The revenge of the Forty-seven Ronin (四十七士, Shi-jū-shichi-shi^?), also known as the Forty-seven Samurai, the Akō vendetta, or the Genroku Akō incident (元禄赤穂事件, Genroku akō jiken^?) took place in Japan at the start of the 18th century. One noted Japanese scholar described the tale as the country's "national legend." It recounts the most famous case involving the samurai code of honor, bushidō.

The story tells of a group of samurai who were left leaderless (becoming ronin) after their daimyo (feudal lord) Asano Naganori was forced to commit seppuku (ritual suicide) for assaulting a court official named Kira Yoshinaka, whose title was Kōzuke no suke. The ronin avenged their master's honor after patiently waiting and planning for two years to kill Kira. In turn, the ronin were themselves forced to commit seppuku for committing the crime of murder. With much embellishment, this true story was popularized in Japanese culture as emblematic of the loyalty, sacrifice, persistence, and honor that all good people should preserve in their daily lives. The popularity of the almost mythical tale was only enhanced by rapid modernization during the Meiji era of Japanese history, when it is suggested many people in Japan longed for a return to their cultural roots.