The was a feudal domain under the Tokugawa shogunate of Edo period Japan, controlling all of Tosa Province in what is now Kōchi Prefecture on the island of Shikoku. It was centered around Kōchi Castle, and was ruled throughout its history by the tozama daimyō Yamauchi clan. Many people from the domain played important roles in events of the late Edo period including Nakahama Manjirō, Sakamoto Ryōma, Yui Mitsue, Gotō Shōjirō, Itagaki Taisuke, Nakae Chōmin, and Takechi Hanpeita. Tosa Domain was renamed during the early Meiji period until it was dissolved in the abolition of the han system in 1871 and became Kōchi Prefecture. History At the end of the Sengoku period, the Chōsokabe clan ruled Tosa Province. The Chōsokabe had briefly controlled the entire island of Shikoku under Chōsokabe Motochika from 1583 until he was defeated by Toyotomi Hideyoshi in the Invasion of Shikoku in 1585. Motochika fought for Hideyoshi in the Kyushu Campaign and the invasions of Korea. However, next daimyō Chōsokabe Morichika joined the pro-Toyotomi Western Army at the Battle of Sekigahara in 1600, and was subsequently deprived of his title, and later his life. The victorious Tokugawa shogunate ordered Yamauchi Kazutoyo, lord of Kakegawa Castle in Tōtōmi Province to take control of the province as daimyō of the newly-created Tosa Domain, with a nominal kokudaka of 202,600 koku. The Chōsokabe's former retainers were extremely hostile to the new regime, while Tosa peasants feared increased exploitation under the new lord and many fled across to the neighboring domains. Kazutoyo came in with only 158 mounted men, and had to petition the new government of the Tokugawa shogunate for help in pacifying his new domain. This was achieved by "ruse and violence ... Two boatloads containing 273 heads were sent to Tokugawa headquarters to demonstrate Yamauchi efficiency, and another 73 dissidents were crucified on the beach," however, stories that the Yamauchi invited major Chōsokabe retainers to a fake sumo tournament and had them massacred are believed to have been later fabrications. In any even, most of the old vassals of the Chōsokabe, who were half-peasants and half-soldiers, were allowed to remain as lower-ranked samurai within the new regime, with retainers of the Yamauchi clan monopolizing the senior position, and with the most senior Yamauchi retainers and clan members assisted to key points within the domain to prepare for rebellions. This discrimination between the old and the new retainers