Koku

JapaneseHistorical unit (no longer in standard use)

One hundred shō, about 180.39 L. The amount of rice thought to feed one person for a year; feudal domains were ranked by their koku.

1 koku = 180.3906837 liters (approximately).

About the koku

Rice decided rank in Tokugawa Japan, and the koku was the yardstick. A domain whose assessed income reached 10,000 koku could have a daimyo as its lord, and the Kaga domain, rated at about 1.025 million koku, was famous as the million-koku domain. The assessment was a notional yield, with other crops converted to their rice value, and real revenue averaged only around 40 percent of it.

One koku was commonly taken as enough rice to feed one person for a year, though a merchant house code cited in the sources allowed about 1.8 koku per man, so the rule of thumb is loose. The unit equals 10 to, 100 sho or 1,000 go, and it descends from the Chinese dan, which was about 59 litres under the Tang dynasty.

The Meiji law of 1891 fixed the sho from the old kyo-masu measuring box at 2401/1331 litre, which makes the koku about 180.39 litres, close to 5 bushels. Shipping and timber koku were different quantities. A lumber koku is about 278 litres, so the word always needs its context.

Sources: Wikipedia: Koku; Wikipedia: Kokudaka; Wikipedia: Japanese units of measurement

Koku conversion chart

1 koku expressed in every other volume unit:

More Japanese units

• gō (volume)
• shō (volume)
• tō (volume)
• sun (length)
• shaku (length)
• ken (length)
• jō (length)
• chō (length)
• ri (Japanese) (length)
• monme (weight & mass)
• kin (weight & mass)
• kan (weight & mass)
• jō (tatami mat) (area)
• tsubo (area)
• se (area)
• tan (area)

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