Anticipating the night view in Japan is one of the highlights of your stay in Japan.
Where should you go?
It depends where do you want to enjoy the night view.
Then, there are three types of night views in Japan.
The first type is the typical from the observatory decks of towers or skyscrapers such as Tokyo Skytree, Tokyo tower or Tokyo Metropolitan Government building.
Second one is at the top of the mountains or hills. Examples are Hakodate, Nagasaki and Kobe. You have to go up to peak by bus, cable car or aerial tramway. I think no tourists visiting Hakodate or Nagasaki go back home without enjoying the magnificent views.
The last type is from the Ferris wheels. The height of the Ferris wheels are not so high as observatory deck of towers or buildings but if you want to enjoy the view of the bay or port, Ferris wheel is a good choice.