How to never lose at tic tac toe: strategy guide

You never lose at tic tac toe by answering the opening correctly and then following a fixed priority list: win if you can, block if you must, and never let your opponent create two threats at once. Do that every move and the worst result you can get is a draw, because tic tac toe is a solved game and perfect play by both sides always ends level.

Is tic tac toe always a draw?

Between two players who make no mistakes, yes. Every opening move by X can be answered, so neither side can force a win. This has been checked across every possible game.

Real games are still won, because one player makes a bad reply early and the other knows how to punish it. Never losing means not making that reply.

Throughout this post the squares are numbered from the top left:

 1 | 2 | 3
---+---+---
 4 | 5 | 6
---+---+---
 7 | 8 | 9

Square 5 is the centre. Squares 1, 3, 7 and 9 are corners. Squares 2, 4, 6 and 8 are edges.

Why the centre and corners matter

There are eight lines on the board: three rows, three columns and two diagonals. Not every square sits on the same number of them.

The centre sits on four lines.
Each corner sits on three lines.
Each edge sits on two lines.

A square on more lines takes part in more threats and blocks more of your opponent’s. Edges are the weakest squares, and most losing moves are edge moves played at the wrong moment.

Forks: how tic tac toe games are actually won

A threat is two of your marks in a line with the third square empty. Your opponent can block one threat per turn. A fork is a move that creates two threats at the same time. They block one, you complete the other.

Almost every won game ends in a fork, because a single threat is simply blocked. The real game is creating forks for yourself and denying them to your opponent before they appear.

Here is what a fork looks like. X has just played square 7:

 X | . | O
---+---+---
 . | O | .
---+---+---
 X | . | X

X now threatens to complete the left column (needs square 4) and the bottom row (needs square 8). O can block only one. X wins next turn.

How to win tic tac toe as X

X moves first. Use that to give your opponent as many ways to go wrong as possible.

Open in a corner. After a corner opening, O has exactly one reply that holds the draw: the centre. Every other reply, edge or corner, loses against correct play.

The centre is also safe. After a centre opening, O must take a corner. Any edge reply loses. That is fewer traps than the corner opening sets, but it is still a perfectly sound first move.

The edge opening does not lose either, but it gives O the most comfortable choices of the three, so there is little reason to play it.

Punishing an edge reply to a corner

Say you open in square 1 and O answers on the edge at square 2. Take the centre:

 X | O | .
---+---+---
 . | X | .
---+---+---
 . | . | .

You now threaten the diagonal through 1, 5 and 9, so O is forced to block at square 9. Then play square 7:

 X | O | .
---+---+---
 . | X | .
---+---+---
 X | . | O

That is a fork. You threaten the left column (square 4) and the other diagonal (square 3). O cannot block both.

An edge reply to the centre loses the same way: X takes a corner, forces a block in the opposite corner, and then forks from a third corner.

How to never lose at tic tac toe as O

Playing second is about surviving the first two moves. After that, the priority list below keeps you safe.

If X opens in a corner, take the centre. This is the only reply that does not lose, and the one most people get wrong.

If X opens in the centre, take a corner. An edge reply loses, as shown above. A corner reply holds the draw.

If X opens on an edge, taking the centre is the simplest safe answer.

The opposite-corner trap

This catches players who already know to take the centre. X opens in a corner, O correctly takes the centre, and X takes the opposite corner:

 X | . | .
---+---+---
 . | O | .
---+---+---
 . | . | X

It looks natural for O to grab another corner. It loses. Say O plays square 3. That threatens the 3-5-7 diagonal, so X blocks at square 7, and the block is itself a fork: X now threatens the left column (square 4) and the bottom row (square 8).

 X | . | O
---+---+---
 . | O | .
---+---+---
 X | . | X

The correct move for O is an edge. Playing square 2, for example, makes a threat down the middle column. X has to block at square 8, and O is no longer facing a fork. Play continues to a draw.

There is a mirror-image version for O after a centre opening. If X plays the centre, O takes a corner, and X takes the corner opposite O’s, then O must take another corner. An edge reply there lets X block and fork in one move.

