I recommend visiting - Hakodate, Japan
The port city of Hakodate on Hokkaido, Japan's northernmost island is off the beaten track but becoming more popular now that the Shinkansen (bullet train) connects it with Tokyo.
Hakodate was one of the first Japanese ports to open to international trade and it has interesting connections to Russia as well as impressive seafood. You can even catch your own squid at the morning market. After exploring the historical parts of Hakodate I'd recommend seeing the view from Mount Hakodate by night (get there early to beat the crowds), or heading north to Onuma Quasi National Park, renting a bike and cycling your way around the lake.