How to get a visa for China whilst travelling around the world?

Hi there,

I'll be travelling around the globe for +- 10 months starting the 1st of November 2011 and the plan is to spend at least a month in China around May 2012. It's difficult to get a visa before I leave as they expire within 3 months. So I have to get one during the trip. I'll be in Japan the month before arriving to China. Any tips on how to get a tourist visa from there? And if you have tips for similar situations for countries like Vietnam, Birma/Mynamar or India that would be helpful as well.
Many thanks in advance!
Dimitri