Japan is divided into 8 regions and 47 prefectures.
Japanese 8 Regions and 47 Prefectures in Japan
Tohoku: Aomori, Akita, Fukushima, Iwate, Miyagi, Yamagata
Kanto: Chiba, Gunma, Ibaraki, Kanagawa, Saitama, Tochigi, Tokyo
Chubu: Aichi, Gifu, Fukui, Ishikawa, Toyama, Shizuoaka, Nagano, Yamanashi
Kansai: Mie, Shiga, Hyogo,Wakayama, Nara, Osaka, Kyoto
Chugoku: Okayama, Shimane, Tottori, Hiroshima, Yamaguchi
Shikoku: Ehime, Kagawa, Kochi, Tokushima
Kyushu: Saga, Oita, Okinawa, Kumamoto, Kagoshima, Nagasaki, Miyazaki, Fukuoka
We often use the region names when we explain where we are from as well.
We usually use Kansai and Kanto since they are the most populated and culturally distinct regions.
We compare Kansai and Kanto quite oftenly. For instance, I am from Osaka and Osaka is in the Kansai region and we speak Kansai dialect: “関西弁（かんさいべん）” when we talk so we can tell easily if the person is from Kansai or Kanto. The food and overall personalities in both the regions are a lot different as well. I find Kansai people more funny and friendly. In Kanto especially in Tokyo, people are more quiet and cold maybe because work is very important in the biggest city in Asia.
When we meet new people in Japan we usually ask the person’s “出身（しゅっしん）” meaning the place where the person is from to start off conversations.
Ex)A: “Takuru where do you come from?” → 「たける、出身はどこなの？」
Takeru: “I am from Hokkaido.” → 「北海道（ほっかいどう）出身だよ。」
Even though Japan is a very small country it is pretty diverse. In Hokkaido it is very cold and a lot of snow falls during the winter. In contrast, Okinawa is much more hot and it is usually sunny all the time. Therefore, not only the culture but how the people look differs a lot between people from different regions.
I recommend you to visit many different places other than famous prefectures in Kansai (Osaka, Kyoto, Hyogo) and in Kanto (Tokyo, Kanagawa) because it has many other things you can enjoy.
Hokkaido’s got the best seafood, Kyushu has many onsens to have a relaxing trip, Fukuoka has the best ramen, and by going to Okinawa you can embrace the small islands with distinct cultures.