How to play
Tic Tac Toe
Also known as Noughts and Crosses, XO, Xs and Os, Tick-Tack-Toe
- 1M+ downloads
- On Google Play since 2021
- Free to play
What is Tic Tac Toe?
Tic Tac Toe is a two-player game played on a three-by-three grid. One player marks squares with X, the other with O, and the first to line up three of their own marks wins. It takes seconds to learn, and the whole game fits inside nine squares, which is exactly why the strategy behind it is worth knowing.
How to play Tic Tac Toe
Setting up the board
Draw or open an empty three-by-three grid, giving nine squares in total. Decide who plays X and who plays O; X moves first by convention. Nothing else is needed, and no pieces are ever moved once placed.
The rules, step by step
- Play on a three-by-three grid of nine empty squares.
- X always moves first, then players alternate turns.
- On your turn, place your mark in any one empty square.
- Marks stay where they are; you never move or remove a mark.
- A line of three of your own marks - horizontal, vertical or diagonal - wins immediately.
- If all nine squares are filled with no line of three, the game is a draw.
- Swap who goes first between games so the first-move advantage evens out.
How to win
You win the moment three of your marks form a straight line horizontally, vertically or diagonally - there are eight such lines on the grid. If the board fills with no line completed, the game is a draw, sometimes called a cat's game.
Strategy tips
- Take the centre when you move first. It sits on four of the eight winning lines, more than any other square, so it gives you the most ways to threaten.
- If you move second and the centre is gone, answer in a corner. Against a centre opening, a corner is the only reply that holds the draw.
- Open in a corner when you want to set traps. After a corner opening, the centre is the only square that saves your opponent.
- Build a fork: place a mark that creates two separate two-in-a-rows at once. Your opponent can only block one of them, so the other wins next turn.
- Watch for their forks too. Block one by making a two-in-a-row that forces an immediate answer, or by occupying the square that would complete their double threat.
Origin and history
Three-in-a-row games are ancient: the Romans played a version called terni lapilli, or three pebbles at a time, around the first century BC, in which each player had only three pieces and moved them around a scratched grid rather than adding new ones.
The modern pencil-and-paper form spread in nineteenth-century Britain, where the name noughts and crosses appeared in print in 1858 in the journal Notes and Queries; the American name tick-tack-toe was printed in 1884.
In 1952, Sandy Douglas built OXO, a Noughts and Crosses program for the EDSAC computer at the University of Cambridge, making it one of the earliest known video games.
Frequently asked questions
No. Moving first is a real advantage, but it is not enough to force a win. A second player who knows the correct replies can always reach a draw.
Yes, it is completely solved. If both players play optimally the game always ends in a draw, and the second player can guarantee at least a draw from any opening. Every win in practice comes from a mistake by one side.
A fork is a single move that creates two winning threats at the same time. Since your opponent can only block one threat per turn, the other one completes on your next move. Forks are how you actually win against an opponent who is not playing perfectly.
The centre is the strongest square on its own merits because it belongs to four winning lines. A corner is the best practical trap, though, because it leaves your opponent only one non-losing reply.
Yes. Noughts and Crosses is the Commonwealth name, Tic Tac Toe is the North American one, and Xs and Os is common in Ireland and Canada. The rules are identical.
