<P> It followed a coup d'état by the Taira in 1179 and call to arms against them led by the Minamoto in 1180 . The ensuing battle of Uji took place just outside Kyoto, starting a five - year - long war, concluding with a decisive Minamoto victory in the naval battle of Dan - no - ura . </P> <P> The Genpei War was the culmination of a decades - long conflict between the two aforementioned clans over dominance of the Imperial court, and by extension, control of Japan . In the Hōgen Rebellion and in the Heiji Rebellion of earlier decades, the Minamoto attempted to regain control from the Taira and failed . </P> <P> In 1180, Taira no Kiyomori put his grandson Antoku (then only 2 years of age) on the throne after the abdication of Emperor Takakura . Emperor Go - Shirakawa's son Mochihito felt that he was being denied his rightful place on the throne and, with the help of Minamoto no Yorimasa, sent out a call to arms to the Minamoto clan and Buddhist monasteries in May . However, this plot ended with the deaths of Yorimasa and Mochihito . </P> <P> In June 1180, Kiyomori moved the seat of imperial power to Fukuhara - kyō, "his immediate objective seems to have been to get the royal family under his close charge ." </P>

The minamoto and taira claimed status from their relationship to the