Koshamain's War
Koshamain's War was an armed struggle between the Ainu and Wajin that took place on the Oshima Peninsula of southern Hokkaidō, Japan, in 1457. Escalating out of a dispute over a sword, Koshamain and his followers sacked twelve forts in southern Ezo, before being overcome by superior forces under Takeda Nobuhiro. The principal record of the conflict is Shinra no Kiroku.