In 1535, he started attacking Imagawa and a battle occurred at the border of Manzawa (Tomizawa-cho, Minamikoma County), the Hojo clan who had a matrimonial relation with the Imagawa clan invaded Yamanaka (Yamanakako-mura, Minamitsuru County) via Kagosaka-toge Pass and defeated the Oyamada clan and the Katsunuma clan.
天文(元号)4年（1535年）には今川攻めを行い、国境の万沢（南巨摩郡富沢町）で合戦が行われると、今川と姻戚関係のある北条氏が籠坂峠を越え山中（南都留郡山中湖村）へ侵攻され、小山田氏や勝沼氏が敗北している。