The Imperial Court decided local administration sections in order to establish centralized administrative framework and divided various provinces into four grades in accordance with political power, economic power and national power such as land area, kokudaka (crop yield), population.
朝廷は中央集権体制を確立するために地方行政区画をおこない、政治力・経済力や土地面積・石高・人口などの国力により地方諸国を四等級に分けた。