Traditional Japanese units of measurement or the shakkanhō (尺貫法) 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 701. Following the 1868 Meiji Restoration, Imperial Japan adopted the metric system and defined the traditional units in metric terms on the basis of a prototype metre and kilogram. The present values of most Korean and Taiwanese units of measurement derive from these values as well.
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, and hammers manufactured in sun and bu sizes. Floorspace is expressed in terms of tatami mats, and land is sold on the basis of price in tsubo. Sake is sold in multiples of 1 gō, with the most common bottle sizes being 4 (720 mL) or 10 (1.8 L, isshōbin).
