Sun

JapaneseTraditional unit (still used in some regions)

One tenth of a shaku, about 3.03 cm. The Japanese 'inch', still used in carpentry.

1 sun = 0.0303030303 meters (approximately).

About the sun

Sun is the Japanese reading of the Chinese character for cun, the Chinese inch, which was traditionally the width of a person's thumb at the knuckle. Japan took the whole system over from China, and the sun kept its place as one tenth of the foot-like shaku.

Because the shaku was fixed in 1891 at 10/33 meter, the sun works out to 1/33 meter, about 30.3 millimeters or 1.19 inches. That makes it about 19 percent longer than a modern inch. Before the legal definition, the size drifted slightly between eras and regions, so older measurements in sun carry some uncertainty.

Smaller steps below it, such as the bu, divide it further. Today the sun survives mainly in carpentry, joinery and traditional crafts, where dimensions are still quoted in shaku and sun before being translated into the millimeters on modern rulers.

Sources: Wikipedia: Cun (unit); Wikipedia: Shaku (unit); Wikipedia: Japanese units of measurement

Sun conversion chart

1 sun expressed in every other length unit:

More Japanese units

• shaku (length)
• ken (length)
• jō (length)
• chō (length)
• ri (Japanese) (length)
• monme (weight & mass)
• kin (weight & mass)
• kan (weight & mass)
• gō (volume)
• shō (volume)
• tō (volume)
• koku (volume)
• jō (tatami mat) (area)
• tsubo (area)
• se (area)
• tan (area)

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