Under these circumstances, powerful domains in the western Japan such as Satsuma Domain, Choshu Domain, who repeated political strifes, concluded an alliance (the Satsuma-Chochu Alliance) through the intermediation of Ryoma SAKAMOTO and Shintaro NAKAOKA.
このような情勢下、薩摩、長州ら政争を繰り返していた西国雄藩は坂本龍馬、中岡慎太郎の周旋により、同盟を締結（薩長同盟）した。