I'm not sure that is a good choice at all. Osaka along with several of your other choices are far too South I think. Even Hokkaido isn't far enough North. The best choices I think are New Zealand, Greenland, Sweden, and Denmark. That is assuming Russia hasn't invaded by then. Also, as SE Asia's water runs out do to the melting glaciers I wouldn't be surprised if China invades Japan. Though I hope not since my family and I live in Nagoya.

Also, if what is happening in the North Atlantic plays out like some scientists think it might, then all of these except New Zealand countries as well as Slovenia, France, and Switzerland might be frozen wastelands.