Do I need a visa for the following trip of 72 hours to Shanghai?

I fly from the USA to Osaka on Sept. 17. I then go from Osaka to Shanghai on Sept. 22. I return to Osaka on Sept. 25 and return to the USA on Oct. 1. My flight arrives at Pudong at 2:35 p.m.on Monday; my flight from Pudong is at 8:55 a.m. on Thursday.