Tic Tac Toe

Overview

Two players alternate marking squares on a 3×3 grid. The first to place three of their marks in a row wins.

No governing body publishes rules for this game. This page describes the most common form. House rules vary, so agree them before you start.

Play

1. Decide who is X. X always moves first.
2. Players alternate, each marking one empty square per turn.
3. A player wins by completing any row, column or diagonal of three marks.
4. If all nine squares are filled with no line completed, the game is a draw.

Strategy note

With correct play from both sides, tic-tac-toe always ends in a draw. We checked this by working through every possible game. Against an imperfect opponent, many players like to open in a corner.

Variations

• Misère — completing three in a row makes you the loser.
• Gomoku — played on a 15×15 grid, aiming for five in a row.
• Ultimate Tic Tac Toe — nine boards in a grid, where your move dictates which board your opponent must play in next.