By the way there were some Emperors that existed who were not able to officially become Emperors since they did not go through the successive ceremony in the past. (For example, Emperors of Northern Court during the spilt of the political power of the period of the Northern and Southern Courts)
なお、過去に継承の儀を執り行うことが出来なかったため、正統な皇位継承者にはなりえなかった天皇が存在する（南北朝時代分裂期の北朝の天皇など）。