Chikayasu KOSOKABE, a younger brother of Motochika and Nobuchika CHOSOKABE, a legitimate child of Motochika put their troops forward to capture Shozui-jo Castle after seizing Ichinomiya-jo Castle (Awa Province) and Ebisuyama-jo Castle.
そこで元親の弟、香宗我部親泰や元親の嫡男、長宗我部信親は一気に勝瑞城を攻め落とそうと兵を進め一宮城(阿波国)、夷山城を落とした。