Re counting fingers and toes, then nose and ..., the number seems to be 34 (including Taiwan).
See: https://en.wikipedia.org/wiki/Provinces_of_China
I've been to all 34 but it took me years and multiple visits. Guidebooks provide the highlights of each, many mentioned here. You'll need to do your own research to narrow down the choices you like and figure out an itinerary that is efficient yet flexible. IMO, six weeks may not be enough time to enjoy each area's flavor and that you'll be constantly on the move. Can you save something for another time?
