The reasons why the story was handed down as the Yoshitsune's exploit include that a historical material was found in Kyoto in which Yoshitsune himself described the progress of the Battle of Ichinotani as a supreme commander of backdoor troops after the battle, and that Yukitsuna was later banished and ruined.
後世義経の軍功として伝えられることとなった原因としては、戦後に京で義経自身が搦手軍の総大将として一ノ谷合戦の経過を語っていることや、行綱のその後の追放・没落などが挙げられている。