Having a sexual intercourse with a woman and then with her mother (the four charges described above are summarized as 'Oyakotawake' in the section of Emperor Chuai in "Kojiki," thus there is a theory stating that these are divided only for the sake of rhetoric and thus have no difference in the meaning).
-ある女と性交し、その後その母と相姦すること（以上4罪は『古事記』仲哀天皇段に「上通下通婚（おやこたわけ）」として総括されており、修辞技法として分化されているだけで、意味上の相違はないとの説もある）