{{Short description|Chinese unit of length}} {{More citations needed|date=September 2009}} {{Infobox Chinese | 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 | 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 unit | quantity = length | image = 250px | caption = Wooden ruler of the western Han dynasty, unearthed at Jinguan Pass Site in Jinta County | units1 = metric (SI) units | inunits1 = {{sfrac|30}} m<br /><!-- --> ~33.33 mm | units2 = imperial/US 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 = 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 mm | units2 = imperial/US units | inunits2 = {{sfrac|1|37|80}} in }} {{Infobox unit | name = Sun | standard = Japanese unit | quantity = length | units1 = metric (SI) units | inunits1 = {{frac|1|33}} m<br /><!-- --> ~30.30 mm | units2 = imperial/US units | inunits2 = ~{{convert|1/33|m|in|disp=out|comma=gaps|sigfig=5}} }}
A '''''cun''''' ({{zh|c=寸}} {{respell|ts'wun}}; Pinyin cùn IPA |mi={{IPAc-cmn|c|un|4}}), often glossed as the ''Chinese inch'', is a traditional 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 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 points 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, 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 ("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 cm (~1.463 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, 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}} cm (~1.312 in).
In Japan, the corresponding unit, {{nihongo|''sun''|寸}}, was standardized at {{frac|1000|33}} mm (3.{{overline|03}} cm, ~1.193 in, or ~0.09942 ft). {{clear}}
== See also == * ''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 Category:Chinese units of measurement