Iwakura Tomomi
The mission was named after and headed by Iwakura Tomomi in the role of extraordinary and plenipotentiary ambassador, assisted by four vice-ambassadors, three of whom (Ōkubo Toshimichi, Kido Takayoshi, and Itō Hirobumi) were also ministers in the Japanese government. The historian Kume Kunitake as private secretary to Iwakura Tomomi, was the official diarist of the journey. The log of the expedition published in 1878 in five volumes as "Tokumei Zenken Taishi Bei-O Kairan Jikki" (特命全権大使米欧回覧実記), provided a detailed account of Japanese observations on the United States and rapidly industrializing Western Europe.