Ooooooo! Ok, my pick is "Lady Vengeance" by Chan-wook Park.
If you haven't seen his other films, especially "Oldboy", check those out as well if you like this one. One of my favorite foreign directors. His films "Sympathy for Mr Vengeance", "Oldboy" and "Sympathy for Lady Vengeance" are widely known as the "Vengeance Trilogy".