Koku Saitcho shounin.jpg

The is a Chinese-based Japanese unit of volume. 1 koku is equivalent to 10 or approximately , or about . It converts, in turn, to 100 shō and 1000 gō. One ''gō'' is the volume of the "rice cup", the plastic measuring cup that is supplied with commercial Japanese rice cookers.

The ''koku'' in Japan was typically used as a dry measure. The amount of rice production measured in ''koku'' was the metric by which the magnitude of a feudal domain (''han'') was evaluated. A feudal lord was only considered '' daimyō'' class when his domain amounted to at least 10,000 ''koku''. As a rule of thumb, one ''koku'' was considered a sufficient quantity of rice to feed one person for one year.

The Chinese equivalent or cognate unit for capacity is the ''shi'' or ''dan'' ( also known as ''hu'' (), now approximately 103 litres but historically about .

Chinese equivalent

The Chinese ''shi'' or ''dan'' is equal to 10 ''dou'' () " pecks", 100 ''sheng'' () " pints". While the current ''shi'' is 103 litres in volume, the ''shi'' of the Tang dynasty (618–907) period equalled 59.44 litres.

Modern unit

The exact modern is calculated to be 180.39 litres, 100 times the capacity of a modern . This modern is essentially defined to be the same as the from the Edo period (1600–1868), namely 100 times the equal to 64827 cubic in the traditional measuring system.

Origin of the modern unit

The , the semi-official one measuring box since the late 16th century under Daimyo Nobunaga, began to be made in a different (larger) size in the early Edo period, sometime during the 1620s. Its dimensions, given in the traditional Japanese length unit system, were 4 9 square times 2 7 depth. Its volume, which could be calculated by multiplication was:

1 = 100 = 100 × (49 × 49 × 27 ) = 100 × 64,827 cubic

Although this was referred to as or the "new" measuring cup in its early days, its use supplanted the old measure in most areas in Japan, until the only place still left using the old cup ("") was the city of Edo, and the Edo government passed an edict declaring the the official nationwide measure standard in 1669 ( Kanbun 9).

Modern measurement enactment

When the 1891 Japanese was promulgated, it defined the unit as the capacity of the standard of 64827 cubic . The same act also defined the length as metre. The metric equivalent of the modern is litres. The modern is therefore litres, or 180.39 litres.

The modern defined here is set to equal the so-called ( or "compromise "), measuring 302.97 mm, a middle-ground value between two different standards. A researcher has pointed out that the () cups ought to have used which were 0.2% longer. However, the actual measuring cups in use did not quite attain the metric, and when the Japanese Ministry of Finance had collected actual samples of from the (measuring-cup guilds) of both eastern and western Japan, they found that the measurements were close to the average of and .: "The results of measuring original vessels at both the East and West yielded (a value) near the average of and () ".

Lumber koku

The "lumber " or "maritime " is defined as equal to 10 cubic in the lumber or shipping industry, compared with the standard measures 6.48 cubic . A lumber is conventionally accepted as equivalent to 120 board feet, but in practice may convert to less. In metric measures 1 lumber is about .

Historic use

The exact measure now in use was devised around the 1620s, but not officially adopted for all of Japan until the Kanbun era (1660s).

Feudal Japan

Under the Tokugawa shogunate (1603–1868) of the Edo period of Japanese history, each feudal domain had an assessment of its potential income known as ''kokudaka'' (production yield) which in part determined its order of precedence at the Shogunal court. The smallest ''kokudaka'' to qualify the fief-holder for the title of '' daimyō'' was 10,000 ''koku'' (worth ) and Kaga han, the largest fief (other than that of the '' shōgun''), was called the "million-''koku'' domain". Its holdings totaled around 1,025,000 ''koku'' (worth ). Many samurai, including '' hatamoto'' (a high-ranking samurai), received stipends in ''koku'', while a few received salaries instead.

The ''kokudaka'' was reported in terms of brown rice (''genmai'') in most places, with the exception of the land ruled by the Satsuma clan which reported in terms of unhusked or non-winnowed rice (. Since this practice had persisted, past Japanese rice production statistics need to be adjusted for comparison with other countries that report production by milled or polished rice.

Even in certain parts of the Tōhoku region or Ezo (Hokkaidō), where rice could not be grown, the economy was still measured in terms of ''koku'', with other crops and produce converted to their equivalent value in terms of rice. The ''kokudaka'' was not adjusted from year to year, and thus some fiefs had larger economies than their nominal ''koku'' indicated, due to land reclamation and new rice field development, which allowed them to fund development projects.

As measure of cargo ship class

''Koku'' was also used to measure how much a ship could carry when all its loads were rice. Smaller ships carried 50 ''koku'' () while the biggest ships carried over 1,000 ''koku'' (). The biggest ships were larger than military vessels owned by the shogunate.

In popular culture

The Hyakumangoku Matsuri (Million-''Koku'' Festival) in Kanazawa, Japan celebrates the arrival of ''daimyō'' Maeda Toshiie into the city in 1583, although Maeda's income was not raised to over a million ''koku'' until after the Battle of Sekigahara in 1600.

In fiction

The James Clavell novel Shōgun uses the Koku measure extensively as a plot device by many of the main characters as a method of reward, punishment and enticement. While fiction, it shows the importance of the fief, the rice measure and payments.

Explanatory notes

References

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{{Means of Exchange

Economy of feudal Japan
Human-based units of measurement
Japanese historical terms
Obsolete units of measurement
Units of volume
Standards of Japan