Japan is divided into 8 regions: Hokkaido, Tohoku, Kanto, Chubu, Kinki, Chugoku, Shikoku, Kyushu-Okinawa. Within each region their are different dialects spoken; if you were is the Kanto region and went to the Kinki region a person could tell you are not around these parts. Each regions also varies in cultures and traditions, even though they are all in Japan each part can have their unique style of food or clothes. In Japan's regions there are also different environments and depending on that the people there know what kind of resources they have and know what they will need. Each region can have something specific they grow or cultivate in; that could help another region because it could be lacking of that thing. Regions in Japan are different in many ways but they are still apart of Japan.
Hokkaido- Fishing and having forests are important for agriculture in that region. Its also has a great night view
Tohoku- Largest mountainous region, 65% of land is made of rice paddy fields and it has many industrial activities going on
Kanto- climate is mainly mild, famous for the culture and entertainment, Tokyo is in the Kanto region
Chubu- has some of the longest rivers, has many agricultural products, Mt Fuji is in the Chubu region
Kinki- once the capital of Japan (emperors lived there), it is famous for its culture and history
Chugoku- is mountainous, coastal plains, was hit by the atomic bomb in WWII
Shikoku- various islands, steep mountains, has two chain bridges
Kyushu-Okinawa- hot springs, major sightseeing spots, warm climate