There is a theory arguing that although the code advocates direct line succession, it was not created with the purpose of denying the principle of brother to brother succession, but permitting the princes whose mother was not from the imperial family to take the throne.
直系継承を主張しながらも、兄弟継承原理を否定しようとして作られたのではなく、皇族以外の母を持つ皇子を即位させるために作られたのだとする説もある。