First Battle of Uji Launches Japan's Genpei War
During the late Heian period in Japan, the Taira clan held dominant influence at the imperial court, marginalizing rival Minamoto families. Prince Mochihito, backed by Minamoto no Yorimasa, issued a call to arms against the Taira in an attempt to restore Minamoto power. On June 20, 1180, Taira forces intercepted and defeated the rebels at the Uji River near Kyoto after the plot was discovered. Prince Mochihito and Yorimasa were killed in the fighting. Though a Taira victory, the clash ignited the broader Genpei War that would last until 1185.
Why it matters: The battle marked the opening of the Genpei War, which ended Taira dominance and established the Kamakura shogunate under Minamoto no Yoritomo. It accelerated the shift from court aristocracy to warrior rule, defining Japan's medieval political structure for centuries.