It is considered that, in Japan, kubunden was introduced as it was in Tang, because the system in Tang was used as a reference in establishing the ryo (or ritsuryo) code in the Asuka period.
日本では、飛鳥時代に令（または律令）を制定する際、唐の制度を参考としたため、唐と同様に口分田が導入されたと考えられる。