This should be titled: "Ying's Yang"
"A quirky Kung Fu master reluctantly befriends a young prostitute and re-discovers his passion for the martial arts.
Ying has long given up the martial arts, preferring to waste away his days on beer and dubious night life. But when a young prostitute befriends him and entices him to teach her the hidden ways of the martial arts, he gets more than he bargained for. Deep in the Asian mafia underground, a longstanding feud between rival gangs re-ignites and Ying is forced to confront his fears and arch nemesis in battle."