Oishi Yoshio

Statue of Ōishi Yoshio at Sengakuji in Tokyo

Ōishi Yoshio (大石良雄 1659 - March 20, 1703) was the karō of the Akō han in Harima Province (now Hyogo Prefecture), Japan (1679 - 1701). He is known as the leader of the Forty-seven Ronin in their 1702 vendetta and thus the hero of the Chushingura. He is often referred to by his title, Ōishi Kuranosuke (大石内蔵助).

He served Asano Naganori as the head karō. When Asano committed seppuku as punishment for his failed attempt to kill Kira Yoshinaka in Edo castle and the Tokugawa shogunate abolished the house of Asano in Akō, Ōishi was in Akō and managed all its administrative issues. He persuaded other samurai to vacate the castle to the agents of the Shogunate.

He attempted to get the permission to re-establish the house of Asano but failed. In January 1703 (by the old Japanese calendar, December 14) he, with 45 other Akō ronin, attacked Kira at his residence in the Honjo neighborhood of Edo. Kira was killed and decapitated. The 46 ronin went to Sengaku-ji in Shinagawa where Naganori was buried and there they were arrested.

He and the other ronin were sentenced to commit seppuku. Since it was an honorable sentence rather than merely decapitation, everyone accepted this sentence as a honor.