Farthest Island North. Used to be sparsely populated by Ainu but in the last 100 years, the Government has developed the area so that people from around Japan have migrated there. Hence, Hokkaido has a mixed population with a very young culture but all the areas have Ainu names. The girls are famous for their light skin and beauty. Although known as a seafood haven, oddly, one of the most popular dishes is grilled Mutton which is called Genghis Khan. Hokkaido is one of the coldest cities on earth, yet people walk around in shorts inside their homes because gas is subsidized by the government so people keep their homes a comfortable 80F even in the coldest winters. During the short warm summers, people like to go camping at the beach for several days and have Japanese style BBQ.
In contrast, the closest area to Hokkaido on the northern tip of the main Island of Honshu, Aomori prefecture has a very old and distinct culture. The dialect has drifted to the point were other Japanese cannot understand it - to me, it sounds like Korean. The people are known for their quiet manner and strong resolve. They are also known to be very efficient and frugal; Often a whole sentence can be compressed to a few words, Aomori women spend the least on underwear in all of Japan.
The Japanese version of New Yorker; metropolitan, a bit snobbish and cold, Tokyo people think they are the center of it all for which in many ways Tokyo is. Tokyo tends to look down on other parts of Japan so people who move to Tokyo try and hide their regional mannerisms and dialect. To be found out is like everyone thinking one is a country bumpkin. Tokyo dialect and mannerism are considered proper and standard of Japan.
The former capital of Japan, Kyoto is Japan's New England. Rich in traditional culture and landmarks, the people are blue blood snobbish. To the foreigner, Kyoto is famous for its Geisha but to the Japanese, Kyoto is known for its indirect communication(Tatemai). For example, "Wow, you have such pretty hair" could be interpreted as "the only thing I can compliment you on is your hair". Oddly for the place most known for traditional Japanese culture, Kyoto residence eat the most bread in all of Japan.
This is the odd man out in Japan. Osaka tends to be "me" oriented compared to Tokyo or Kyoto, free to tell what they think and feel as well as criticize others. Osaka people are very open and joke around a lot. Tend to be more relaxed than other areas of Japan yet very hardworking and business oriented. They are known for their lack of fashion sense preferring their own style. Their food culture is wheat based instead of rice-based - Osaka is the home of Okonomiyaki and Takoyaki. Osaka people feel that both Tokyo and Kyoto look down on them.
This is the Texas of Japan. The people are friendly and macho and hard drinkers. Basically a blue-collar culture, Kyushu people are not shy and love to argue and fight. The Kyushu dialect is one of the three main root dialects in Japan; western, eastern and Kyushu. Though not as famous around the world as Kobe and Matsusaka beef, Kyushu actually has the most Wagyu brands in all of Japan. Kyushu is home to the famous Kurobuta Berkshire pig and some of the top jidori chickens.
The Hawaii of Japan. People who live on small islands eat a lot of pork. Okinawans are very laid back and easygoing. Whereas 15 minutes late is very offensive in Tokyo, two hours late is no problem in Okinawa. Okinawa like Nagasaki is strongly Chinese influenced but the people are not of Chinese descent - they are strongly Jomon heritage. Okinawa has a strong American influence do the many decades of military bases on their islands. They use a lot of spam and have unique fusion dishes like Taco Rice.