Kunihira who took part in the Battle of Oshu in 1189 was given a territory in Mutsu Province due to his distinguished service in such Battle, and he also departed for the front when the Rebellion of Kaneto Okawa broke out in 1190.
1189年（文治5年）の奥州合戦に従軍し戦功により陸奥国に所領を与えられ、1190年（文治6年）の大河兼任の乱に際しても出陣している。