The Duke of Mount Deer (1984)

It is the early years of the Manchu (Qing) empire and the new Emperor (Andy Lau) needs all the help he can get from Tony Leung. Tony plays a double-dealing rogue who is never quite sure whose side he is really on, the Manchu emperor, or the Ming loyalists who want China to be ruled by the Chinese. Literal English title is "The Duke of Mountain Deer".