The or Menashi-Kunashir battle took place in 1789 between the Ainu and the Wajin (also called the Yamato people, i.e. the ethnic Japanese) on the Shiretoko Peninsula in Northeastern Hokkaido.
It began in May 1789, when the Ainu attacked the Wajin on Kunashir Island and parts of the Menashi District, as well as at sea. More than 70 Wajin were killed. The Wajin executed 37 Ainu identified as conspirators and arrested many others. The reasons for the revolt are not entirely clear, but they are believed to include a suspicion of poisoned sake being given to Ainu in a loyalty ceremony and other objectionable behavior by Wajin traders.
The battle is the subject of Majin no Umi, a children's novel by Maekawa Yasuo that received the Japanese Association of Writers for Children Prize in 1970.
A similar large-scale Ainu revolt against Wajin influence in Yezo was Shakushain's Revolt, which lasted from 1669 until 1672.