After World War II, a theory known as the dynastic state theory was developed, and according to this theory, the political system of the regime that held power in the tenth and eleventh centuries was different from that of the Ritsuryo regime (a political system based on the philosophies of Confucianism and Chinese Legalism).
なお、戦後において10-11世紀の国家体制を律令国家体制とは異なる体制（王朝国家体制）とする王朝国家論が唱えられるようになった。