Kokudaka is a term in Japanese feudalism that refers to a unit of land measurement and its corresponding economic value or income potential. Literally meaning "national value," kokudaka represents the estimated yield or annual income (in koku — a unit of rice measurement) that a particular parcel of land could generate in feudal Japan.
During the Edo period (1603-1868), the central government implemented a system known as sankin-kōtai or alternate attendance, requiring daimyōs, the regional feudal lords, to regularly attend the capital. As part of this system, the kokudaka was crucial in determining the rank and status of the daimyō. The higher the kokudaka of a lord's domain, the greater their prestige, authority, and social standing within the feudal hierarchy.
Kokudaka was assessed based on various factors, including the productivity and fertility of the land, its geographical location, natural resources, and the labor required for cultivation. The assessment was conducted by officials known as jashiu, who assessed the kokudaka periodically to reflect changes in the land's productivity.
The kokudaka had significant financial ramifications for the daimyōs as well. The income generated by their domains, based on the kokudaka, was used to maintain their households, pay salaries to retainers and samurai warriors, support their military forces, and participate in the mandatory sankin-kōtai system.
Overall, in the context of Japanese feudalism, the term kokudaka represents the economic and social value of a specific land holding within the hierarchical structure, determining the power and position of the daimyō within the feudal society.
