Genpei War

The Genpei War was a civil conflict fought in Japan from 1180 to 1185 between the Taira (Heike) and Minamoto (Genji) clans for control of the imperial court and effective rule of the country, ending the Taira's decade of dominance and paving the way for Japan's first shogunate. Fighting broke out after Minamoto no Yorimasa's failed 1180 rebellion against Taira clan head Taira no Kiyomori, and though Yorimasa was killed, his call to arms was taken up by Minamoto no Yoritomo, who rallied eastern warrior clans against the Taira over the following years. Yoritomo's half-brother Minamoto no Yoshitsune led the decisive campaigns, defeating Taira forces at Ichi-no-Tani and Yashima before annihilating the Taira fleet, along with the child emperor Antoku, at the naval Battle of Dan-no-ura in 1185. Yoritomo's victory established him as Japan's first shogun in 1192, founding the Kamakura shogunate and beginning nearly seven centuries of military government that would define Japanese politics until the nineteenth century.