The priority list: tic tac toe strategy in eight rules

In 1972 Allen Newell and Herbert Simon published a simple rule set for tic tac toe. On each turn, take the first rule that applies:

Win. If you have two in a line with the third square empty, complete it.
Block. If your opponent has two in a line, take the third square.
Fork. Make a move that creates two threats at once.
Block a fork. If your opponent could fork next turn, stop it.
Centre. Take the centre if it is free.
Opposite corner. If your opponent holds a corner, take the one diagonally opposite.
Empty corner. Take any free corner.
Empty edge. Take any free edge.

The order matters. Winning beats blocking, and blocking beats forking, because a fork is worth nothing once their line is complete.

Rule 4 is the subtle one, and the opposite-corner trap is exactly where it gets tested. When your opponent has two possible fork squares, simply taking one of them often fails, because they take the other. The better way to block is to make a threat of your own that forces them to answer somewhere harmless, as long as their forced reply does not itself create a fork. That is why O plays an edge in the trap above: the edge makes a threat whose forced answer is safe, while the corner makes a threat whose forced answer is a fork.

Follow these eight rules on every move and you will not lose a game of tic tac toe. Against an opponent who also follows them, every game will be drawn.

What if a game couldn’t end in a draw?

Once both players know the rules above, tic tac toe stops being a contest. The outcome is decided before the first move.

overload is our attempt to keep the board and remove the guaranteed draw. It is a free tic tac toe variant on onedge, played in the browser against a bot or a friend.

The rules, briefly:

The board is the same 3x3 grid. Against the bot you play X and move first.
Instead of identical marks, each player has one each of the numbers 1 to 9, to spend over the whole match.
On your turn you pick an unspent number and place it on an empty square, or on a square holding a lower number. That bumps the lower number off the board for good, and the square is now yours.
Three in a row wins, judged on who holds each square now.
If neither player can move and nobody has a line, the match is not thrown away. It goes to whoever holds the highest-value line, adding up the numbers on their best line. If that ties, it falls back to total value held, then number of squares held, then who holds the centre.

A genuine draw needs all four of those measures to come out identical, so in practice matches almost never end level. The full rules and scoring are in the how to play overload guide.

What carries over from classic tic tac toe

Square values. The board has the same eight lines, so the centre still sits on four, corners on three and edges on two. The centre is still the most valuable square, which is why the usual advice is to open there with a middling number such as a 5 or 6 rather than your 9.

Forks. Two threats at once is still the strongest thing you can make. Most overload matches still end with three in a row, and a fork is still the most reliable way to get one.

Win before block. If you can complete a line this turn, do it. Nothing your opponent was threatening matters once the match is over.

What does not carry over

No square is permanent. In classic tic tac toe a block is forever. In overload a block is only as safe as the number you used. If your opponent still holds a higher number, your block can be taken back. A 9 on the board can never be bumped, but every lower number can, until the numbers that could take it have been spent.

Forks can be broken. A classic fork is final because the only answer is to block one empty square. In overload your opponent has another answer: bump the square the two threats share. A fork resting on a 3 is much weaker than one resting on a 7.

The opening book is gone. “Answer a corner with the centre” assumes the centre stays put. Here the centre changes hands whenever someone spends a bigger number on it, so there is no fixed list of losing replies to learn.

Your hand is part of the board. Both hands are visible at all times. A high number you have not spent threatens every square, and once it is spent it threatens nothing further. Counting your opponent’s remaining numbers matters as much as reading the grid.

More games that reward thinking a move ahead are on the strategy games page.

Frequently asked

How do you never lose at tic tac toe? Answer the opening correctly, then follow a fixed order every move: win if you can, block if you must, make a fork, stop their fork, then prefer the centre, the opposite corner, any corner, and finally an edge. Played consistently, that guarantees at least a draw.

Is tic tac toe always a draw? With perfect play by both sides, yes. Neither player can force a win. Real games are decided when one player makes a losing reply, most often by not taking the centre after a corner opening, or by taking an edge after a centre opening.

What is the best first move in tic tac toe? A corner. It leaves the second player only one reply that does not lose, the centre. The centre is also a safe opening, but it sets fewer traps. Neither move can force a win against an opponent who answers correctly.

Is there a tic tac toe with no draws? overload comes close. Every square can be taken back by a higher number, and a match with no three in a row is settled on line value, total value, squares held and the centre, in that order. A genuine draw needs all four to tie, which almost never happens.

Does classic tic tac toe strategy work in overload? Partly. The value of the centre and the power of forks carry over. The fixed opening replies do not, because no square is permanent, and you have to track your opponent’s unspent numbers as closely as the board.

Play overload