Takechi Zuizan (武市 瑞山?, October 24, 1829 – July 3, 1865), also known as Takechi Hanpeita (武市 半平太?), was a samurai of the Tosa han during the Bakumatsu period in Japan. As leader of the Tosa Kinnōtō , which supported the Sonnō Jōi ("revere the Emperor and expel the barbarians") movement, he tried to take control of the Tosa Han and receive the support of Sakamoto Ryōma, but was arrested for the assassination of Yoshida Tōyō and forced to commit seppuku. He gave orders to Okada Izō, one of the best known assassins of the Bakumatsu period.
Jansen, Marius B. Sakamoto Ryoma and the Meiji Restoration. Princeton: Princeton UP, 1961. Print.