But through a law introduced by Prince Shotoku (the Seventeen Article Constitution of the Asuka Period) and government organizational reform (the system of twelve courtly ranks), after the Taika Reform of 645 the political system shifted to an emperor-centered system.
しかし、聖徳太子の法律(十七条憲法)・官制改革(冠位十二階)を経て、大化の改新（645年）後、天皇中心の政治へ変換していった。