Is it possible to work at an English academy (hagwon) with an H-1 visa?

Hey! I’m a job seeker coming to Korea next week on an H-1 visa. From what I’ve heard, you’re not allowed to work at a language academy (hagwon) on an H-1, but I actually know a few people who are doing it, so now I’m a bit confused. Can you help clear this up for me?