That the Empress Shotoku (Retired Empress Koken) did not give up the right to appoint the heir to the Imperial Throne by firmly maintaining the position of being the direct descendant of the Emperor Tenmu since the era of the Emperor Junnin;
そもそも称徳天皇（孝謙上皇）は淳仁天皇時代から天武天皇系皇統の嫡流であるとする立場を堅持し続けて皇位継承者の選任権を手放さなかったこと。