Japanese units

Traditional Japanese units of measurement or the shakkanhō (, "foot–string system") is the traditional system of measurement used by the people of the Japanese archipelago. It is largely based on the Chinese system, which spread to Japan and the rest of the Sinosphere in antiquity. It has remained mostly unaltered since the adoption of the measures of the Tang Dynasty in AD 701. Following the Meiji Restoration, Imperial Japan adopted the metric system and defined the traditional units in metric terms on the basis of a prototype meter and kilogram. The present values of most Korean and Taiwanese units of measurement derive from these values as well, owing to their long occupations by the Japanese.

For a time in the early 20th century, the traditional, metric, and English systems were all legal in Japan. Although commerce has since been legally restricted to using the metric system, the old system is still used in some instances. The old measures are common in carpentry and agriculture, with tools such as chisels, spatels, saws, hammers manufactured in sun and bu sizes. Floorspace is reckoned in terms of tatami mats and land is sold on the basis of price in tsubo. Many rice cookers are sold with measuring cups of 1 gō.

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