US Passport Holder Applying for Expedited Visa while in Japan

Hello. I am a US citizen living in New York, leaving for Tokyo in two days on Sunday May 18,2014. I have a ticket to Shanghai on ANA for Thursday, May 22 and returning to Tokyo on Monday, May 26 before returning to New York. I spent yesterday and this morning at the Chinese Embassy here in New York trying to expedite the processing, but they said I should apply once in Japan. As I arrive in Japan in the evening, the earliest I will be able to go to the Chinese Embassy in Tokyo will be Tuesday morning, May 20. My flight to Shnaghai is on Thursday, May 22 at 14:00. Is it possible to get it expedited in that time frame?