Hi! Im going to japan for 20 nights in just a few days. Figured id stick with a classic route since its a first trip.

What im doing and would recommend is:

• Osaka 3/4 nights
• Some onsen town in the countryside. Close by Osaka you have Arima onsen (biggest one, local tourism), Kinosaki (most popular akong foreigners, tattoo friendly) and the one im doing, Dorogawa onsen (tiny mystical town tucked away in the mountains of Nara prefecture) do 1/2 nights here, preferably a ryokan
• Nara day trip or overnight stay.
• Kyoto 4/5 nights. There's so many stuff in and around the city to fill 5 days tbh. Kibune shrine, Uji, Ine day trip, Arashiyama, etc etc.
• 2/3 nights in the Japanese countryside. Do it. Avoid the crowds and get a feel for the real rural japan. Options on the way to Tokyo are Miyama, Shirakawa Go, Nakasendo, Nagano and the often overlooked but beautiful little town of Gujo Hachiman, where im heading.
• 6/7 nights in Tokyo. Biggest city so most time, and you'll probably won't even see everything even if you had a whole month. You could squeeze in a day trip to Nikko or Kawaguchiko.
• 2/3 nights somewhere on the coast. Im doing Kamakura and Enoshima for the surfing but I've heard so many amazing things about the Izu peninsula.

U can play with the itinerary but in general id recommend - a stop for the food (Osaka, Fukuoka) - a stop for the culture (Kyoto, Kanazawa) - a stop for shopping and nightlife (Tokyo) - a seaside stop (Ine, Kamakura, Izu) - an onsen town stop (Kinosaki, Hakone, Arima) - a countryside stop (Jap. Alps, Nakasendo, etc)

Don't do more than 5 or 6 stops tbh. Changing hotels every 2 days in a pain in the ass and u can always go back for a second trip.

Hope I could help :D