Ii Naosuke, Chief Minister of the Tokugawa Shogunate was the assassinated on March 24, 1860 by rōnin samurai of the Mito Domain and Satsuma Domain, outside the Sakurada Gate of Edo Castle. Ii Naosuke was a proponent of the reopening of Japan after more than 200 years of seclusion, was widely criticized for signing the 1858 Treaty of Amity and Commerce with the United States Consul Townsend Harris and, soon afterwards, similar treaties with other Western countries. From 1859, the ports of Nagasaki, Hakodate and Yokohama became open to foreign traders as a consequence of the Treaties.