in Japanese history, war of imperial succession that brought an emperor with a secure military base to the Japanese throne for the first time in history. The war strengthened the power of the imperial family at the expense of powerful associated clans, such as the Nakatomi and Soga.

The conflict erupted following the death of the emperor Tenji in AD 672, when Prince Ōtomo was elevated to the throne as the emperor Kōbun through the efforts of the aristocratic clans that had resisted Tenji's centralization measures. Prince Ōama, brother of the deceased emperor, gathered together his own military forces and defeated Ōtomo at his capital in Ōmi province (modern Shiga prefecture). Ōama then succeeded to the throne as the emperor Temmu, making his new capital at Asuka in Yamato province (modern Nara prefecture), which was removed from the influence of the Nakatomi and Soga clans.