The Yin (Chinese: 引; pinyin: yǐn; Cantonese: jan) is a traditional Chinese unit of length. It is a well-established unit within the historical and modern Chinese systems of measurement.
Definition
The value of the yin has varied across different measurement standards:
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1915 Chinese measurement law: 1 yin = 100 chi (尺) = 32 meters (approximately 35.0 yards). Under this system, 1 yin equaled 1/15 of a li (里), or 10 zhang (丈).
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1929 Chinese measurement law (effective 1 January 1930): With the base unit chi redefined as exactly 1/3 meter, 1 yin = 100 chi = 33⅓ meters (approximately 36.45 yards). In this system, 1 yin = 1/15 of a li (市里, now 500 m).
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Engineering usage: In modern Chinese engineering contexts, the term yin (公引) is used as a metric-based unit equal to exactly 100 meters, analogous to a hectometre.
Relationship to Other Units
| Unit | Relative value | Notes |
|---|---|---|
| 1 li (市里) | 15 yin | Chinese mile |
| 1 yin | 10 zhang (市丈) | Chinese chain |
| 1 zhang | 10 chi (市尺) | Chinese yard |
| 1 chi | 10 cun (市寸) | Chinese foot |
Usage
The yin is a traditional Chinese unit that was historically used for land measurement and distance. Under the 1929 system, it was sometimes referred to as the "Chinese chain." In modern practice, the metric system (using meters and kilometres) is standard in China, but the traditional units, including the yin, remain defined in law and are occasionally referenced in historical contexts and certain specialized fields.
