3.3 The reduced strategic form of an extensive game

The strategic form corresponding to an extensive game is given by generating for each player the strategies available to that player.

• A pure strategy specifies a move at each information set of the player.
• A reduced strategy specifies a move for each information set, except for those information sets that are unreachable due to an own earlier move of the same player.

For games with perfect recall, there is a systematic way to generate reduced strategies.