, the strategies that students found were often dependent on some particular moves by the opponent, if the opponent made a different move, the strategy that ensures victory is possible (the only criterion being whether the player should start first). This is a sure-win strategy. But in tic-tac-toe, there are no sure-win strategies; a winning strategy in simply one that will maximize the chance of a player winning. This will be my definition of a winning strategy. Some winning strategies for tic-tac-toe follow.