From Hokkaido, A History of Ethnic Transition and Development on Japan’s Northern Island, by Ann B. Irish (McFarland, 2009), p. 47:
A frightening uprising with long-lasting ramifications erupted in 1789. Just as Shakushain remains a hero to many Ainu, the shocking Wajin [= ethnic Japanese] response to the 1789 events makes them a continuing spur to Ainu nationalism. At that time, Ainu were restricted to trading at posts chartered to contractors by the Matsumae. It was often these contractors who cheated or injured the Ainu. One of the worst offenders was Hidaya Kyubei, who operated in southwest Hokkaido and on Kunashir Island in the Kurils. A Hidaya man had come to Ezo as early as 1702 and obtained permission from the Matsumae to set up a lumber business. He brought workers to Ezo with him, sent the lumber his workers cut to Honshu cities, and paid large amounts to the Matsumae for the privilege. In return, his family obtained trading posts and amassed wealth. His grandson, Hidaya Kyubei, expanded his operations, in 1774 opening a trading post on Kunashir. Over the next few years he gained more and more control over the Ainu there, until they were reduced from a self-reliant society living in a traditional manner to the near-slavery and near-starvation seen at Hidaya’s other posts. Wajin frequently threatened Ainu with death or drowned their dogs. Ainu who could no longer work were killed, it was reported. Women were raped and men who tried to resist Hidaya depredations poisoned. Even Aoshima Shunzo, an Edo official sent later to probe the conflict and its causes, found that some blame lay with the Hidaya family, who forced Ainu in their region to work at rates of remuneration impossible to support life.
In 1789, a group of young Ainu, incensed because they believed that several Ainu died after Hidaya officials had given them poisoned sake, instigated hostilities, usually known today as the Menashi-Kunashir War. Ainu attacked Wajin at the Kunashir trading post, on the Ezo mainland, and on a ship in the area, leaving seventy-one dead. The young Ainu apparently planned their assault carefully, having prepared defensive measures, but local Ainu leaders who had been away at the time of the attack returned and persuaded the rebels to desist. To the elders, good relations with Wajin remained crucially important, as Ainu livelihood depended on them. Meanwhile, news got back to the Matsumae, who sent a large force to the affected region near Cape Nosappu east of Nemuro, including troops from other domains ordered by the shogunate to aid the Matsumae. The soldiers captured the eighty-seven Ainu they felt were responsible for the outbreak. Executiions of the leaders began. One of the Ainu let out a war-cry; the Wajin soldiers reacted in panic and speared prisoners randomly, leaving thirty-seven dead. Their heads were taken for display at the Matsumae capital. Hidaya lost his contract and the Matsumae issued new regulations for trading with Ainu; some improvement may have resulted.
This was the last serious Ainu challenge to the Matsumae, but as Wajin immigration continued, so did Ainu resentment.
During our recent trip to Hokkaido, the young Japanese tour guide on our bus to Cape Nosappu told the story of this uprising on our way back to Nemuro.