The Boshin War ("War of the Year of the Dragon"), a civil war in Japan, fought from 1868 to 1869 between forces of the ruling Tokugawa shogunate and those seeking to return political power to the imperial court, has its its origins in dissatisfaction among many nobles and young samurai with the shogunate's handling of foreigners following the opening of Japan the prior decade.

An alliance of southern samurai and court officials secures the cooperation of the young Emperor Meiji, who declares the abolition of the two-hundred-year-old shogunate.

Military movements by imperial forces and partisan violence in Edo lead Tokugawa Yoshinobu, the sitting shogun, to launch a military campaign to seize the emperor's court at Kyoto.

The military tide rapidly turns in favor of the smaller but relatively modernized imperial faction, and after a series of battles culminating in the surrender of Edo, Yoshinobu personally surrenders.

The Tokugawa remnant retreats to northern Honshū and later to Hokkaidō, where they establish the Ezo republic.

Defeat at the Battle of Hakodate breaks this last holdout and leaves the imperial rule supreme throughout the whole of Japan, completing the military phase of the Meiji Restoration.Around 120,000 men are mobilized during the conflict, and of these about 3,500 are killed.

In the end, the victorious imperial faction abandons its objective of expelling foreigners from Japan and instead adopts a policy of continued modernization with an eye to eventual renegotiation of the Unequal Treaties with the Western powers.

Due to the persistence of Saigō Takamori, a prominent leader of the imperial faction, the Tokugawa loyalists are shown clemency, and many former shogunate leaders are later given positions of responsibility under the new government.The Boshin War testifies to the advanced state of modernization already achieved by Japan barely fourteen years after its opening to the West, the already high involvement of Western nations (especially the United Kingdom and France) in the country's politics, and the rather turbulent installation of Imperial power.

Over time, the war has been romanticized by Japanese and others who view the Meiji Restoration as a "bloodless revolution," despite the number of casualties.

Various dramatizations of the war have been made in Japan, and elements of the conflict were incorporated into the 2003 American film The Last Samurai.