Why not start with some geographical data. Japan is archipelago composed by 4 main islands: Hokkaido, Honshu, Shikoku and Kyushu. The main island, Honshu, is divided in 5 area: Tohoku region, Kanto region, Chubu region, Kansai (or Kinki) region and Chugoku region. The 2 major regions are Kanto plain where Tokyo is located, and the Kansai plain where Osaka is located.
Let's visit Japan in photos: click on the interactive map to discover one of these regions.