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The koku () is a Chinese-based Japanese unit of volume, equivalent to 10 to () or approximately 180 litres (40 imp gal; 48 US gal),[1] or about 5 bushels.[a] It converts, in turn, to 100 shō and 1000 .[2] One is the volume of the "rice cup", the plastic measuring cup that is supplied with commercial Japanese rice cookers.[3]

The koku in Japan was typically used as dry measure. The amount of rice production measured in koku was the metric by which the magnitude of a feudal domain (han) was evaluated.[4] A feudal lord was only considered daimyō class when his domain amounted to at least 10,000 koku.[4] As a rule of thumb, one koku was considered sufficient quantity of rice to feed one person for one year.[5][b][c]

The Chinese equivalent or cognate unit for capacity is the shi or dan (Chinese: ; pinyin: shí, dàn; Wade–Giles: shih, tan also known as hu (; ; hu), now approximately 103 liters but historically about 59.44 litres (13.07 imp gal; 15.70 US gal).

Chinese equivalentEdit

The Chinese shi or dan is equal to 10 dou (; dǒu; tou) "pecks", 100 sheng (; shēng; sheng) "pints".[9] While the current shi is 103 liters in volume,[10] the shi of the Tang Dynasty period equalled 59.44 liters.[9]

Modern unitEdit

The exact modern koku is calculated to be 180.39 liters, 100 times the capacity of a modern shō.[11][d] This modern koku is essentially defined to be the same as the koku from the Edo Period,[e] namely 100 times the shō equal to 64827 cubic bu in the traditional shakkanhō measuring system.[16]

Origin of the modern unitEdit

The ''kyō-masu京枡 "Kyoto masu", the semi-official one shō measuring box since the late 17th century under Nobunaga,[17] began to be made in a different (larger) size in the early Edo Period, sometime during the 1620's.[18] Its dimensions, given in the traditional Japanese shaku length unit system, were 4 sun 9 bu square times 2 sun 7 bu depth,[f][18][13] Its volume, which could be calculated by multiplication was:[11]

1 koku = 100 shō= 100 × (49 bu×49 bu×27 bu) = 100 × 64827 cubic bu[18]1[g]

Although this was referred to as shin kyō-masu or the "new" measuring cup in its early days,[18] its use supplanted the old measure in most areas in Japan, until the only place still left using the old cup ("edo-masu") Edo city,[19] and the Edo government passed an edict declaring the kyō-masu the official nationwide measure standard[17] in 1669 (Kanbun 9).[19]

Modern measurement enactmentEdit

When the 1891 Japanese Weights and Measures Act [ja] was promulgated, it defined the shō unit as the capacity of the standard kyo-masu of 64827 cubic bu.[15] The same act also defined the shaku length as 10/33 metre.[15] Thus the metric equivalent of the modern shō can calculated arithmetically,[h] and the result is 2401/1331000m3[20] The modern koku is therefore 2401/1331 litres,[i] or 1.8039 litres.[21]

The modern shaku defined here is set to equal the so-called setchū-shaku[j] or "compromise shaku".[22] A researcher has pointed out that (shin) kyō-masu [ja] cups ought to have used take shaku which were 0.2% longer.[12][k] However when the Japanese Ministry of Finance collected actual samples of masu from the masu-za [ja] (measuring-cup guilds) of both eastern and western Japan, they found that the measurements were close to the average of take shaku and kyoku-shaku.[25][l]

Lumber kokuEdit

The "lumber koku" or "maritime koku" is defined as equal to 10 cubic shaku in the lumber or shipping industry,[28] compared with the standard koku measures 6.48 cubic shaku.[6]. A lumber koku is conventionally accepted as equivalent to 120 board feet, but in practice may convert to less.[29] In metric measures 1 lumber koku is about 278.3 litres (61.2 imp gal; 73.5 US gal).

Historic useEdit

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

Feudal JapanEdit

Under the Tokugawa shogunate of the Edo period (1603–1868) of Japanese history, each feudal domain had an assessment of its potential income known as kokudaka 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 ¥705,528,600 in 2016[30]) and Kaga han, the largest (other than that of the shōgun), was called the "million-koku domain". Its holdings totaled around 1,025,000 koku (worth ¥72.3 billion in 2016). Many samurai, including hatamoto, received stipends in koku, while a few received salaries instead.

