Facing the highly volatile situation in East Asia in the seventh century, there emerged a need for "Wa" (ancient Japan, "Wa" was called "Japan" after the establishment of the name of the country by the Emperor Tenmu) to establish a centralized state under the Ritsuryo system.
このような７世紀の東アジアの激動を背景として，倭（天武天皇による国号制定以後日本）では中央集権的律令国家建設の必要性が生じた。