Place three X marks in a row before the computer places three O marks.
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Place three X marks in a row before the computer places three O marks.
Complete guide
Tic-Tac-Toe is the complete three-by-three line game against a deterministic browser opponent. You play X, the computer plays O, and each square can be used once.
Select any empty square to place X. The browser then chooses one legal square for O; occupied squares never change and cannot be selected again. A horizontal row, vertical column, or either diagonal containing three identical marks ends the round immediately.
The opponent first completes an available winning line, then blocks an immediate X win. If neither exists it prefers the center, useful corners, and finally the remaining edges in a fixed order. The strategy is deterministic, so the same position always receives the same reply.
A single open pair is easy to block. Strong play places marks so two different lines could be completed on the following turn, often by combining a corner with the center. Check every row, column, and diagonal created by your move before choosing a tempting isolated square.
Use the arrow keys to move focus around the logical grid and Enter or Space to mark the focused square. If all nine squares fill without a line, the round is a draw rather than a loss. Start a new round to clear every mark and return focus to the first square.
The player always uses X and takes the first turn; the deterministic browser opponent responds with O.
No. As soon as either mark completes a line, or all squares fill for a draw, further placements are disabled.
No. It is a local deterministic rules function, so no moves, board positions, or personal details are sent to another player.
