The Japanese Civil War, known in Japanese as the Boshin War, was the last civil war in Japan before the collapse of the feudal system. Seeds for the war were planted when the Shogun Tokugawa Ienari announced plans to modernise and industrialise Japan with the help of western nations. Many daimyo were against this, and formed a 'reactionary coalition' known as the Domain Alliance to establish a new isolationist shogunate under Shizamu Narioko. After Shizamu was declared Shogun by the Domains, Tokugawa declared war on the Alliance, beginning the civil war.
In early 1808, an American convoy carrying supplies and military advisors to Edō was attacked by the Domain Alliance, creating a pretext for direct American intervention in the war. With American and limited Spanish support, the Tokugawa shogunate toppled the Alliance and restored rule from Edō in the rebelling Domains.
Currently, a peace treaty is being negotiated in Sapporo.