In combinatorial game theory, a game is partisan or partizan if it is not impartial. That is, some moves are available to one player and not to the other.
Most games are partisan; for example, in chess, only one player can move the white pieces.
Partisan games are more difficult to analyze than impartial games, as the Sprague–Grundy theorem does not apply. However, the application of combinatorial game theory to partisan games allows the significance of numbers as games to be seen, in a way that is not possible with impartial games.