Japan administrative divisions are called todofuken (prefectures), which sounds complicated but actually splits into just 4 types: 1 to (Tokyo), 1 do (Hokkaido), 2 fu (Kyoto and Osaka), and 43 ken, for 47 in total. Why the different labels? Historical baggage — during the Edo era, fu marked political strongholds (Kyoto-fu, Osaka-fu), ken became the post-reform general administrative units, to is reserved for the capital, and do covers Hokkaido due to its sheer size.
Memorizing all 47 is pointless for tourists; remembering the top 10 is enough. Below are the TOP 10 most-visited and best-value picks for Chinese, Taiwanese, and English-speaking tourists.
1. Tokyo (14 million) The capital. Shinjuku, Shibuya, Asakusa, Ginza, Akihabara, Odaiba — no explanation needed. Must-visit: Tokyo Skytree, Meiji Shrine, Tsukiji Outer Market, Ueno Park, Tokyo Disney. Best season: spring cherry blossoms (late March to early April), autumn foliage (late November).
2. Kyoto (2.55 million) The top pick for ancient capitals. Must-visit: Kiyomizu-dera, Fushimi Inari, Kinkaku-ji, Ginkaku-ji, Arashiyama, Gion, Nijo Castle, Byodo-in. Best season: spring cherry blossoms (Philosopher Path), autumn foliage (mid-November to early December, Tofuku-ji), winter snow (Kinkaku-ji in snow is gorgeous).
3. Osaka (8.8 million) Eating, shopping, plus Universal Studios. Must-visit: Dotonbori, Shinsaibashi, Osaka Castle, Shinsekai, Kuromon Market, USJ. Osaka is the West Japan transit hub and works as a Kansai base. Best season: any time of year, though midsummer (July-August) is muggy and best avoided.
4. Nara (1.32 million) An ancient capital older than Kyoto (became capital in 710). Must-visit: Todai-ji (Great Buddha plus deer), Kasuga Taisha, Kofuku-ji, Nara Park. Deer roaming the streets are pure therapy. 45 min by JR from Kyoto. Best as a day trip.
5. Hokkaido (5.41 million) Summer cool, winter skiing. Must-visit: Sapporo, Otaru, Hakodate, Furano (summer lavender), Niseko (winter skiing), Shiretoko (wildlife). Winter is most popular but travel costs run 50% higher. Best season: June-August summer, December-March winter snow.
6. Okinawa (1.46 million) Japan only subtropical island chain. Must-visit: Naha, Shuri Castle, Churaumi Aquarium, Ishigaki Island, Miyako Island. Like Japan Hawaii, with crystal-clear water. Best season: April-June and September-November (avoid typhoons plus summer break crowds).
7. Kanagawa (9.23 million) A satellite prefecture next to Tokyo, but strongly independent. Must-visit: Yokohama (Chinatown plus Minato Mirai), Kamakura (ancient capital plus Great Buddha plus Enoshima), Hakone (hot springs plus Mount Fuji views). Doable as a day trip from Tokyo.
8. Hiroshima (2.77 million) Historically heavyweight sights plus great food. Must-visit: Peace Memorial Park plus the Atomic Bomb Dome (World Heritage), Miyajima Itsukushima Shrine (the torii in the sea), Hiroshima-yaki (different from Osaka-yaki). 1 hr 20 min from Osaka by Shinkansen.
9. Nagano (2.02 million) The Japanese Alps plus snow monkeys plus old castles. Must-visit: Matsumoto Castle (one of 5 surviving national-treasure castles), Jigokudani snow monkeys (monkeys bathing in hot springs), Hakuba ski resorts, Kamikochi. Best season: winter snow and summer cool.
10. Gifu (1.99 million) Home to the Shirakawa-go World Heritage Site. Must-visit: Shirakawa-go (most beautiful in snow season), Takayama old streets (a "Little Kyoto"), Gero Onsen (one of Japan three great hot springs). 2 hours from Nagoya. Shirakawa-go illuminations in winter are a Japanese postcard scene.
Next wave worth considering: 11. Fukuoka (Kyushu capital plus ramen), 12. Hyogo (Kobe plus Himeji Castle plus Kinosaki Onsen), 13. Shizuoka (Mount Fuji plus tea plus eel), 14. Kumamoto (Kumamoto Castle plus Mount Aso), 15. Aichi (Nagoya plus Nagoya Castle).
How to use this ranking 5 days: 1+3+4 (Tokyo plus Osaka plus a day in Nara) 7 days: 1+2+3+4 (Tokyo plus Kyoto plus Osaka plus Nara) 10 days: 1+2+3+4+9 (add Nagano) or 1+2+3+4+5 (add Hokkaido) 12-plus days: 1+2+3+4+7+8 (add Hakone plus Hiroshima)
For your next trip, match this list against your day count and avoid the "want to visit lots of prefectures" trap — losing half your itinerary to travel time is painful. Less, but better is the truth of independent travel in Japan.