When Aritomo YAMAGATA's plan of establishing goshimpei (army to convoy the Emperor) surfaced, Okubo went to Kagoshima as the Imperial envoy along with Tomomi IWAKURA and successfully persuaded Saigo to serve the government in order to establish goshimpei.
折りしも山縣有朋の御親兵設置構想が浮上すると大久保は岩倉具視とともに勅使として鹿児島に入って西郷説得に成功し、御親兵設置の企画推進のための出仕同意を取り付けたのである。