was a Japanese statesman who played an important role in the Meiji Restoration, influencing opinions of the Imperial Court.
After Tairō Ii Naosuke was assassinated in 1860, Iwakura supported the Kobugattai Movement, an alliance of the Court and the Shogunate. The central policy of this alliance was the marriage of the Shogun Tokugawa Iemochi and Princess Kazu-no-Miya Chikako, the younger sister of the Emperor Kōmei. Samurai and nobles were supported the more radical Sonno joi policy saw Iwakura as a supporter of the Shogunate, and put pressure on the Court to expel him. As a result Iwakura left the Court and moved to Iwakura, north of Kyoto.
With Okubo Toshimichi and Saigō Takamori, on 3 January 1868, he engineered the seizure of the Kyoto Imperial Palace by forces loyal to Satsuma and Chōshū, thus initiating the Meiji Restoration.
After the establishment of the Meiji government, Iwakura played an important role due to the influence and trust he had with Emperor Meiji. He was largely responsible for the promulgation of the Five Charter Oath of 1868, and the subject abolition of the han system.
Soon after his appointment as Minister of the Right in 1871, he led the two-year around-the-world journey known as the Iwakura mission, visiting the United States and several countries in Europe with the purpose of renegotiating treaties and gathering information to help effect the modernization of Japan. On his return to Japan in 1873, he was just in time to prevent an invasion of Korea (Seikanron). Realizing that Japan was not in any position to challenge the western powers in its present state, he advocated strengthening the imperial institution, which he felt could be accomplished through a written constitution and a limited form of parliamentary democracy. He ordered Inoue Kowashi to begin work on a constitution in 1881, and ordered Ito Hirobumi to Europe to study various European systems.