How do you play Tic Tac Toe?
Two players take turns placing X and O on a 3×3 grid. The first to fill a row, a column or a diagonal with three of their own marks wins. If all nine squares fill up with no line, the game is a draw.
The game is also known as Noughts and Crosses, or Xs and Os. In this version you play X and the computer plays O.
What are the rules?
| Board | The classic 3×3 grid, with 4×4 and 5×5 boards as options. |
|---|---|
| Moves | On your turn, place one mark in any empty square. Marks never move once placed. |
| Winning | Three in a row on 3×3, four in a row on 4×4 and 5×5, across, down or diagonally. |
| Draw | Every square is filled and nobody made a line. |
| First move | Choose me, the computer or alternate. With two players it is X first, O first or alternate. |
How do the computer levels differ?
Easy plays almost at random. Normal only looks for a winning move or a block and slips up now and then. Hard reads every line to the end and never loses on 3×3. Perfect play from both sides always ends 3×3 Tic Tac Toe in a draw, so a draw is the best result against hard.
On 4×4 and 5×5 the computer looks several moves ahead and weighs how promising each line is. The bigger boards make four in a row much harder to finish, so games turn into long blocking battles.
How do you win at Tic Tac Toe?
- If you go first, take the center or a corner. The center sits on four lines and each corner on three.
- Block two in a row right away. Miss a line with one gap left and you lose on the next move.
- Look for a fork. A move that sets up two winning lines at once cannot be fully blocked.
- If your opponent opens in a corner, take the center. Answering on an edge leaves you open to a fork.
The scoreboard counts your wins, draws and computer wins game by game. Your record for each board and level, plus your last settings, is saved in this browser. If you like longer lines, try Gomoku too.