On February 1, 1582, Yoshimasa, who was displeased with Katsuyori's policy to effectuate another increase in forced labor for the construction of Shinpu-jo Castle, finally betrayed Katsuyori and defected to the Oda clan by sending his younger brother, Yoshitoyo UEMATSU, to Nobutada ODA (Nobunaga's eldest son) as a hostage.
天正10年（1582年）2月1日、新府城築城のため更に賦役が増大していたことに不満を募らせた義昌はついに勝頼を裏切り、織田信忠（信長の長男）に弟の上松義豊を人質として差し出し、織田氏に寝返った。