WW2 was the culmination of Japan's semi-conscious effort to speed run the transition from feudal backwater to first rate world power. Considering all the stuff

WW2 was the culmination of Japan's semi-conscious effort to speed run the transition from feudal backwater to first rate world power. Considering all the stuff they had pulled off up until that point and that they exited WW2 with their national identity and power structures intact I don't think it's that surprising that they pulled off the transition from imperial government to constitutional democracy with an imperial figurehead.