Step 1: Open with the Center (or a Corner)
Your first move matters more than any other move in the game. Pick well and you set up threats for the rest of the game. Pick poorly and you're already on defence.
Why the Center Wins
The center square sits on four winning lines - One row, one column and both diagonals. No other square touches that many. If you move first, take the center. It gives you the most ways to build threats later.
| Square type | Winning lines | Opening strength |
|---|---|---|
| Center | 4 | Best - Take it if you move first |
| Corner | 3 | Second-best - Carries a trap (see below) |
| Edge | 2 | Weakest - Avoid opening here |
The Corner Trap
Corners are the second-best opening. They also hide a trap for your opponent. Say you open in a corner. If your opponent replies anywhere except the center, you can usually force a fork and win. Edges (the middle square of each side) are the weakest opening of all, since they touch only two lines.
Step 2: The Two Questions to Ask Every Turn
Most lost games come from skipping one of two checks. Ask them in order, every single turn.
The Two-Question Check
- Can I win right now? Scan your own marks for a line of two with an empty third square. If it exists, take it - Immediately.
- Can my opponent win next turn? Scan their marks the same way. If they have two in a line with an open third square, you must block it.
Discipline Over Brilliance
Discipline beats brilliance here. Even strong players lose games by getting excited about their own plan. They forget to check the board and miss an opponent's open line.
Step 3: Win with the Fork
A fork is the winning weapon of tic tac toe. It's a single move that creates two winning threats at once. Your opponent can only block one. You win on the next move, guaranteed.
The Classic Corner Fork
Here's a classic corner fork. X holds both top corners and the center. That center mark sits on both diagonals, so X now has two winning threats at once - The two highlighted corners (marked squares are X's winning options):
X threatens both diagonals through the center - One is completed by the bottom-left corner, the other by the bottom-right. O can only block one. X wins on the other.
Building Your Own Forks
Look for intersecting lines. A corner plus the center is one pattern. Two corners that share a row or column is another. Place your marks there, and quietly build both threats before your opponent notices. For a full walkthrough of a fork in action, see What Is a Fork in Tic Tac Toe. It includes a real board where a player misses one and loses.
Step 4: Stop Your Opponent's Forks
Everything above works against you too. Two defensive habits cover most fork setups.
Answer the Corner Opening
If your opponent opens in a corner, take the center. The center blocks most corner-fork patterns before they can start.
Block With Purpose
- When you block, block with purpose. If you have a choice of blocking squares, pick the one that also creates a threat of your own. A forced defence buys you the move you need.
- Watch the double corner. If your opponent holds two opposite corners and you hold the center, don't respond in a corner - Play an edge instead. A corner reply hands them a fork.
Can You Always Win?
No - And it's worth knowing why.
Why It's Always a Draw With Perfect Play
Tic tac toe is a solved game. Mathematicians have mapped all 255,168 possible games. With perfect play from both sides, the result is always a draw. Wins only happen when someone makes a mistake. That's exactly what our Hard mode shows you. It plays the perfect strategy, so the best you can achieve is a draw, every time.
How to Win Against Real Opponents
Realistically, most opponents aren't perfect. Against human players and our Easy and Medium computers, the strategy on this page wins consistently. Open in the center or a corner, hunt for forks, and you'll win the large majority of decided games. More questions about the game itself? Check the FAQ.
Winning on the 5×5 Board
On our 5×5 board you need four in a row. The strategy shifts from memorised patterns to reading threats as they form.
The Open Three
The open three is the fork of 5×5. It's three of your marks in a row with both ends empty, which gives you two different winning squares - Normally unstoppable. Build toward open threes of your own, and block your opponent's before they complete.
Control the Central Nine Squares
The nine squares in the middle of the board sit on far more four-in-a-row lines than the border squares do. Holding them gives you more ways to build threats, the same way the center does on the small board.
The highlighted squares above are the central nine. Fight for them early, the same way you'd fight for the center on a 3×3 board.
Dual-Purpose Moves
The strongest placements extend two of your lines at once - A row and a diagonal, for example. Look for a single square that helps two plans at the same time, instead of one square that only helps one.
Practise the Strategy
Reading only gets you so far. The fastest way to make this strategy stick is to try it against a live opponent.
Practise Against the Computer
Work up through the difficulty levels one at a time. Start with Easy mode to practise the two-question habit with no pressure. Move to Medium mode once that's automatic. It blocks properly, so only a real fork will beat it. That makes it perfect fork training. When you're ready for the final exam, try Hard mode and see if you can force a draw from every opening.
Play With Others or Level Up
Once you've got an edge over the computer, take it to 2 player mode and test it on a friend. When you've outgrown the classic board entirely, Ultimate tic tac toe is where the strategy goes next.