thanks for your informed response linguisticus. Would you advise me to proceed with caution, or refuse the offer without a contract and z-visa prior to arrival in china. I am sure you can't tell me definitively what to do, but I am really at a loss. My girlfriend and I both have a masters degree and some teaching experience, and he sound sincere enough. The semester doesn't start until February, but he says that our accommodations are ready so we can come over early if we like. He also sent us a copy of the contract that we would sign upon arrival. But another point of concern (esp. considering your warning) is that he volunteered the following information after we had already accepted the offer:

"By now, there are 5 applicants for the two positions. But I prefer to have you both because you are partners and you are from the same university."

One last thing. I would like to ask you since you have 3 years experience in shenzhen. We were offered 8000 with accommodation+bonus. Is this fair given our degrees and experience?

Thank you so much for your help!