He was the son and heir of Chōsokabe Kunichika and his mother was a daughter of the Saitō clan of Mino Province. He is said to have been born in Okō Castle in the Nagaoka district of Tosa. Motochika was a quiet youth and his father was said to have fretted about the boy's gentle nature ; Kunichika's worries evaporated when Motochika later proved himself a skilled and brave warrior. When Motochika came of age, his father had already begun to draw away from the Ichijô, and Motochika would carry on his work.
Unifying Shikoku
In the 1562 at Battle of Asakura, Chosokabe Motochika defeated Motoyama Shigetoki and by forming alliances with local families, Motochika was able to build his power base on the Kōchi plain. in the 1569, while being careful to remain ostensibly loyal to the Ichijô over the next few years, Motochika's power grew to the extent that he was strong enough to march on the rival Aki clan of east Tosa with 7,000 men, then went on to take Aki Castle. In the course of the decade he was awarded a court rank and was sufficiently confident after the reduction of the Aki to finally turn on the Ichijô. In 1573, While still lord of the Hata district of Tosa, Ichijō Kanesada was unpopular and had already suffered the defection of a number of important retainers. Seizing the opportunity, Motochika wasted no time in marching on the Ichijô's headquarters at Nakamura and Kanesada fled to Bungo, defeated. In 1575, at the Battle of Shimantogawa, he defeated the Ichijo family. Later in 1575, Motochika was victorious at the Battle of Watarigawa, gaining control of Tosa Province. Following his conquest of Tosa, Motochika turned north and prepared for an invasion of Iyo. The lord of that province was Kôno Michinao, a daimyo who had once been driven from his domain by the Utsunomiya clan, returning only with the assistance of the powerful Môri. It was unlikely that Kôno could count on that sort of help again, however-presently the Môri were embroiled in a war with Oda Nobunaga. Nonetheless, Chosokabe's campaign in Iyo did not go off without a hitch. In 1579, 7,000-man Chosokabe army, commanded by Kumu Yorinobu, met the forces of Doi Kiyonaga at the Battle of Mimaomote. In the ensuing battle, Kumu was killed and his army defeated, though the loss proved little more than an unfortunate delay. The next year, Motochika led some 30,000 men into Iyo, and forced Kôno to flee to Bungo province. With little interference from either the Môri or the Ôtomo, Chosokabe was free to press onwards, and in 1582, he stepped up ongoing raids into Awa and defeated Miyoshi clan, led by Sogō Masayasu at the Battle of Nakatomigawa. By 1583, Chosokabe troops had subdued both Awa and Sanuki, Over the ensuing decade, he extended his power to all of Shikoku, making Motochika's dream of ruling all of Shikoku a reality. This included with the Battle of Hiketa in 1583.
Motochika died in 1599 at age 60 at his mansion in Fushimi. His successor was Chōsokabe Morichika. In addition to his leadership, Motochika is remembered for his '100-Article Code of the Chosokabe' and his struggle to found an economically strong castle town, moving in the course of his career from Oko to Otazaka and on to Urado.
He is a playable character in Pokémon Conquest, with his partner Pokémon being Dewott and Samurott. Motochika is a playable character from Samurai Warriors 2 Xtreme Legends onwards, where he wields a shamisen, he continuously calls himself as "The Bat King", due to Nobunaga historically referring to him as a "the bat who refuses to fly away from its home". Motochika is also a playable character in the Sony PlayStation game, Sengoku Basara where he wields an anchor and appears as a pirate. He also appears in the anime adaptation of the game.
