One theory has been influenced by the results of the Genpei War (1180 – 1185). Until the Heian period, the Nishiki flag (Nishiki no mihata 錦の御旗), a symbol of the Imperial Court, had gold and silver moon circles on a red background. At the end of the Heian era, they used the red flag, which is the color of their flag (Taira clan), calling themselves a government army, while Genji (Minamoto clan), in opposition to it, fought the Genpei war with the white flag. Since ancient times, the sun has been a symbol of national unity because of the close relationship between national rule and the sun. When Taira was destroyed and the samurai government was established by Genji, successive shōguns claimed to be descendants of Genji, and it was said that the Hinomaru of "Shirachikamaru" (白地赤丸, red circle on white background) had been inherited as a symbol of those who achieved the unification of the country. In Japan, "red and white" has been regarded as a joyous color scheme. One theory is folklore that there is a sense of Sacred–profane dichotomy (sacred = red, profane = white), and that this is also derived from the Genpei War.