The Satsuma and Choshu Domains allied with Tomomi IWAKURA to initiate the Decree for the Restoration of Imperial Rule in 1868, and when the new government was formed, the Saga Domain was also involved and Shinpei was dispatched to Kyoto with Taneomi SOEJIMA.
薩摩藩、長州藩は公家の岩倉具視と結び明治元年（1868年）の王政復古の大号令を行い、新政府が誕生すると佐賀藩も参加し新平は副島種臣とともに京都に派遣される。