Built in 1841 by the ninth Lord of Mito, Nariaki Tokugawa, the Kodokan Hall was the largest school during the Edo period. The school pioneered in lecturing on such varied subjects as medicine,mathematics, and astronomy, as well as Confucian studies and military arts. Through its scholars, the school had a great influence on the movement to "Revere the Emperor and Expulsion of Foreigners" toward the end of the Edo Period.