China will tax world-wide income for non-citizens if they spend 5 contiguous years in China. I recently had my month out (ok, it was more than a year ago) to avoid this situation.
The $100k floor only applies to work done outside of the US. If you work for an American company, you'll invariably go on business trips back home, which mess up your taxes substantially as this isn't covered on the US/China tax treaty.
The $100k floor only applies to work done outside of the US. If you work for an American company, you'll invariably go on business trips back home, which mess up your taxes substantially as this isn't covered on the US/China tax treaty.