The "family" concept that appeared in Kizoku society reached the Emperor in the latter half of the eleventh century, starting the Insei political style in which the head of the Imperial family administered the affairs of the state as the retired emperor.
貴族社会に登場した「家」概念は、11世紀後半に天皇にまで及び、天皇家の家督者が上皇として政務に当たる院政の開始をもたらした。