Here's the scoop: They lure new "teachers" to remote areas; because nobody wants to go there, they have to hire what they have, which often is people without the required credentials, and/or people from the wrong countries. Because they can't get the right visa for teachers (the right visa is called Z visa), they disguise the situation in order to accommodate other types of visa, which are illegal for teachers. And there you go: You go underground. There, you are at the mercy of the school because you can't go to the PSB (government authority for foreign teachers) if the school does not pay your full salary, has placed you in a dump apartment, keeps changing your schedule so you have no rest, no time to sleep enough and you become exhausted. And if the authorities barge into your classroom and ask to see your residence permit, you go from underground to jail.