Is it dangerous to live in japan where rh negative blood is very rare? what if i need blood or shot if pregnant in the future? i'm a

Not really: This is a very good question. In much of Asia and Africa, Rh negative blood is rare. If you require emergency transfusion, the worst that can happen is that you'll be given Rh positive units and you them may or may not get a relatively mild hemolytic illness a few days later. The blood banks in the cities should actively recruit Rh negative donors to keep supplies available. Best wishes.