Tic-tac-toe is a solved game, which means if you follow a few simple rules in the right order you will never lose, full stop. The worst you can do with perfect play is a draw, and against anyone who slips up you will win. Here is the exact priority list I use, the same one a computer follows, so you can play unbeatable tic-tac-toe every time.
What I cover
1. The unbeatable priority list
On every single turn, run down this list and play the first move that applies. This order is the whole strategy, and it never changes.
- Win. If you have two in a row with the third square open, complete it and win immediately.
- Block. If your opponent has two in a row with the third square open, block it.
- Fork. If you can create a position with two ways to win at once, do it. Your opponent can only block one.
- Block a fork. If your opponent threatens a fork, stop it, either by blocking directly or by forcing them to defend a two-in-a-row of yours instead.
- Center. Take the center square if it is free.
- Opposite corner. If your opponent is in a corner, take the corner diagonally opposite.
- Empty corner. Take any free corner.
- Empty side. Take any free edge square as a last resort.
Follow this exactly and a loss is mathematically impossible. Every move below is just an application of these eight rules.
2. Going first: open in a corner
When I move first, I open in a corner, not the center. A corner opening is the strongest start because it gives your opponent the most ways to go wrong. The only reply that draws for them is taking the center, and most casual players do not know that, so they grab a corner or a side and walk straight into a fork.
After my corner opening, if they answer anywhere except the center, I can almost always set up two simultaneous threats within a couple of moves and force a win. If they do find the center, I stay calm, keep following the priority list, and settle for the guaranteed draw.
3. Going second: take the center
When I move second, my single most important job is to take the center the moment it is free. The center sits on four of the eight possible winning lines, more than any other square, so owning it shuts down the majority of your opponent's plans at once.
If the first player opened in a corner and I take the center, I am safe: from there I just block their threats and look for a fork of my own, and the game draws at worst. The classic trap to avoid is letting the first player hold two opposite corners while I sit on a side, because that hands them a fork. Taking the center first removes that danger entirely.
4. Creating and blocking forks
A fork is the move that actually wins games of tic-tac-toe. It is a single move that creates two separate two-in-a-row threats at the same time. Your opponent can only block one of them, so on your next turn you complete the other and win.
Building your own fork
Forks come naturally from holding corners. If I have two corners on the same side of the board with the center empty between the relevant lines, my next corner or center play often opens two threats at once. I am always scanning for a move that touches two of my own near-complete lines rather than just one.
Stopping their fork
Blocking a fork is trickier than blocking a simple line, because you cannot always cover both future threats directly. The reliable trick is to go on the offensive: make your own two-in-a-row that forces them to block, as long as that block does not hand them the fork. By forcing their hand, you use up their move and dismantle the fork before it forms. If no such forcing move exists, occupy the square they need for the fork itself.
5. Putting it into practice
The reason this works is that tic-tac-toe has so few possible games that perfect play is fully mapped. There is no luck and no hidden information, so a player who never breaks the priority list simply cannot be beaten. The only skill is discipline: checking for a win, then a block, then a fork, in that order, on every turn without rushing.
Once the rules are second nature, the real fun is watching an opponent who does not know them fall into the corner trap again and again. The best practice is fast repetition against the computer, where you can test openings and see how each reply plays out. Try it head to head on our free tic-tac-toe game and run the priority list on every move until it is automatic.
FAQ
Can you really never lose at tic-tac-toe?
Yes. With perfect play the game is a forced draw, so the worst outcome you can ever face is a tie. You only lose by breaking the priority list, usually by missing a block or a fork.
Is it better to go first or second?
Going first is a small advantage because you can open in a corner and set traps. Going second is perfectly safe too, as long as you immediately take the center.
What is a fork in tic-tac-toe?
A fork is one move that creates two winning threats at once. Since your opponent can only block one, you win on the following turn. Creating forks is how you turn a draw into a win.