Shaku

JapaneseTraditional unit (still used in some regions)

The Japanese foot, defined as exactly 10/33 meter (about 30.3 cm). Still the basis of carpentry and building dimensions in Japan.

1 shaku = 0.303030303 meters (approximately).

About the shaku

Shaku is the Japanese reading of the character for chi, the Chinese foot, which began as a hand span from thumb tip to fingertip. Japan adopted the Chinese measuring system around the year 701, and the shaku became its basic length, growing over the centuries to roughly a third of a meter.

Several versions coexisted. The ordinary carpenter's shaku, the kanejaku, was about 30.2 to 30.3 centimeters. A longer kujirajaku, used for cloth and said to have been marked on whale baleen, measured 125/330 meter, near 37.9 centimeters. A longer variant, the korai-shaku, was about 1.17 times the modern value, about 35.5 centimeters.

The Weights and Measures Act of 24 March 1891 ended the variation for the standard unit by defining it as exactly 10/33 meter, about 30.3 centimeters or 11.93 inches. Official use was banned in 1966, yet the shaku still sets building dimensions: a standard three shaku panel is rounded to 910 millimeters.

Sources: Wikipedia: Shaku (unit); Wikipedia: Japanese units of measurement; Japanese Wikipedia: Shakkanho (尺貫法)

Shaku conversion chart

1 shaku expressed in every other length unit:

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