  Creating strong agents for games with more than two players is a major open
problem in AI. Common approaches are based on approximating game-theoretic
solution concepts such as Nash equilibrium, which have strong theoretical
guarantees in two-player zero-sum games, but no guarantees in non-zero-sum
games or in games with more than two players. We describe an agent that is able
to defeat a variety of realistic opponents using an exact Nash equilibrium
strategy in a 3-player imperfect-information game. This shows that, despite a
lack of theoretical guarantees, agents based on Nash equilibrium strategies can
be successful in multiplayer games after all.
