In combinatorial game theory, a game is partizan if it is not impartial. That means some play in the game is available to one of the two players and not to the other.

Most games played with pieces are partizan: it is usual to have pieces that 'belong' to one side, so that one player only can move them. The extension of the theory to partizan games also allows the significance of numbers as games to be seen, in a way that is not possible with impartial games alone.