According to Hashimoto, Kiyomori seized the chance by making Moriko (who was the widow of the former Regent) the foster mother of the prince that Shigeko gave birth to, and therefore Kiyomori became the 'father of the foster mother of the Crown Prince' and used this as a reason to promote him to Nai-daijin and Daijyo-daijin (Hashimoto 200622-24).
橋本によれば、清盛はこの状況を奇貨として滋子の生んだ皇子の養母を「先の摂政の未亡人」である盛子に引き受けさせ、「東宮の養母の父親」である清盛が内大臣や太政大臣に出世する口実としたとされる（橋本200622-24）。