How to play Tic-Tac-Toe
Tic-Tac-Toe is the purest duel there is: nine cells, two marks, three in a line. Simple enough to learn in seconds, tight enough that perfect play always draws.
The goal: claim three cells in a straight line — a row, a column, or a diagonal — before your opponent does. If all nine cells fill with no line, the game is a draw.
Rules
- Played on a 3×3 grid, nine cells in total
- X moves first, then players alternate
- One mark per turn, placed in any empty cell
- Marks never move once placed
- Win: three of your marks in a row, column, or diagonal
The shapes that win
Three in a line
Any row, column or diagonal of three ends the game.
The fork
One placement that creates two winning lines at once — unanswerable.
Centre control
The centre cell sits on four winning lines; a corner on three; an edge on two.
Forced block
Two in a row with an open third — you must take that third cell or lose.
Strategy
1. Take the centre if you are first
The centre belongs to four of the eight winning lines. It is the single strongest opening move and the hardest to punish.
2. Otherwise take a corner
A corner sits on three lines and gives your opponent the most chances to go wrong. Against a weak opening it is the move that wins.
3. Always answer a two-in-a-row
If the opponent has two with an open third, blocking is not optional. Missing it loses immediately.
4. Look for the fork, and deny theirs
A fork creates two threats at once. Occupy the cell that would give your opponent a fork, and aim to create your own.
Pro tip: with perfect play from both sides, Tic-Tac-Toe always ends in a draw. Winning is about spotting the one move your opponent does not answer.
Playing here
Modes on BoardDuel: vs AI — play a live engine at three difficulty levels; Pass & play — two players, one screen; Friend room — share a six-character code and play remotely.
Frequently asked
Can the first player always win?
No. If both players play perfectly the game is a draw — the second player can always block. First-player wins come from a missed block.
What happens if the board fills?
It is a draw. Nine cells fill fast, so draws are common between experienced players.
Is the corner or centre better?
The centre is the strongest first move. If the centre is taken, a corner is the best reply.