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Instruo

Strategy

Tic Tac Toe

Make three in a row against a friend or an unbeatable computer opponent.

Play immediately. No account required.

Make three in a row. Play another person or an unbeatable local computer opponent.

Your turn. Place X.

You play X. The computer plays O.

Rules

  1. X takes the first turn, followed by O.
  2. Select one empty square on each turn.
  3. The first player to place three marks in a horizontal, vertical, or diagonal line wins.
  4. If all nine squares are filled without a line, the round is a draw.

Game modes

  • Vs computer: you play X against a local minimax opponent that cannot be beaten.
  • Two players: X and O take turns on the same device.

A brief history

Three-in-a-row games have existed in many forms for centuries. Tic Tac Toe also holds a place in computing history: Alexander Douglas created OXO for Cambridge University's EDSAC computer in 1952, making it one of the earliest computer games.

Source: Computer History Museum.

Privacy

The board and computer opponent run entirely in your browser. No account or network request is required.