What are the hidden place in Japan i shouldn't miss out on?

Gotta do the hot springs and autumn foliage in Kyushu! Kurokawa Hot Springs and Yufuin are world class, but still a treasured secret!

It's no secret hidden place except from every US president since WWII because they've never gone there, but you definitely have to check out the Peace Parks in Hiroshima and Nagasaki -- That will definitely get you thinking about the stupidity of war.

And if you had to choose between Hiroshima and Nagasaki, I'd say check out Nagasaki as it's just as poignant, and later, you could visit Nagasaki which has an edge, I think, in historical significance and scenery.

You might also want to visit Gunkamjima just outside Nagasaki harbor if you're into post-apocalyptic type scenery (A ghost island which was once the most densely populated place on earth.)

Have a wonderful trip!