As the matter had been touched in another topic and as I can't agree the opinions mentioned there, I think I should open this topic.
I guess every country has a dark heredity, so here is one for Japan: Colonialism, War and War crimes in Asia. Details can be found in Wikipedia (
http://en.wikipedia.org/wiki/Japanese_war_crimes), for now let me just list the headlines:
Mass killings, Experiments on humans and biological warfare, Use of chemical weapons, Preventable famine, Torture of Prisoners of war, Cannibalism, Forced labor, Comfort women (also termed Sex Slaves), Looting.
I agree that Japan today is not the Japan it was at that time. But I still feel it has to face its history.
I agree that dialogue with China is very difficult under current conditions which do not permit an open discussion in China. On the other hand it is very difficult for me to understand why some people in Japan insist on such a provocations as visiting Yasukuni shrine (shrine for war deads including some war criminals).
I don't think this issue is past and forgotten - it is very present in Asia and an obstacle in bilateral relations. I understand that the Asian context didn't allow the same development as in Europe, where we reached a shared interpretation of World War 2 to quite some extend; still for the very sake of Asia and Japan itself we should think about it...