Or emishi, (y)ezo. Indigenous inhabitants of Japan who were gradually pushed back to the northern island of Hokkaido by Japanese expansionist wars. Hokkaido was fully colonised by the Japanese only in the 20th century. Ainu culture is different from Japanese, but there have been many cross-influences in the long course of Japanese-Ainu relations in the Japanese islands. Ainu festivals include kotan matsuri (community festivals) similar to ujigami festivals. The Kushiro kotan matsuri dedicated to the deity of lakes now takes place in Kushiro, Hokkaido on the second Sunday in September. The best-known Ainu festival is the iyomante or kuma matsuri (bear sacrifice festival).
A Popular Dictionary of Shinto. Brian Bocking.