The production yield (koku-daka) was reported in terms of brown rice (genmai) in most places, with the exception of Satsuma clan which reported in terms of unhusked or non-winnowed rice (momi ()).[31] 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.[6]

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.[32] 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 classEdit

Koku was also used to measure how much a ship could carry when all its loads were rice. Smaller ships carried 50 koku (7.5 tonnes, 7.4 long tons, 8.3 short tons) while the biggest ships carried over 1,000 koku (150 tonnes, 150 long tons, 170 short tons). The biggest ships were larger than military vessels owned by the Shogunate.

In popular cultureEdit

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.

Explanatory notesEdit

  1. ^ 180 litres (4.9 imp bsh; 5.1 US bsh)
  2. ^ A koku of brown rice (unpolished rice) weighs about 150 kilograms (330 lb).[6][5] White rice (milled rice, polished rice) weighs about the same (150g per 1 gō).[7] But 1 koku of brown rice would only 0.91 koku of milled rice (white rice)[6] after processing (seimai精米), i.e., removing the rice bran).
  3. ^ Apparently 1.8 koku (1 koku and 8 to) was actually required for nourishment by a man each year, according to the conventional wisdom documented in a "home code" (kakun [ja]) of a certain merchant family in the Edo Period.[8]
  4. ^ Each shō was determined to measure 1803.9 cubic centimeters (millilitres)[12] or 1.803906 litres.[13].
  5. ^ The Edo Period koku was roughly 180 liters or 5 bushels.[14]
  6. ^ sun = 1/10 shaku and bu = 1/100 shaku respectively.
  7. ^ Also =100 × 64.827 cubic sun[13].
  8. ^ 64827 cubic bu = 64827/106 cubic shaku = 64827/106×(10/33)3 cubic metr. Divide both numerator and denominator by 27 yields 2401×103 / 1331×106.
  9. ^ A cubic meter equals 1000 litres
  10. ^ secchū may be the modern romanization.
  11. ^ One type of take shaku is the kyōho-shaku[23] which came into use in the Kyoho era (1716-173)[24] The average of the kyōho-shaku and the matashirō-shaku of the carpenter became the setchū-shaku.[22]
  12. ^ matashirō-shaku 又四郎尺 devised by a carpenter[22] is a type of the carpentry scale or kane-jaku,[26] aka kyoku-shaku 曲尺.[27]


