How to Never Lose at Tic-Tac-Toe

If You Are Going First

• 1

  Place your first mark in the center.

• 2

  If your opponent places her first mark in a corner, place your second mark in one of the two corners nearest her mark. (Otherwise, place your second mark in one of the two side squares diagonal to hers to set yourself up for a win in one to two moves.)

• 3

  If your opponent places her second mark in the other of the two corners nearest her first mark, place your third mark between her two marks, then keep blocking your opponent to force a draw. (Otherwise, place your third mark in a row to win.)

If You Are Going Second

• 4

  If your opponent places her first mark in the center, place your first mark in a corner. (Otherwise, place your first mark in the center, then keep blocking your opponent to force a draw.)

• 5

  If your opponent places her second mark in a corner, keep blocking your opponent to force a draw.

• 6

  If your opponent places her second mark on a side, keep blocking your opponent to force a draw.