As Japan is a pretty large country, there are many unique flavors or Food unique to its locality. For example, Osaka is famous for its Takoyaki, Okonomiyaki, and Kushikatsu. Hakata has its own variant of ramen, and Mentaiko is a local speciality of Fukuoka.
If you ever have the opportunity to stay in an authentic Japanese Ryokan, with an authentic Japanese family, jump at it! While the capsule hotels and bright lights of Tokyo may have recently stolen the limelight in terms of popular tourism, there is nothing quite like getting your hands on a truly traditional Japanese experience.