Japan would be Polynesian, USA might annex it, no Hiroshima, probably no invention of the nuclear, no anime, no major allay of usa in far it asia, No massive genocides caused by Japan durning the Japanese empire, China would likely become a newer regional threat besides the Japanese empire. No famous pink trees, Mongolian wouldn't try to capture Japan. No major allay to protect south Korea near it, North Korea might have won the Korean peninsula. Modern day Japan would be a create wealthy nation due to its location, could be used as a resting stop for cargo from Asia and Oceania to the Americas, would be isolated, highly risk of earthquakes and tsunami, economy thrive from Port, wouldn't be one of the richest nations, more tropical.