Tic-Tac-Toe

Tic-Tac-Toe is a popular paper-and-pencil game dating back to antiquity. The objective of the game is to make three in a row of either X's or O's. This is demonstrated in the graphic below.

If the first player moves flawlessly, they cannot lose the game. If the second player moves flawlessly, they also cannot lose the game.

Perhaps the strongest opening is the corner. This is the only opening move where the second player only has one response, the middle square, which does not lead to a forced win for the first player.

X | _ | _

_ | O | _

_ | _ | _