The Soviet Union did seize Sakhalin from the Japanese empire, which is part of the Japanese island chain (although it has more Ainu and Koreans than Yamato and so was probably hostile to the empire to begin with)
A great movie that illustrates the friendship between a red army soldier and an ainu man is Kurosawa's Dersu Uzala. Surprisingly heartwarming and low-key, although still dramatic and moving in its own way
The Soviet Union did seize Sakhalin from the Japanese empire, which is part of the Japanese island chain (although it has more Ainu and Koreans than Yamato and so was probably hostile to the empire to begin with)
A great movie that illustrates the friendship between a red army soldier and an ainu man is Kurosawa's Dersu Uzala. Surprisingly heartwarming and low-key, although still dramatic and moving in its own way