Girl disguises herself as a boy, is surrounded by boys, and one of the guys is oblivious to her actual gender and thinks himself to be gay.
Both are historical dramas with some of the best bromance I've seen in dramaland.
Both feature main characters out for revenge and have some interesting swindling scenarios.
Both are martial arts films with Zhang Ziyi in them. They each have really cool action scenes along with an engaging story.
Both are fantasy romance dramas in which a human falls in love with a supernatural character (played by Shin Min Ah in both dramas).