(There is another theory that Prince Naka no Oe could not succeed to the throne fifteen years after Isshi-no-hen (a Murder in the Year of Isshi), since he had an affair with his real younger sister, Princess Hashihito, or as opposed to this, it was said Princess Hashihito (Nakatsusumera-mikoto) was enthroned as a temporal Emperor. There are various theories concerning the reason why Prince Naka no Oe was finally enthroned in his later years.)
（一説に、中大兄皇子が同母妹の間人皇女と不倫関係を持っていた為に乙巳の変から15年以上経過してもなお即位できなかったとの説や、反対に間人皇女（＝中皇命）は中継ぎの大王として即位していたとの説もある。中大兄皇子が（結果的に）晩年にやっと即位した理由については他にも様々な説がある。）