The Japanese version is actually the original version. It's good. I just preferred the Korean version. There's some differences with the storytelling. I recommend you watch both. One of the best dramas I've seen.
Both Deal with Evil teachers that just rub you the wrong way. Both female leads have rich parents who try to make them what they want to be. They have to deal with the Evil Teacher picking on only them. Both leads and her friends help mend relationships between students. In addition, try to find out why their teacher is like that. If you like this drama the Queens classroom gives you the same amount of feels.