Follow the Tokaido railway west from Tokyo to Kyoto, then finish in Osaka. Split six hotel nights evenly between the three cities. Arrival and departure use days one and seven, with transfers on days three and five: you get three full sightseeing days and extra time around the train rides.
The route’s longest Tokyo day covers Asakusa, Kappabashi’s kitchenware shops and Ueno’s museums. If Shibuya’s shopping is your priority, replace that day with Shibuya and Harajuku while keeping two nights in Tokyo.
Kyoto’s full day combines Fushimi Inari and eastern streets, followed by Arashiyama the next morning. Osaka gives you two evenings and a day for the castle, river and shops, with dinner in the city where you sleep each night. Choose ten days for an overnight hot-spring stay in Hakone, or add Tokyo nights for shopping and contemporary art.