Hello: I am a US citizen living in Japan. I will be passing through Shanghai (not changing airport but transiting at the same airport) and I have a long 12 lay over. I would like to make a quick trip to Shanghai downtown for fun. I heard that if you are in Shanghai for less than 48 hours and have a return ticket, you can get free visa on arrival. Is that true? Please let me know what I need to do for this, if anything.