One is the "Emishi-Ainu Theory," which insists that the Emishi and Ainu were identical, and the other is the "Emishi-Frontiersmen Theory," in which the Emishi were part of the Japanese people.
蝦夷をアイヌ人とする蝦夷アイヌ説と、蝦夷を日本人の一部とする蝦夷辺民説である。