Chosokabe Motochika advanced into Iyo Province during the 1580s and briefly controlled Ozu Castle. However, in 1585, Toyotomi Hideyoshi launched his conquest of Shikoku. Kobayakawa Takakage led Mori forces ashore in Iyo, driving out the Chosokabe forces. Motochika was confined to Tosa alone and Ozu Castle passed to the Mori (Kobayakawa) clan. As evidence of the Chosokabe's brief rule over Iyo, Ozu Castle stands as one of the sites where Motochika's dream of unifying Shikoku came to an end.