How to win at Tic-Tac-Toe (and never lose again)

Can you always win at Tic-Tac-Toe?

Not quite. If both players make the best move every time, Tic-Tac-Toe always ends in a draw. What you can do is make sure you never lose, and win every time your opponent makes a mistake. That is exactly how strong players (and the computer's top character, Grandmaster Owl) play.

The good news: there are only a few ideas to learn. Once they click, most games against friends turn into wins for you, and you can practise them against the computer in Tic-Tac-Toe Plus.

The two questions to ask on every turn

Before anything clever, build this habit. Every single turn, check in this order:

1. Can I win right now? If you have two in a row with the third square empty, take it.
2. Do I have to block? If your opponent has two in a row with an empty third square, block it now.

Most games between beginners are lost by skipping one of these checks. Only when the answer to both is "no" should you think about strategy.

The best first move: take a corner

When you play first (X), start in a corner. The centre is safe too, but a corner gives your opponent the most ways to go wrong. In fact, there is only one good reply to a corner opening: the centre. Every other reply lets X force a win.

Here is the classic trap. You (X) take the top-left corner. If O answers on an edge, such as the top-middle square, you take the centre. Now you threaten the diagonal, O must block in the bottom-right corner, and you take the bottom-left corner. You now threaten two lines at once (the left column and the other diagonal), and O can only block one.

Forks: how you actually win

A fork is a move that creates two threats at the same time. Your opponent can block one, but not both, so your next move wins. Nearly every Tic-Tac-Toe win comes from a fork.

To spot fork chances, look for an empty square that sits on two lines where you already have one mark and the other squares are empty. Corners are powerful because each corner sits on three lines (a row, a column and a diagonal).

• Two of your marks in opposite corners plus an empty third corner often adds up to a fork.
• A mark in the centre plus a corner creates threats along the diagonal and the edges.
• Count the lines through a square before you play there: more lines means more fork potential.

The daily "win in 2" puzzles in Tic-Tac-Toe Plus are all fork puzzles. Solving one a day is the fastest way to start seeing them.

Playing second: how to never lose as O

Playing second is about defence. Remember these replies and you will never lose:

• If X starts in a corner, take the centre. Any other move loses against perfect play.
• If X starts in the centre, take a corner. Taking an edge gives X a winning attack.
• If X starts on an edge, the centre is the simplest safe reply.

After that, if X has corners on opposite sides of the board (a common trap), play on an edge rather than another corner. That forces X to block you, which stops them from setting up their fork.

Common mistakes

• Forgetting to block because you were busy planning your own line.
• Answering a corner opening with an edge or another corner instead of the centre.
• Making a threat that your opponent blocks with a move that also creates their own threat.
• Playing on autopilot: the board is small, so read every line before each move.

Ready for more? Try bigger boards

Once you can hold the computer to a draw, the 3×3 board has taught you everything. The same ideas (centre control, forks, blocking with a threat) power deeper games:

• 4×4 Tic-Tac-Toe: four in a row on a bigger board, with fewer draws. It's in the variants menu of Tic-Tac-Toe Plus.
• Ultimate Tic-Tac-Toe: nine small boards inside one big board, where every move decides where your opponent plays next.
• Four in a Row: drop discs into columns; gravity makes the threats sneakier.
• Five in a Row: the classic Gomoku on a big grid, where forks become "double threes".

Frequently asked questions