Motochika Chosokabe was the son of Kunichika Chosokabe, a vassal of the Ichijo clan of Tosa Province. In 1545, his father was killed fighting Fusamoto Ichijo, but his forces won the battle. Motochika was thus an orphan, and the clan was taken care of by his mother Naomi Chosokabe, and later, his brother-in-law Sanefusa Chosokabe. When Sanefusa died in 15, Motochika became the daimyo. He reconquered Shikoku, defeating the Kono, Sogo, and Miyoshi clans to unite the island once more, as the clans had gained independence following Sanefusa's death. Motochika became allies with the Akechi clan of Mino Province, who were vassals of the Oda. In 1577, he fought in the Battle of Tetorigawa against the Uesugi alongside Mitsuhide Akechi, and fought again at the Second Battle of Kizugawa two years later. In 1582, Nobunaga Oda, the lord of the Oda clan, invaded Shikoku, betraying Mitsuhide, who, along with Motochika, betrayed him in turn at Honnoji. They struck down Nobunaga and Mitsuhide became Shogun, but in 1582, Motochika and Mitsuhide were defeated at the Battle of Yamazaki, with Mitsuhide being killed and Motochika wounded. Motochika paid homage to Nobunaga's successor Hideyoshi Hashiba, who forced the warlords to surrender one-by-one. Motochika rose up in rebellion against the Toyotomi clan in 1598 after Hideyoshi died, as did all of the other warlords. Motochika resisted the Tokugawa clan, the new shoguns and the most powerful clan, by joining Mitsunari Ishida's Western Army, a collection of Toyotomi loyalists who wanted to defeat the Tokugawa, who were over-powerful by now. Motochika was wounded in the Battle of Kuzegawa in 1600, and died of illness shortly after. He was succeeded by his son Morichika Chosokabe.