It was a variant of Proletarian Revolution Theory that came to light shortly after the revision of the Treaty of Mutual Cooperation and Security Between the United States and Japan, focusing on the Ainu.
The actions and writings of Japanese left-wing thinker Ota Ryu in particular made Ainu Revolution Theory well known.
They believed that the lumpenproletariat could be the main body of the revolution, and that the Ainu people of Japan were also included inside this group.
The Sapporo Olympics held in 1972 helped inspire militants to become more active in Hokkaido.
Yuki became acquainted with Ota around 1972, accompanying him when he read out a public questionnaire at the Japanese Anthropological and Ethnic Association Congress at Sapporo Medical University.