The Battle of Shigisan, a battle fought in 587 between Soga no Umako and Mononobe no Moriya at the riverside of the Ekagawa river in Kawachi Province, Japan near Mount Shigi, practically exterminates the Mononobe clan, the most powerful opponent of Buddhism.
The Soga clan, which has intermarried with the royal Yamato, had fought the Mononobe and Nakatomi clans over influence in selecting a new successor for the Japanese throne, after emperor Yōmei died.
The Soga favor importing Buddhism from the Asian mainland, described there as the religion of the most civilized.
The Mononobe and Nakatomi hold that Buddhism would be an affront to the gods.
The Soga win the civil war and Sushun, age sixty-six, becomes the thirty-second emperor of Japan.
