In a plot to eliminate the Japanese Soga clan, Prince Naka no Ōe assassinated Soga no Iruka (depicted), beginning the Isshi incident.

The Soga clan was one of the most powerful aristocratic kin groups (uji) of the Asuka period of the early Japanese state—the Yamato polity—and played a major role in the spread of Buddhism in Japan. Through the 5th and 7th centuries, the Soga monopolized the kabane or hereditary rank of Great Omi and was the first of many families to dominate the Imperial House of Japan by influencing the order of succession and government policy.

Emperor Tenji , known first as Prince Katsuragi and later as Prince Nakano Ōe until his accession, was the 38th emperor of Japan who reigned from 668 to 671. He was the son of Emperor Jomei and Empress Kōgyoku, and his children included Empress Jitō, Empress Genmei, and Emperor Kōbun.

Soga no Iruka was the son of Soga no Emishi, a statesman in the Asuka Period of Japan.

The Isshi incident was a successful plot by Nakatomi no Kamatari, Prince Naka no Ōe and others who conspired to eliminate the main branch of the Soga clan, beginning with the assassination of Soga no Iruka. It takes its name from the zodiological name of the year 645 during which the Taika Reform, a transformative event in Japanese Imperial history, occurred.