Shaku (unit)

 or Japanese foot is a Japanese unit of length derived (but varying) from the Chinese , originally based upon the distance measured by a human hand from the tip of the thumb to the tip of the forefinger (compare span). Traditionally, the length varied by location or use, but it is now standardized as .
Etymology in English.
 entered English in the early 18th century, a romanization of the Japanese Go-on reading of the character for .
Use in Japan.
The had been standardized as since 1891. This means that there are 3.3 () to one meter.
The use of the unit for official purposes in Japan was banned on March 31 1966, although it is still used in traditional Japanese carpentry and some other fields, such as kimono construction. The traditional Japanese bamboo flute known as the ( and ) derives its name from its length of one and eight . Similarly, the remains in use in the Japanese lumber trade.
In Japanese media parlance, refers to screen time: the amount of time someone or something is shown on screen (similar to the English "footage").
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 (also known as the ) was 1.17 times longer than the present value (). 
Carpenter's unit and tailor's unit.
Another variant was used for measuring cloth, which measured meters (), and was known as the , as baleen (whale whiskers) were used as cloth rulers.
To distinguish the two variants of , the general unit was known as the . The Shōsōin in Nara preserves some antique ivory one- rulers, known as the .
Derived units.
Length.
Just as with the Chinese unit, the is divided into ten smaller units, known as in Japanese, and ten together form a larger unit known in Japanese as a . The Japanese also had a third derived unit, the , equal to six ; this was used extensively in traditional Japanese architecture as the distance between supporting pillars in Buddhist temples and Shinto shrines.
Volume.
Ten cubic comprised a , reckoned as the amount of rice necessary to sustain a peasant for a year.
Outside Japan.
The Japanese also forms the basis of the modern Taiwanese foot.
In 1902, the Korean Empire adopted the Japanese definition of the as that of the (). 