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Tic-Tac-Toe Strategy and Tips

Here is how to think about winning at Tic-Tac-Toe, split into short lessons. Each one reads on its own, and each one comes with a real position: press Try it on the board and you play the move yourself.

After a corner, take the centre

Lesson 1

On a 3x3 grid, not every square touches the same number of lines. The centre sits on all four possible lines (across, down and both diagonals). A corner sits on three lines (one each direction it can reach), and a middle-edge square sits on only two. A square that touches more lines gives your mark more directions to grow into, which is why it is worth more early in the game.

The basic opening principle is simple: play the centre or a corner first, and keep following that principle on later moves too. In this position, you have already played a corner, and your opponent answered with a middle-edge square. The centre is still open. Taking it now gives you both a corner and the centre, a combination that can grow toward several different lines at once.

If you let your opponent take the centre instead, they gain access to all four lines while your single corner only reaches three. Whenever the centre is open, check it before you consider a middle-edge square — it is almost always the stronger move.

Block a pair immediately

Lesson 2

Tic-tac-toe has a well-known property: with best play from both sides, the game always ends in a draw. There is no secret opening that forces a win. What does exist is a reliable way to never lose, and the most basic part of it is this: whenever you cannot make three yourself, block your opponent's two in a row. Miss that single move and the game is decided on your opponent's very next turn.

In this position, O has two marks along a diagonal, and the third square on that line is still open. Leave it open and O completes the diagonal to win. Even if you have a plan of your own building up, blocking that square has to come first.

The square to take is always the missing third square of your opponent's pair, and pairs can appear on any row, column or diagonal. Get into the habit of scanning the whole board on every turn for a two-in-a-row before you decide your own move — that habit alone is enough to stop you losing games by accident.

Create a double threat

Lesson 3

One of the few positions where you can force a win in tic-tac-toe is the double threat, sometimes called a fork. Playing a single empty square puts two different lines — some pair of a row, a column or a diagonal — one square away from completion at the same time. Since your opponent can only play one square on their turn, they can block just one of the two lines. Complete the other one on your next move and the game is yours.

In this position, you already hold two corners. Your opponent's mark sits in the centre, which kills the diagonal between your corners, but the row and column running through each corner are both still open. Play the square where that row and that column cross, and both lines become one move away from three at once.

The trick to spotting a double threat is looking for two of your own lines that are not yet blocked and checking where they cross. If they meet at a single empty square, that square is your candidate. The same idea works in reverse: if your opponent could create the same shape, taking that crossing square yourself first is the strongest way to defend against it.

Think about where you send them (Ultimate)

Lesson 4

The single most important rule in Ultimate Tic-Tac-Toe is that you never choose which small board to play in next. Whichever position your opponent's last move occupied inside its own small board determines the small board you are sent to. Because of this, deciding your move means weighing two questions at once: which small board can I win with this move, and — just as important — which small board does this move send my opponent to?

In this position, playing the bottom-right square wins the centre board outright, completing three in a row there. But that exact position, bottom-right within its board, sends your opponent to the bottom-right board on the big grid — and your opponent already has two in a row waiting there. Handing them a free move in a board they can finish immediately gives back more than the small win was worth.

Playing the left square instead doesn't complete the centre board yet, so there's no immediate win. What it does buy you is safety: that position sends your opponent to a small board nobody has touched. Winning a board right now can look tempting, but checking where your move sends your opponent first is often worth more than the board itself. Make that check a habit before you commit to a move.

Try it on the board

Pick a lesson and the board starts from that position. Start over as often as you like.

Now put it to work

Play with friendsLearn how to play (3 min)

Last updated 2026-09-23 · Run by Qdan, Inc.