Feudal organization in Japan was, in part, conducted by land surveys classifying domains by their productive output in rice, specifically koku, called the kokudaka. The kokudaka was a holdings production, rather than it's collected tax and determined the level of taxation for the land and it's influence in shogunate courts. A daimyo was a feudal lord whose estate produced in excess of 10,000 koku and served as the highest order of classification, with 250-300 in Japan at a given time. An important note when talking about koku is that the unit itself is not a direct representation of actual rice yield, but rather the assessed economic value of a holdings production, and may include other crops or industry.

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You can find more context for the koku and feudal Japanese economics in Phillip Curtin's book referenced below, where the above information is sourced from.

Curtin, P. D. (2009). Meiji Japan: Revolutionary Modernization. In The world and the west: The European Challenge and the overseas response in the age of Empire (pp. 158–159). Cambridge University Press.