View source for Cun (unit)

{{Short description|Chinese unit of length}}
{{More citations needed|date=September 2009}}
{{Infobox transliteration
| title = Cun
| c = {{linktext|寸}}
| p = cùn |mi={{IPAc-cmn|c|un|4}}
| w = ts'un<sup>4</sup>
| kanji = 寸
| kana = すん
| revhep = sun
| hangul = 치
| hanja = <small>n/a</small>
| rr = chi
| mr = ch'i
| hangul2 = 촌
| hanja2 = 寸
| rr2 = chon
| mr2 = ch'on
| vie = thốn
| ibox-order = zh, ja, ko1, ko4, ko3, vi}}
{{Infobox unit
| name     = Cun
| standard = [[Chinese units of measurement|Chinese unit]]
| quantity = [[length]]
| image    = [[File:Wooden Ruler.jpg|250px]]
| caption  = Wooden ruler of the western Han dynasty, unearthed at Jinguan Pass Site in Jinta County
| units1   = [[metric system|metric]] ([[SI]])  units
| inunits1 = {{sfrac|30}}&nbsp;m<br /><!--
    --> ~33.33&nbsp;[[millimetre|mm]]
| units2   = [[imperial units|imperial]]/[[US customary units|US]]&nbsp;units
| inunits2 = ~{{convert|1/30|m|in|disp=out|lk=on|comma=gaps|sigfig=5}}
}}
{{Infobox unit
| name          = Tsun
| standard      = Chinese unit
| quantity      = length
| image         = [[File:Hong Kong ruler close-up 002.jpg|250px]]
| caption       = A section of an old Hong Kong ruler, showing the last (10th) ''cun'' of a ''chi''. One can see that the ''chi'' in that jurisdiction was exactly equal to {{sfrac|14|5|8}} of an inch. A metric ruler is shown next to it for comparison.
| units1        = metric (SI)  units
| inunits1      = 37.1475&nbsp;mm
| units2        = imperial/US&nbsp;units
| inunits2      = {{sfrac|1|37|80}}&nbsp;in
}}
{{Infobox unit
| name     = Sun
| standard = [[Japanese units of measurement|Japanese unit]]
| quantity = length
| units1   = metric (SI) units
| inunits1 = {{frac|1|33}}&nbsp;m<br /><!--
    --> ~30.30&nbsp;mm
| units2   = imperial/US&nbsp;units
| inunits2 = ~{{convert|1/33|m|in|disp=out|comma=gaps|sigfig=5}}
}}

A '''''cun''''' ({{zh|c=寸}} {{respell|ts'wun}}; [[Pinyin]] cùn [[International Phonetic Alphabet|IPA]] |mi={{IPAc-cmn|c|un|4}}), often glossed as the ''Chinese inch'', is a traditional [[Chinese units of measurement|Chinese unit of length]]. Its traditional measure is the width of a person's thumb at the knuckle, whereas the width of the two forefingers denotes 1.5&nbsp;cun and the width of four fingers (except the thumb) side-by-side is 3 cuns.<ref>{{Cite web|url=http://www.tcmstudent.com/study_tools/Cun%20Measurements.html|title=TCM Student: Cun Measurements|website=www.tcmstudent.com|access-date=2018-02-10}}</ref> It continues to be used to chart [[acupuncture point]]s on the human body, and, in various uses for [[traditional Chinese medicine]].

The cun was part of a larger decimal system. A cun was made up of 10 [[fen (length)|fen]], which depending on the period approximated lengths or widths of millet grains,<ref>{{Cite web |last=Chu |first=Feng-chieh |editor-last=Binkley |editor-first=Jim |title=Yu-Ku-Chai: Vol 2, Chapter 3: Deliberations over Accurate Measurements |url=https://web.cecs.pdx.edu/~jrb/chin/v23/v23.htm |access-date=2022-03-10 |website=web.cecs.pdx.edu |at=https://web.cecs.pdx.edu/~jrb/chin/}}</ref> and represented one-tenth of a [[chi (unit)|chi]] ("Chinese foot").<ref>{{Cite journal |last=Keightley |first=David N. |date=1995 |title=A Measure of Man in Early China: In Search of the Neolithic Inch |url=https://www.jstor.org/stable/43290484 |journal=Chinese Science |issue=12 |pages=18–40 |jstor=43290484 |issn=0361-9001}}</ref> In time the lengths were standardized, although to different values in different jurisdictions. (See ''[[Chi (unit)]]'' for details.)

In Hong Kong, using the traditional standard, it measures ~3.715&nbsp;cm (~1.463&nbsp;in) and is written "tsun".<ref>[https://www.elegislation.gov.hk/hk/cap68 Cap. 68 WEIGHTS AND MEASURES ORDINANCE]</ref> In the twentieth century in the [[Republic of China (1912–1949)|Republic of China]], the lengths were standardized to fit with the metric system, and in current usage in [[People's Republic of China]] and [[Taiwan]]{{Citation needed|date=September 2009}} it measures {{sfrac|3|1|3}}&nbsp;cm (~1.312&nbsp;in).

In Japan, the corresponding unit, {{nihongo|[[Japanese units of measurement#Length|''sun'']]|寸}}, was standardized at {{frac|1000|33}}&nbsp;mm (3.{{overline|03}}&nbsp;cm, ~1.193&nbsp;in, or ~0.09942&nbsp;ft).
{{clear}}

== See also ==
* ''[[Shaku (unit)|shaku]]''

== References ==
{{reflist}}

== External links ==
{{Wiktionary|寸|tsun}}
{{Commonscat}}
* [http://www.tcmstudent.com/study_tools/Cun%20Measurements.html Cun measurements]

{{Japanese architectural elements}}

{{DEFAULTSORT:Cun (Length)}}
[[Category:Units of length]]
[[Category:Human-based units of measurement]]