Some may disagree with me; however, I don't consider it a good idea to obtain a Z visa before coming to China as Turnoi has advised. Yes you should have the documentation that enables you to get a visa, be it a tourist visa or a business visa. Some business visas, by the way are provided to those who have an expressed interest in teaching and have received a letter of invitation from an academic institution.

The main pitfall of acquiring a Z visa before coming here is that you may find yourself in an untenable situation. You will have already committed yourself to a job that you may find is not suitable for a variety of reasons. Of course no one can stop you from leaving that job if you feel inclined to do so, but by doing so you will be limiting your choices in terms of future employment in China because of the now enforced rule of needing a release letter from your school before getting a position elsewhere.

If you come here on another kind of visa, you'll have the opportunity to check out the school and your accommodations before fully committing yourself. You'll also be able get a feel for the employer and make a determination as to whether or not you really want to work for said individual. Moreover, you may actually find out that your "employer" is really a recruiter, and, if that's the case, you definitely want to slow down and scope things out carefully.

Turnoi's advice is well intentioned, but my perspective is that he has not taught in China for quite awhile, and, therefore, is ill qualified to offer you accurate advice on this matter. Furthermore, don't take my advice to heart either - get as many opinions as you can before making such an important decision. The EFL business here is a money game first and an educational system second. And believe me they play it by their own rules, and they love to lure the greenhorns with the use of various tactics that we would consider unethical but that they consider to be part of the game. Keep that in mind.