WI: Ainu and Japanese split the difference

[JimmyJimJam]

WI the Japanese assimilation of the Ainu was not quite so complete, and the Ainu and they divide the islands roughly 50%/50%? Would the result be almost impossible to imagine?

 

[strangeland]

it's quite hard for me to imagine what an Ainu state would look like to be honest. Does anyone have ideas?