In the early Heian period, job grades such as kurodo that had authority of comings and goings in the kokyu appeared, which lowered the role of the kokyu junishi, and in the middle of the tenth century, while the structural reform of the kokyu was performed in the form of the functions of eleven tsukasa being absorbed/integrated by the Naishino tsukasa, the Sekkanseiji Period (regency period) made a start.
平安時代に入ると、蔵人など後宮出入りの職権を持つ官職が登場するようになると、後宮十二司の役割が低下し、10世紀の中頃には内侍司に他の11司の機能が吸収・統合される形で後宮の機構改革が行われながら摂関政治期を迎えることになった。