It is said that among the letters written by the successive chief priests and addressed to their successors, only Zonnyo's is defunct (even though Rennyo's biological son, Jitsugo, insisted that the letter did exist, but there was no conclusive evidence), and based on this, there is a theory that states that this was a form of coup d'etat by Senyu (Nyojo).
なお、歴代住職が後継者にあてた譲状が存如筆のものだけ現存しないとされる（蓮如実子の実悟は譲状は存在したと主張しているが確証はない）事から宣祐（如乗）による一種のクーデター説もある。