How to beat the computer at Tic Tac Toe
Tic Tac Toe is a solved game: if both players play perfectly, it is always a draw. So you cannot force a win against a perfect player, but you can make sure you never lose, and you can punish every mistake.
Here is the strategy, in the order of the moves.
If you go first
Take a corner. It gives you the most chances because a corner is part of three winning lines, while an edge is part of only two and the centre is part of four.
If your opponent replies in the centre, take the opposite corner. If they reply anywhere else, you can build towards a fork.
If you go second
If the first player takes a corner, take the centre. Anything else lets them force a win. If they take the centre, take a corner. Then block every line they threaten.
Make a fork
A fork is a move that creates two ways to win at once, so your opponent can only block one. For example, if you hold two opposite corners and the centre is the opponent's, taking a third corner makes two lines at once, each with an empty square to finish it. Look for the move that makes two lines of two at the same time.
Block a fork before it happens
If your opponent can make a fork next turn, stop it now. You can do that by taking the fork square yourself, or by forcing them to respond to a threat of your own that does not help them.
The priority order
On every turn work down this list and play the first one that applies:
- Win if you can complete three in a row.
- Block if they can complete three in a row.
- Make a fork.
- Block their fork.
- Take the centre.
- Take the opposite corner to theirs.
- Take any empty corner, then any edge.
Frequently asked questions
Can you always win at Tic Tac Toe if you go first?
No. If the second player plays correctly, the game is a draw. You can only win if the other player makes a mistake.
What is the best first move in Tic Tac Toe?
A corner. It gives the opponent the most chances to go wrong, because only one reply, the centre, avoids losing.
What is a fork in Tic Tac Toe?
A move that creates two threats to win at the same time. The opponent can block only one.
How do I beat the computer at Tic Tac Toe?
The lower levels make mistakes, so use the priority list above and look for forks. The top levels play without mistakes, so a draw is a good result against them.
Put it into practice
Start against Trevor, the friendliest opponent, and work your way up the ladder of ten computer players to Pete, the hardest. It’s free and works in your browser.
Play Tic Tac Toe now