The pie rule, sometimes referred to as the swap rule, is a rule used to balance abstract strategy games where a first-move advantage has been demonstrated. After the first move is made in a game that uses the pie rule, the second player must select one of two options:Letting the move stand. The second player remains the second player and moves immediately. Switching places. The second player becomes the first-moving player with the move already done by the opponent, and the opponent plays the first move of their new color.