Satchō Alliance

In the 1860s, Satsuma tended to take a moderate position towards maintenance of the status quo, whereas Chōshū had become the center of an uprising aimed at overthrowing the government.

Satsuma, on the other hand, had developed a substantial arms trade with Great Britain via Thomas Glover, a Scottish merchant affiliated with Jardine Matheson.

At the suggestion of Sakamoto, Saigo helped broker an agreement to supply Chōshū with the weapons it needed to fight the Tokugawa shogunate.

On March 1, 1866, the Shogunate demanded the retirement and confinement of Chōshū daimyō Mōri Takachika and the reduction of domain revenues by 100,000 koku.

During the subsequent Boshin War of 1868–1869, the imperial armies which finally overthrew the Shogunate were primarily samurai from the Satchō alliance.