Koku

The koku (斛) is a Chinese-based Japanese unit of volume. One koku is equivalent to 10 to (斗) or approximately 180 litres (40 imp gal; 48 US gal), or 150 kilograms (330 lb) of rice. It converts, in turn, to 100 shō and 1,000 gō. One gō is the traditional volume of a single serving of rice (before cooking), used to this day for 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 (Chinese: 石; pinyin: shí, dàn; Wade–Giles: shih, tan) also known as hu (斛; hú; hu), now approximately 103 litres but historically about 59.44 litres (13.07 imp gal; 15.70 US gal).