Can the 72 hour visa exemption be used by US citizens for tourism in the greater Beijing area.

My husband, a friend and I are taking a cruise in 2014 that disembarks in Tokyo. We are all U.S. citizens with passports that will have greater than 6 months remaining at the time of travel. We would like to fly from Tokyo to Beijing via China Eastern Airlines, and spend no more than 72 hours touring the greater Beijing area (Forbidden City, Great Wall, etc). Can we utilize the 72 hour exemption for this purpose, or do we need to apply for it to China.