How to win at Tic Tac Toe: 7 strategies that actually work
Against a perfect opponent nobody wins Tic Tac Toe. Against a real person, you can win a lot. These seven habits turn random games into wins.
Tic Tac Toe has a reputation for being "solved", and it is: if both players make no mistakes, every game ends in a draw. But people make mistakes all the time, especially in the first three or four moves. Winning is about steering the game into positions where the natural-looking move is the wrong one, and then punishing it.
A quick vocabulary note: the board has four corners, four edges (the middle square of each side) and one centre. Those three kinds of square behave very differently.
1. Always check for a win, then for a block
It sounds obvious, but most lost games are lost here. Before every move, ask two questions in this order:
- Do I have two in a line with the third square empty? Play there and win.
- Does my opponent? Play there and block.
Only when the answer to both is "no" should you think about anything clever. Players who are excited about a plan often miss a simple win on the board, or miss that their opponent is one move from three in a row.
2. Open in a corner when you go first
The corner is the most dangerous opening in practice. If you play a corner, your opponent has exactly one safe reply, the centre. Every other square loses by force. Compare that with opening in the centre, where four of the eight replies are safe.
Beginners often answer a corner with the opposite corner or an adjacent edge, and from there you can force a win. You can read the full comparison in the best first move in Tic Tac Toe.
3. If they don't take the centre, take the opposite corner
Say you open in the top-left corner and your opponent answers on an edge or another corner. Your strongest follow-up is usually another corner. You now control two corners, and the centre and a third corner are both available to you. That is the shape that creates a fork.
In the second diagram, X threatens to complete the left column. O has to block on the middle-left. Then X plays the bottom-right corner, threatening both the bottom row and the diagonal through the centre. O can only block one.
4. Build forks: two threats at once
A fork is a move that creates two different lines of two at the same time. Your opponent can only block one of them, so you win next turn. Almost every win against a careful player comes from a fork.
The easiest forks to set up use corners, because each corner sits on three lines (a row, a column and a diagonal), while an edge square sits on only two. We cover the common fork patterns, and how to defend against them, in Tic Tac Toe forks and traps.
5. As the second player, know the one trap that catches people
Here is a position that wins a surprising number of games for X. X opens in a corner, O correctly takes the centre, and X takes the opposite corner.
It feels natural for O to grab another corner. That is a mistake: X then takes the last free corner and forks. O must play an edge here. When you are X, set this up and see how often it works. When you are O, remember it.
6. Make your opponent move where you want
A two-in-a-row threat is not only a way to win. It is also a way to force your opponent's next move, because they have to block. Strong players use threats to push the opponent onto squares that do nothing for them, while the threatening player's own marks keep building toward a fork.
Before you make a threat, look at the square your opponent will be forced to play. If blocking there gives them two in a row, your threat has backfired. If it gives them nothing, your threat gained you a free move.
7. Practise against an opponent that never gets tired
The patterns above become automatic with repetition. Playing a computer is a fast way to get that repetition:
- On an easy opponent that plays randomly, practise setting up forks from every opening.
- On a medium opponent that blocks your immediate threats, you can only win with real forks, which is exactly the skill you want.
- On a perfect opponent, the goal flips: never lose. If you draw every game against it, your defence is sound.
We wrote a level-by-level plan in how to beat the computer at Tic Tac Toe.
A quick checklist
Every turn: win if you can, block if you must, fork if it's there, stop their fork, then prefer the centre, then a corner, then an edge.
That priority list is close to how a perfect player thinks, and it is the foundation of never losing at Tic Tac Toe. Learn it, and you will win every game your opponent gives you a chance to win.