But, if we leave race out of it… the fact that nearly all land has been taken by violence undermines the idea of “well this was violently transferred” in principle, I don’t think it makes the case that the Japanese government cannot opt to restrict immigration, since all land ownership is effectively created by force of arms anyway.  Even by the basis of “well some specific Japanese might object,” there is almost never going to be complete unity of opinion in government, so their objection does not necessarily invalidate the entire project, especially if emigration is permitted and there are states to emigrate to.  

In fact, there is a thriving market in governance already, with hundreds of options to choose from.  As criticisms of “but the market doesn’t have what I want” can be shut down as the market not being obligated to supply it, so too, here.