The cun ( chinese : 寸; pinyin: cùn; Wade : ts’un; Japanese  sun; Korean chon), often glossed as the Chinese inch, is a traditional    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 three cuns.^] In this sense it continues to be used to chart s on the human body in various uses of

The cun was part of a larger system, and represented one-tenth of a (“Chinese foot”). In time the lengths were standardized, although to different values in different jurisdictions. (See  for details.)

In Hong Kong, using the traditional standard, it measures ~3.715 cm (~1.463 in) and is written “tsun”.^[In the twentieth century in the , the lengths were standardized to fit with the metric system, and in current usage in  and  it measures ​3 ¹⁄₃ cm (~1.312 in).

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Cun Measurements of the Body

The system of using the cun is a genius way for acupuncture to measure and locate acupoints on anyone’s body. Since everyone’s body is of a different size and shape, using a person’s inborn measurement system makes finding the points a snap. The process starts with the measurement of one cun. This is done two ways: (a)using the width of the distal inter-phalangeal joint of the thumb (first finger) or (b)using the distance between the distal and proximal inter-phalangeal joints of the 3rd (middle) finger. All other specific measurements are outlined in the diagrams below. When in doubt in measuring, the thumb (1 cun) or the four finger method (3 cun) can always be used in a pinch.

  

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