Tei MORITA, one of the supporters of the imperial succession code theory, argues that Fukai-no-Joten/ Fukaijoten includes plural contents and one of them is the law related to the imperial succession, and he also supposed that the code contains another law related to the Imperial Throne.
皇位継承法論者でも、森田悌は、不改常典は複数の内容を持ち、一部に皇位継承に関する法、他に皇位に関する法があったとする説もある。