According to "Azuma Kagami," Kagetoki begged Yoshimori that he wanted to be a Betto for a day and Yoshimori allowed this because he was not busy with his job at the time, but this was a conspiracy plan and Kagetoki took this opportunity to take over the position.
『吾妻鏡』はこの交代について、景時が一日だけでも仮に別当になりたいと懇願し、義盛がそれならばと暇のついでにこれを許したが、景時が奸計をもって別当職を奪ってしまったとしている。