The shaku (尺) is an archaic unit of length in Japan, approximately equal to the foot. Since 1891, the shaku has been defined to equal 10/33 meters (approximately 30.3 cm, or 11.93 inches), or 3.3 shaku to the meter. A single shaku is divided into 10 sun.

Another unit of length also called the shaku was used only for measuring cloth. This shaku measured 125/330 meters (approximately 37.9 cm, or 14.9 inches). When a distinction needed to be made between the two shaku, the cloth unit was referred to as kujirajaku (whale shaku, as the rulers for measuring cloth were made from whale whisker) and the other shaku was referred to as kanejaku (metal shaku).

While Japanese law required official use of these units be discontinued on March 31, 1966, the shaku is still used in some fields in Japan, such as traditional carpentry. The ken and jō are larger than a shaku: six shaku make up one ken; ten shaku make up one jō. The ken is commonly the distance between pillars in traditional buildings such as Buddhist temples and Shinto shrines.

The shakuhachi is a Japanese musical instrument nominally measuring 1 shaku and eight (hachi) sun in length.

External links

• Japanese Metric Changeover by Joseph B. Reid, President Emeritus, Canadian Metric Association (U.S. Metric Association page)
• Details of the two shaku units at sizes.com