This was due to the background that Imperial Prince Koretaka's mother was from the Ki clan and did not have strong political support, on the other hand, Imperial Prince Korehito's mother was Yoshifusa's daughter, FUJIWARA no Meishi.
これは、惟喬親王の母が紀氏の出身で後ろ盾が弱く、一方惟仁親王の母が良房の娘藤原明子であったことによるものとされる。