another example. The position can arise from the French Defence:
- 1. e4 e6
- 2. d4 d5
- 3. exd5 exd5
- 4. Nf3 Nf6
The identical position can also be reached, with two extra moves played by each side, from the Petrov Defense:
- 1. e4 e5
- 2. Nf3 Nf6
- 3. Nxe5 d6
- 4. Nf3 Nxe4
- 5. d3 Nf6
- 6. d4 d5[3]
Script error: No such module "Chessboard". This third position shows another example. This position can be reached from the Exchange variation of the Queen's Gambit Declined:
- 1. d4 d5
- 2. c4 e6
- 3. Nc3 Nf6
- 4. cxd5 exd5
- 5. Bg5 Bb4
- 6. Qc2 h6
The identical position can also be reached from the Classical variation of the Nimzo-Indian Defence:
- 1. d4 Nf6
- 2. c4 e6
- 3. Nc3 Bb4
- 4. Qc2 d5
- 5. cxd5 exd5
- 6. Bg5 h6
Transposition possibilities of some openings
Some openings are noted for their wide range of possible transpositions, for example the Catalan Opening and Sicilian Defence.[2][4]
For a simple example, the opening moves 1.d4 e6 (the Horwitz Defence) can transpose very quickly into a wide range of openings, including: Template:Div flex row Script error: No such module "Chessboard". Script error: No such module "Chessboard". Script error: No such module "Chessboard".
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