Originally Posted by Loren Pechtel

As you say, no dual citizenship. However, what that means is that if you acquired another citizenship China considers you to have given up your Chinese citizenship.

My wife has birthplace: "Shanghai". In practice that translates to her having to provide evidence that she doesn't pretend to be a Chinese citizen. Turn in your Chinese passport, or show a previous Chinese visa, I don't know what else meets their requirements. In practice that translates to her sending her old passport along when getting the first visa in a new passport.