Technically to teach in China you are meant to have a Z visa, applied for outside of the country at your nearest Chinese consulate (or transferred within if already in china). Then when you get to China your employer converts this into a Residence permit and also gives you a red book known as a Foreign Expert’s Certificate.

However there are other ways that are technially illegal. Most schools in Changchun operate by asking you to come to China on a 3 month L tourist visa. You are not allowed to work on such a visa it is meant for travel only. What lots of employers do is to use ‘connections’ to convert the L into a business F visa.  Your dodgy employer will refer to this simply as a ‘work visa’ but the fact is that it is specifically excluded from allowing people to teach. You can’t convert a L into a Z visa. (Actually, in Changchun you still can do this if you are working for someone with enough clout at the PSB!)Changchun is very lax on the national requirements for being able to obtain visas – basically anything is possible as long as you have the correct contacts. You may or may not need a medical.
Visas are easily obtainable in the city from the corrupt cops/mafia (they are one and the same in Changchun) at the Renmin Guangchang PSB station （人民广场公安居）, but it will cost you anything from 1200-2500元 depending upon whom you ask.
I think at least 80% of the teachers in this city are working under F visas; so It goes on – but this doesn’t mean YOU won’t get in trouble!!
This situation exists as it is notoriously difficult for a company/school to get the correct licences required to hire foreign workers. It costs a lot of money and guanxi to get such licences and so a market has developed whereby F visas are used instead. An F visa resident permit is essentially identical in appearence to a Z visa residence permit, however those with an F visa RP won’t have the little red coloured Foreign Experts Certificate. Instead they will have a little brown coloured book that says something like Alien Work Permit on the front cover. Legally you can’t teach on a brown book. You can lecture or consult (or do any other job for that matter) but teaching is for those with the red Foreign Experts Certificate only. However the police usually turn a blind eye – but it’s a risky game to get involved in and could get you in a heap of trouble.

And so, there are several recruiting companies operating in Changchun – that do have the right to hire foreigners legally- that have an almost monopolistic postion in the private sector. They have serious connections and are effectively run by the police responsible for issuing visas. They are cut-throat operators and should be avoided.