Jiangnan (literally "south of the Yangtze") is the canal-rich region of eastern China. The Shanghai-Suzhou-Hangzhou circuit is the classic way to experience it — 5 relaxed days, with high-speed trains of just 30-60 minutes between each city.
Days 1-2, Shanghai: the Bund’s colonial architecture facing the Pudong skyline, the old town of Yuyuan Garden and City God Temple, and a night river cruise.
Day 3, Suzhou: 30 minutes by train. Visit the Humble Administrator's Garden (one of China's four great gardens), stroll the Pingjiang Road canal district, listen to a Pingtan ballad, and try Su-style noodles.
Days 4-5, Hangzhou: one hour by train. Cycle or boat around West Lake, climb Leifeng Pagoda for the panorama, and finish with a cup of Longjing tea at the village that grows it.
This route works all year; spring and autumn are the loveliest. Book high-speed rail tickets on the official 12306 app and hotels early in peak season.