You are X and always move first. Line up three of your marks — across, down or diagonally — to take the round.
Keyboard
Every empty square shows its number. Press 1–9 to play there without reaching for the mouse. The number row and the numpad both work, and the number matches what you see on screen.
Scoring
A won round is worth 1 point. A drawn round is worth ½ to each side, so a series can never stall. First to the target takes it.
Difficulty
Easy plays at random. Medium alternates between the best move and a random one. Hard solves the whole board, but slips roughly one turn in eight — that slip is your opening.
Shortcuts
H opens this help, Esc closes it, M mutes the sound.