Жапондық өлшемдер жүйесі: Шакканхо

Traditional system of measurement used in Japan

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 1gō, with the most common bottle sizes being 4 (720 mL) or 10 (1.8 L, isshōbin).

Customary Japanese units are a local adaption of the traditional Chinese system, which was adopted at a very early date. They were imposed and adjusted at various times by local and imperial statutes. The details of the system have varied over time and location in Japan's history. Japan signed the Treaty of the Metre in 1885, with its terms taking effect in 1886. with use of the other systems permitted as a transitional measure. Public education—at the time compulsory through primary school—began to teach the metric system. The Diet revisited the nation's measurements and, with the occupation's approval, promulgated a Measurements Law in June 1951 that reaffirmed its intention to continue Japan's metrication, effective on the first day of 1959. With the majority of the public now exposed to it since childhood, Redrafting of laws to use metric equivalents had already been accomplished, but conversion of the land registries required until 31 March 1966 to complete. Since the original fines for noncompliance were around $140 and governmental agencies mostly preferred to wait for voluntary conversion, metric use by December 1959 was estimated at only 85%. Since research showed that individual Japanese did not intend to actually use the metric units when given other options, however, sale and verification of devices marked with non metric units (such as rulers and tape measures noting shaku and sun) were criminalised after 1961. The "cloth" or 12,960shaku. A still longer unit was formerly standard in Ise on Honshu and throughout the 9 provinces of Kyushu, which comprised 50 chō, 3000 ken, A fourth and shorter ri of about 600m is still evident in some beach names. The "99 Ri" beach at Kujukuri is about 60 km. The "7 Ri" beach at Shichiri is 4.2 km long. + Table of LengthsUnitShaku 里 12,960  m 3.927km yd 2.440miNotes:
Exact figures follow the 1891 Law of Weights & Measures and 1959 International Yard and Pound Agreement. Approximations are rounded to four significant figures. The names of the smallest units, borrowed from Chinese, also function as the Japanese namesfor the fractions "hundredth", "thousandth", and "ten thousandth". The ken is the normal unit of distance and length; the hiro used as the equivalent unit of depth. Sometimes hiro is used equal to 5shaku (m, ~1.5152 metres). The traditional 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), 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 in the name of the bamboo flute shakuhachi (尺八), literally "shaku eight", which measures one shaku and eight sun, and the Japanese version of the Tom Thumb story, One inch boy (Issun Bōshi), literally "one sun boy", as well as in many Japanese proverbs.

Imperial units are sometimes used in Japan. Feet and inches are used for most non sport bicycles, whose tyre sizes follow a British system; for sizes of magnetic tape and many pieces of computer hardware; for photograph sizes; and for the sizes of electronic displays for electronic devices. Photographic prints, however, are usually rounded to the nearest millimetre and screens are not described in terms of inches but "type" (型, gata). For instance, a television whose screen has a 17 inch diagonal is described as a "17 type" (17型) and one with a 32 inch widescreen screen is called a "32 vista type" (32V型).