In 1521, the force of the Imagawa clan lead by Masashige KUSHIMA, the lord of Hijikata-jo Castle which was governed by the Imagawa clan of Suruga Province, invaded in the western county alongside of the Fuji-gawa River and approached near Kofu, Nobutora backed off to the Yogaiyama-jo Castle in the north east of his residence in Kofu, and defeated the Imagawa at the Battle of Iidakawara (Iida-cho, Kofu City) and the Battle of Kamijokawara (Kai City, former Shikishima-machi, Nakakoma County).
大永元年（1521年）には駿河の今川氏配下の土方城主福島正成を主体とする今川勢が富士川沿いに西郡まで侵攻し甲府へ迫ると、甲府館北東の要害山城へ退き、今川勢を飯田河原合戦（甲府市飯田町）、上条河原合戦（甲斐市、旧中巨摩郡敷島町）で撃退する。