I'm looking for a movie.?

I think it's Japanese. It's about a new girl in school and a plain guy
who falls in love with her. The girl was the ex(?) of a gang member,
and so the gang goes to look for her. I think that's the reason why
she changed schools. Anyway, the guy goes to save her, and there was a
billiards scene, I think. I just happened to watch it briefly on
YouTube before, and I forgot the title.

Please help me. :<