Tic tac toe

About Tic Tac Toe

Tic-tac-toe is a three-by-three grid, two symbols and a solved game: with correct play from both sides it always ends in a draw. That is not a flaw. It is why the game survives — it is short enough to play a hundred times and simple enough that both players can see exactly where they went wrong.

Its ancestor is Roman, a game called terni lapilli played on the same grid with three counters each. The version with nine free squares is the one that ended up in every school exercise book.

How to play

1. Players take turns placing their mark on an empty square. X goes first.
2. The first player to get three of their marks in a row — horizontally, vertically or diagonally — wins.
3. If all nine squares are filled with no line made, the game is a draw.

Controls

Click or tap

Place your mark on any empty square.

Tips

• As X, open in a corner rather than the centre. It gives your opponent only one non-losing reply, and most people do not find it.
• As O against a corner opening, take the centre. Anything else loses with correct play from X.
• Always check for two threats at once. Creating a fork — two lines that each need one more mark — is the only way to force a win against a competent opponent.
• Block before you build. A player who is one move from three in a row must be stopped even if it costs you your own plan.
• The centre square sits on four of the eight winning lines. The corners sit on three each, the edges on two. That ranking is the whole strategy.

Frequently asked questions