  1. ^ Hayek, Matthias; Horiuchi, Annick, eds. (2014). Listen, Copy, Read: Popular Learning in Early Modern Japan. BRILL. p. 195, note 39. ISBN 9-00427-972-5.
  2. ^ a b Cardarelli, François (2003). " Old Japanese Units of Capacity". Encyclopaedia of Scientific Units, Weights and Measure. Translated by M.J. Shields. Springer Science & Business Media. p. 151. ISBN 1-85233-682-X.
  3. ^ Andoh, Elizabeth (2012). Washoku: Recipes from the Japanese Home Kitchen: A Cookbook. Ten Speed Press. p. 136. ISBN 0-307-81355-X.
  4. ^ a b Curtin, Philip D. (2002) [2000]. The World and the West: The European Challenge and the Overseas Response in the Age of Empire (revised ed.). Cambridge University Press. p. 159. ISBN 0-52189-054-3.
  5. ^ a b Francks, Penelope (2006). Rural Economic Development in Japan: From the Nineteenth Century to the Pacific War. Routledge. p. xvii. ISBN 1-134-20786-7.
  6. ^ a b c d Rose, Beth (2016) [1985]. Appendix to the Rice Economy of Asia. Routledge. p. 84. ISBN 1-31733-947-9.
  7. ^ Yamaguchi, Tomoko 山口智子 (2017). "Mushi kamado de taita beihan no bussei to oishisa no hyōka" 蒸しかまどで炊いた米飯の物性とおいしさの評価 [Evaluation of physical properties and taste of rice cooked by steamed rice cooker, Mushikamado] (PDF). Bulletin of the Faculty of Education. Natural Sciences. Niigata University. 34 (2): 224. Invalid |script-title=: missing prefix (help)
  8. ^ Ramseyer, Mark J. (1979). "Thrift and Diligence; Home Codes of Tokugawa Merchat Families". Monumenta Nipponica. Sophia University. 34 (2): 224.
  9. ^ a b Wittfogel, Karl A.; Fêng, Chia-Shêng (1946). "History of Chinese Society Liao (907-1125)". Transactions of the American Philosophical Society. Sophia University. 36: 609. JSTOR 1005570
  10. ^ Perdue, Peter C. (2005). China Marches West. Harvard University Press. p. 598. ISBN 0-674-01684-X.
  11. ^ a b By definition. 1 koku = 10 to = 100 shō.[2]
  12. ^ a b Midorikawa (2012), p. 99.
  13. ^ a b c Japanese government (1878). Le Japon à l'exposition universelle de 1878: 2ème partie (in French). Commission Impériale Japonaise. p. 18.
  14. ^ Wittfogel, Karl A. (1936). "Financial Difficulties of The Edo Bakufu". Harvard Journal of Asiatic Studies. Sophia University. 1 (3/4): 314, note 26. JSTOR 2717787
  15. ^ a b c Nihon shakai jii 日本社會事彙 (in Japanese). 2. Keizai Zasshi Sha. 1907. p. 1252. 升 六萬四千八百二十七立方分 Invalid |script-title=: missing prefix (help)
  16. ^ Weights and Measures Act (Japan) [ja] (1891).[15]
  17. ^ a b Yamamura, Kozo (1990), "8 The growth of commerce in medieval Japan", in Yamamura, Kozo (ed.), The Cambridge History of Japan, 3, p. 393
  18. ^ a b c d Amano (1979), p. 10–13.
  19. ^ a b Umemura, Mataji 梅村又次; Hayami, Akira 速水融; Miyamoto Matarō 宮本又郎, eds. (1979), Nihon keizaishi 1 keizaishakai no seiritsu: 17~18 seiki 日本経済史 1 経済社会の成立: 17~18世紀 (in Japanese), Iwanami Invalid |script-title=: missing prefix (help)
  20. ^ Koizumi, Kesakatsu 小泉袈裟勝, ed. (1981). Tan'i no jiten 単位の辞典 (in Japanese) (revised 4th ed.). Rateisu. p. 394. Invalid |script-title=: missing prefix (help)
  21. ^ Midorikawa (2012), p. 99: "1,803.9 cm3".
  22. ^ a b c Weights and Measures in Japan: Past and Present (1914), pp. 18–19: "The setchū-shaku.. [which] Inō Chūkei.. invented.. a mean between the matashirō-shaku and the kyōho-shaku, and was therefore called the measure of setchū (compromise). The length is the same as that of the present shaku".
  23. ^ JWMA 1978, p. 1.
  24. ^ Ōtsuki, Nyoden; Krieger, Carel Coenruad (1940). The Infiltration of European Civilization in Japan During the 18th Century. Brill. p. 598.
  25. ^ JWMA 1978, p. 2.
  26. ^ JWMA 1978, p. 25.
  27. ^ "kanejaku; kyokushaku" かねじゃく【曲尺】;きょくしゃく【曲尺】. Digital Daijisen デジタル大辞泉. Shogakukan. Retrieved 2019-08-03. Invalid |script-title=: missing prefix (help)
  28. ^ Totman, Conrad D. "The Green Archipelago: Forestry in Preindustrial Japan". University of California Press: 228, note 37. ISBN 0-52006-313-9. Cite journal requires |journal= (help)
  29. ^ United States Forest Service (1945), Japan: forest resources, forest products, forest policy, Division of forest economics, Forest service, U.S. Dept. of agriculture, p. 11
  30. ^ "Shōhisha bukka shisū (CPI) kekka" 消費者物価指数 (CPI) 結果 [Consumer Price Index (CPI) results] (CSV). Statistics Bureau of Japan (in Japanese). Ministry of Internal Affairs and Communications. Retrieved 14 April 2018. Invalid |script-title=: missing prefix (help)
  31. ^ Kurihara, Ryūichi (1972). Bakumatsu Nihon no gunsei 幕末日本の軍制 (in Japanese). Shin Jinbutsu Ōraisha. p. 195, note 39. Invalid |script-title=: missing prefix (help)
  32. ^ Beasley, William G. (1972). The Meiji Restoration. Stanford University Press. pp. 14–15. ISBN 0804708150.
  • Amano, Kiyoshi 天野 清 (1979), "Kyōmasu to Edomasu" 京枡と江戸枡, Keiryōshi kenkyū: journal of the Society of Historical Metrology, Japan (in Japanese), 1 (1): 10–19 Invalid |script-title=: missing prefix (help)