Urgent china visa required

Hey,

Im an australian citizen living in gifu japan under a student visa.

I'm planning a holiday to South Korea and china for the 14th September and leaving from Korea to china on the 20th of September and then returning back to korea on the 24th. Right now I'm not in Japan and will return for Japan on the 11th which leaves me only 3 days to apply and pick up a china visa. (cutting it close??)

I've done some research and people have mentioned in other posts / blogs that it's not possible to get a visa from the Chinese consulate in Nagoya and that I may need to travel to Osaka instead. Does anyone know if this is the case? And if so, would I be able to pay extra to get my visa approved and ready for pick up in 2-3 days?

One more thing, what documents are required?

Your help would be much appreciated!!