Japanese units of measurement: Encyclopedia II - Japanese units of measurement - Length

Japanese units of measurement - Length

The basis of the shakkanhō length measurements is the shaku, which originated in ancient China. The other units are all fixed fractions or multiples of this basic unit. The shaku was originally the length from the thumb to the middle finger (about 18 cm, or 7 inches), but its length, and hence the length of the other units, gradually increased, since the length of the unit was related to the level of taxation.

Various different shaku developed for various purposes. The unit now most widely recognized as a shaku in Japan is the kanejaku (曲尺, kanejaku^?), shaku, the system shown in the table below. Kanejaku means "carpenter's square", and this shaku was the one used by Japanese carpenters. The carpenter's shaku, used for construction, preserved the original Chinese shaku measure, because it was never interfered with, whereas the other shaku systems, which were used for taxation or trade, were interfered with in order to increase taxation, and hence gradually varied from the original value.

The kujirajaku (鯨尺, kujirajaku^?), literally "whale shaku", was a standard used in the clothing industry. The name "whale shaku" comes from the measuring rulers used, which were made from whale whisker. A kujirajaku is 1 1/4 the length of a kanejaku.

As well as the kanejaku and kujirajaku system, various other shaku systems also exist, for example the gofukujaku (呉服尺), where gofuku means traditional Japanese clothes, such as kimonos. In the gofukujaku system, one shaku is equal to 1.2 times the kanejaku's shaku.

In 1891, the lengths of the two most common shaku were defined in terms of the metric system:

Shaku units are still used for construction materials in Japan. For example, plywood is usually manufactured in 182 cm × 91 cm (about 72 in × 36 in) sheets known in the trade as saburokuhan (３×６版, saburokuhan^?), or 3 × 6 shaku. Each sheet is about the size of one tatami mat. The thicknesses of the sheets, however, are usually measured in millimetres.

The names of these units also live on in the name of the bamboo flute shakuhachi (尺八, shakuhachi^?), literally "shaku eight", which is one shaku and eight sun in length, and the Japanese version of the Tom Thumb story, Issun Bōshi (一寸法師, Issun Bōshi^?), literally "one sun boy", as well as in many Japanese proverbs.

The Shōsōin in Nara has an ivory one-shaku ruler, the kōgebachiru-no-shaku (紅牙撥鏤尺, kōgebachiru-no-shaku^?).

The smallest units, mō, rin, and bu, are actually the names of fractions, 1/1,000, 1/100, and 1/10, respectively, which are also used as fractional units.

Adapted from the Wikipedia article "Length", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki