Can you always win at tic tac toe?

No. Tic tac toe is a solved game: if both players play perfectly, every game ends in a draw. You can guarantee never to lose, and you can win whenever your opponent makes a mistake, but you cannot force a win against correct play.

What is the best first move in tic tac toe?

There are only three openings that matter: centre, corner or edge. The centre sits on four of the eight winning lines, which makes it the strongest single square. A corner is the better practical choice against a human, because it leaves your opponent exactly one correct reply — the centre — and every other reply loses.

What is a fork in tic tac toe?

A fork is one move that creates two threats at once. Your opponent can only block one of them, so the other wins on your next turn. Every win between competent players comes from a fork.

How many possible tic tac toe games are there?

255,168 if you count every sequence of moves. Counting only how a finished board can look, ignoring rotations and mirrors, there are 138 terminal positions: 91 won by the first player, 44 by the second, and 3 drawn.

Does a bigger board fix the draw problem?

Partly. A 4x4 or 5x5 board opens far more lines, so forks become easier to build and harder to see coming. Changing what the board does — blocking cells, or requiring four in a row instead of three — reopens the game more effectively than size alone.

Rules and strategy

How to never lose at tic tac toe

Tic tac toe takes a minute to learn and about an afternoon to exhaust. This page covers the rules, the reason two careful players always draw, and the handful of patterns that decide every game that is not a draw.

The rules in thirty seconds
Why perfect play is always a draw
How to never lose
How to actually win: the fork
What a bigger board changes

The rules in thirty seconds

Two players share a three-by-three grid. One plays X, the other O. X moves first, then the players alternate, each claiming one empty square per turn. The first player to line up three of their own marks in a row — horizontally, vertically or diagonally — wins immediately. If all nine squares fill with no such line, the game is a draw.

There are eight winning lines in total: three rows, three columns and two diagonals. That number is worth remembering, because the whole of strategy follows from how those eight lines overlap.

XXX OO

A row wins. So does a column, and either diagonal.

XOX XOO OXX

Nine squares, no line: a draw. Between careful players this is the normal result.

Why perfect play is always a draw

Tic tac toe is a solved game. Every position has been searched to the end, and the conclusion is blunt: if neither player errs, the game is drawn. Going first is an advantage in practice, but not a winning one.

The scale is small enough to be exhausted by hand, given patience. Counting every distinct sequence of moves gives 255,168 games. Counting instead how a finished board can look, and treating rotations and mirrors as the same thing, leaves 138 final positions: 91 won by the first player, 44 by the second, and 3 drawn.

Those numbers explain the appeal and the ceiling at once. The first player wins far more of the possible endings, which is why the game feels winnable — and yet none of those wins can be forced, which is why it stops being interesting once both players know what they are doing.

How to never lose

You cannot force a win, but you can guarantee never to lose. Work down this list every turn and take the first move that applies.

1. WinIf you have two in a line and the third square is free, take it. Nothing else matters.
2. BlockIf your opponent has two in a line, take the third square before they do.
3. ForkMake a move that creates two threats at once. See below.
4. Stop a forkIf they are about to fork you, occupy the square that would do it — or force them to defend by making a threat of your own.
5. CentreIt sits on four of the eight lines, more than any other square.
6. Opposite cornerIf they hold a corner, take the one diagonally across from it.
7. Any empty cornerCorners sit on three lines each. Edges sit on two.
8. Any empty edgeThe last resort, and it usually means the position is already drawn.

Follow that order without exception and no opponent can beat you. It is not an elegant way to play, but it is a complete one.

How to actually win: the fork

Since a win cannot be forced, every win comes from an opponent's mistake — and the mistake is nearly always the same one. A fork is a single move that produces two threats at once. Your opponent blocks one; the other wins.

XO X OX

X holds a diagonal and threatens both open edges. O can only stop one.

XO X

The classic trap: O answered a corner opening on an edge instead of the centre, and is already lost.

The practical version is short enough to memorise. Open in a corner. Your opponent has exactly one reply that saves the game — the centre. Anything else and you can build a fork within two moves. Most people who have not thought about it will answer on an edge, or mirror you in another corner, and both of those lose.

Going second, the defence is just as short: if they open in the centre, take a corner. If they open in a corner, take the centre. Get that one move right and the game is drawn.

What a bigger board changes

The obvious fix for a solved game is more room. A four-by-four grid has far more lines than eight, which makes forks easier to build and much harder to see coming. It helps — but it also slows the game down, and the draw creeps back once players adjust.

Changing what the board does works better than changing its size. Block two squares before the first move and every stored opening is worthless. Require four in a row instead of three and the geometry of a fork changes entirely. Hand out an extra turn for claiming a particular square and the tempo that underpins the whole draw argument stops holding.

That is the idea behind Kit Cat Toe: the same rules you just read, on three board sizes, with five twists that move the goalposts and ten computer opponents who each break them differently. Free on Android, works offline, no account.

Get it on Google Play About the game