Once the Onin War started in 1467, Mototsuna took part in various battles in Kyoto together with the Kagawa clan as the head of an army from Sanuki Province.
応仁元年（1467年）に応仁の乱が起こると、元綱は香川氏とともに讃岐の軍勢を指揮し京都を転戦。