Semi-related... I'll be in HKG for several days later this year, and was thinking about doing a day tripper to Shenzhen (a short train ride away, but in mainland China).
Is the only option for a US citizen a full blown visa? I've gotten Chinese tourist visas before, but I don't have a current one, and would rather not go through the trouble and expense ($130) for this one time use for under a day.