Koku (traditional unit of volume)

Koku (石) is a traditional unit of measurement used mainly to express production volumes of sake and rice. One koku is equivalent to 180 liters, which the source describes as enough to produce about 1,500 go (合) of sake. At sake breweries in particular, the koku is widely used to express the amount of rice used in brewing and the volume of finished sake in storage, making it an important indicator of a brewery's production scale. The koku is thus an indispensable unit in the production and distribution of sake.