岩倉使節団
After the return of the Iwakura Mission and the rejection of the "Seikanron" proposals to invade Korea in October 1873, Soejima resigned from the government. He later joined Itagaki Taisuke and Eto Shimpei in forming the "Aikoku Koto" political party. On a visit to China in 1876, he was received with high honors by the mandarins by reason of his scholarship, and he became private adviser of the emperor.