Looking for a Title

Looking for a shoujo that's part of a series of oneshots. There's a popular guy and one day this tomboy girl comes in the classroom and hits him because she heard he messed with another girl's feelings. Turns out the other girl was lying but the popular guy starts to be interested in the tomboy girl and falls in love with her. She's in the same judo team or something as another one of his friends and there's a part where they're buying chocolates together for valentine's day.