Shaku (unit)


or Japanese foot is a Japanese unit of length derived from the Chinese chi, originally based upon the distance measured by a human hand from the tip of the thumb to the tip of the forefinger. Traditionally, the length varied by location or use, but it is now standardized as 10/33 meters.

Etymology in English

Shaku entered English in the early 18th century, a romanization of the Japanese Go-on reading of the character for.

Use in Japan

The shaku had been standardized as 10/33 meter since 1891. This means that there are 3.3 shaku to one meter. The use of the unit for official purposes was banned on March 31, 1966, although it is still used in traditional Japanese carpentry and some other fields. The traditional Japanese bamboo flute known as the shakuhachi derives its name from its length of one shaku and eight sun. Similarly, the koku remains in use in the Japanese lumber trade.
In Japanese media parlance, shaku refers to screen time, i.e. the amount of time someone or something is shown on screen.

History

Traditionally, the measurement varied over time, location, and use. By the early 19th century they were largely within the range of, but a longer value of the shaku was 1.17 times longer than the present value.

Carpenter's unit and tailor's unit

Another shaku variant used for measuring cloth, which was 125/330 meters. It was called the "whale shaku", because baleen were used as cloth rulers.
To distinguish the two variants of shaku, the general unit was known as the "metal shaku". The Shōsōin in Nara preserves some antique ivory one-shaku rulers, known as the kōgebachiru-no-shaku.

Derived units

Length

Just as with the Chinese unit, the shaku is divided into ten smaller units, known as in Japanese, and ten shaku together form a larger unit known in Japanese as a. The Japanese also had a third derived unit, the ken, equal to 6 shaku; this was used extensively in traditional Japanese architecture as the distance between supporting pillars in Buddhist temples and Shinto shrines.

Volume

Ten cubic shaku comprised a koku, reckoned as the amount of rice necessary to sustain a peasant for a year.

Outside Japan

This Japanese ex-official shaku also forms the basis of the modern Taiwanese foot.
In 1902, the Korean Empire adopted the Japanese definition of the shaku as that of the ja.