Enperor dosen't participate in national politics, he is just a symbol. Though why he is there? I don't know the answer, but I think that he do emotional support of Japanese people.
It saw when emperor visited Fukushima after disaster. I watched the spectacle on TV.
Then, people were much appreciating him though he don't have poritical power in essence.Maybe he has invisibility power.
Emperor problem is heir ploblem.So far only man has served emperor for a long time.Suprisingly, There isn't a son, but girl is there. Then goverment is discussing that correcting imperial house low.But It is changing long history.It should discuss deep.
Because, emperor has mysterious power.