Ii Naosuke (November 29, 1815 – March 24, 1860)was daimyo of Hikone (1850–1860) and also Tairo of Tokugawa Shogunate, Japan, a position he held from April 23, 1858 until his death on March 24, 1860. He is most famous for signing the Harris Treaty with the United States, granting access to ports for trade to American merchants and seamen and extraterritoriality to American citizens. He was also an enthusiastic and accomplished practitioner of the Japanese tea ceremony, in the Sekishuryu style, and his writings include at least two works on the tea ceremony.
Under Ii Naosuke’s guidance, the Tokugawa shogunate navigated past a particularly difficult conflict over the succession to the ailing and childless Tokugawa Iesada. Ii Naosuke managed to coerce the Tokugawa Shogunate to its last brief resurgence of its power and position in Japanese society before the start of the Meiji-era. Ii was assassinated in the Sakuradamon incident by a group of 17 Mito and 1 Satsuma samurai on March 24, 1860