Robust game play against unknown opponents

A standard assumption of search in two-player games is that the opponent has the same evaluation function or utility for possible game outcomes. While some work has been done to try to better exploit weak opponents, it has only been a minor component of high-performance game playing programs such as Chinook or Deep Blue. However, we demonstrate that in games with more than two players, opponent modeling is a necessary component for ensuring high-quality play against unknown opponents. Thus, we propose a new algorithm, soft-maxn, which can help accommodate differences in opponent styles. Finally, we show an inference mechanism that can be used with soft-maxn to infer the playing style of our opponents.