In 1899, the Japanese government passed an act labeling the Ainu as former aborigines, with the idea they would assimilate—this resulted in the land the Ainu people lived on being taken by the Japanese government, and was from then on under Japanese control. Also at this time, the Ainu were granted automatic Japanese citizenship, effectively denying them the status of an indigenous group.

While at the time the process was openly referred to as colonization (“takushoku” 拓殖), the notion was later reframed by Japanese elites to the currently common usage “kaitaku” (開拓), which instead conveys a sense of opening up or reclamation of the Ainu lands. During this time the Ainu were forced to learn Japanese, required to adopt Japanese names and ordered to cease religious practices such as animal sacrifice and the custom of tattooing.

The 1899 act mentioned above was replaced in 1997—until then the government had stated there were no ethnic minority groups. It was not until June 6, 2008 that Japan formally recognised the Ainu as an indigenous group.

According to the community, their tragedy is comparable in scale and intensity only with the genocide faced by the indigenous people of the Americas.