Tic Tac Toe

Tic Tac Toe is the classic 3×3 grid game, also called Noughts and Crosses or Xs and Os, in which two players alternate marking empty squares with X and O. Using mouse clicks or taps to claim a square, the objective is to line up three of your marks in a row, column, or diagonal before your opponent does. Play a friend on the same device, or take on eight AI difficulty levels from Goofy up to Impossible.

Controls

• Place a mark: Click or tap any empty square on the grid.
• Hint: A dimmed mark appears on the suggested square during your turn.
• Menu: Use the toolbar under the board for Restart, 1 or 2 players, Sound, Best scores and Settings.

How to Play

1. Take turns with your opponent placing X and O marks on the nine squares of the grid. X moves first by default.
2. Win the round by completing a line of three of your own marks — horizontally, vertically, or on either diagonal. There are eight winning lines in total.
3. Block your opponent the moment they get two in a row with the third square still open.
4. If all nine squares fill with no line, the round is a draw, informally called a cat's game.
5. A match runs 12 rounds by default, and the starting player alternates each round so neither side keeps the first-move advantage.

Game Modes

• Human vs AI (default): you play X, the computer plays O.
• Human vs Human: set both seats to Human and share one device.
• AI vs AI: set both seats to AI and watch two engines play each other.
• Custom AI: write and save your own opponent in the User AI tab.

Tips

• The center square sits on four of the eight winning lines, each corner on three, each edge on only two.
• Opening in a corner leaves your opponent just one square (the center) that saves them.
• As the second player, take the center if it is free; if it is taken, take a corner.
• You cannot beat sound defense on one line — win with a fork, a single move that opens two threats at once.
• Tic Tac Toe is a solved game: two players who both play perfectly will always draw.