There is an influential theory that he was the same person as KIYOHARA no Sadahira, on whom historical materials indicate that he was Jugoinoge (Junior Fifth Rank, Lower Grade) and the Chinju-fu shogun (Commander-in-Chief of the Defense of the North) and actively engaged in the Battle of Enkyu against the Ezo (Japanese northerners) and other battles which occurred in the Enkyu era (1069-1074).
延久年間に行われた延久蝦夷合戦などで活躍し鎮守府将軍従五位下であったとの史料がある清原貞衡と同一人物であるとの有力説がある。