Tic Tac Toe Rules and Strategy: How to Win (or Never Lose)

Want to know how to win tic tac toe? The rules take ten seconds, but a little strategy turns you from a lucky winner into a player who never loses. Tic tac toe (also called noughts and crosses) is a two-player game on a 3 by 3 grid where you try to get three marks in a row. With perfect play from both sides every game ends in a draw, so the trick is spotting the traps that make an opponent slip. Below are the official rules, a step by step strategy for X and for O, and the brilliant bigger version called ultimate tic tac toe. Looking for more quick games? Browse our classroom games.

Quick rules

• Draw a 3 by 3 grid of nine squares.
• One player is X and the other is O. X goes first.
• Players take turns writing their mark in any empty square.
• The first player to make three in a row (horizontal, vertical or diagonal) wins.
• If all nine squares fill up with no row of three, the game is a draw, often called a cat's game.
• Swap who goes first after each game.

What you need

• Paper and a pencil, a whiteboard, chalk on a sidewalk, or sticks in the sand.
• Two players. For a group, run a quick knockout with the team generator to make pairs.

Setup

1. Draw two vertical lines crossed by two horizontal lines to make nine squares.
2. Decide who is X. Toss a coin, or let the younger player choose.

How to play

1. X marks any empty square.
2. O marks any empty square.
3. Keep alternating. You cannot mark a square that is already taken, and you cannot skip a turn.
4. As soon as one player has three in a row, they draw a line through it and win.
5. If the board fills with no winner, it is a draw.

Scoring

A single game has no points: win, lose or draw. For a match, use this simple table and play an even number of games so each player starts the same number of times.

How to win tic tac toe as X (first player)

Every winning move follows two rules in order: first, if you can make three in a row, do it. Second, if your opponent has two in a row, block it. When neither applies, use these plans.

The corner opening

1. Start in a corner. It gives O the most ways to go wrong.
2. If O plays anywhere except the center, you can force a win. For example, if O takes an edge or a corner other than the center, take another corner so you threaten two lines at once.
3. The goal is a fork: a move that creates two lines of two at the same time. O can only block one, so you win with the other.
4. If O takes the center, take the opposite corner. If O then plays a corner, block it and you will have a fork. O's only safe reply is an edge square, which leads to a draw.

The center opening

Starting in the center is safe, but it only wins if O answers with an edge square. Then take a corner and look for a fork.

How to win tic tac toe as O (second player)

• If X starts in a corner, take the center. Any other reply loses against good play.
• If X starts in the center, take a corner. An edge reply lets X build a fork.
• If X starts on an edge, take the center or a corner next to X's mark.
• The opposite corner trap: if X holds two opposite corners and you hold the center, play an edge, not a corner. Playing a corner here lets X fork you.
• As O you mostly aim for a draw, then win when X makes a mistake.

Can you win tic tac toe every time?

No. If both players follow the strategy above, every game is a draw. What you can do is never lose, and win every time your opponent misses a block or walks into a fork.

Variations

• Ultimate tic tac toe: a big 3 by 3 grid where each square holds a small tic tac toe board. The square you play in on a small board tells your opponent which small board they must play in next. Win a small board to claim that square of the big board; three big squares in a row wins. If you are sent to a board that is already won or full, you may play anywhere.
• Bigger boards: play on 4 by 4 and need four in a row, or 5 by 5 with four in a row.
• Three-piece version: each player has only three marks. After placing all three, you move one of yours to an empty square each turn.
• Misere tic tac toe: making three in a row loses.
• Giant lawn version: use rope for the grid and flying discs or beanbags as pieces at a party.

Tips and strategy

• Always check for a win, then a block, before anything else.
• Corners belong to three lines, the center to four, and edges to only two, so edges are the weakest squares.
• Look one move ahead for forks, both yours and your opponent's.
• Practise both sides. Many players only learn to attack as X.

Common mistakes

• Forgetting to block an obvious two in a row.
• Answering a corner opening with an edge as O.
• Letting the same player go first every game.

For more pencil and board fun, try checkers or the bigger strategy of chess, and see our board games for kids.