Tic tac toe strategy
How to win at tic tac toe: openings, forks and perfect play
You cannot force a win in tic tac toe against a perfect player: every first move leads to a draw if both sides play well. You win by setting up a fork, two lines of two at once, against a player who has not taken the one safe reply. A corner start leaves your rival only one safe reply, the center.
Tic tac toe by the numbers
| First move for X | Result with perfect play | Safe replies for O | Replies that lose |
|---|---|---|---|
| Corner | Draw | 1 of 8 | 7 of 8 |
| Edge | Draw | 4 of 8 | 4 of 8 |
| Center | Draw | 4 of 8 | 4 of 8 |
A game here is every legal sequence of moves from the empty board until someone makes three in a row or the board is full. Counted when this page was built.
Play the corner as X
All three kinds of first move, corner, edge and center, are draws with perfect play. They are not equally hard to answer. After a corner start, only one of the eight replies holds the draw for O: the center. Every other reply loses to correct play by X.
After a center start or an edge start, four of the eight replies are safe. That is why strong players start in a corner against people: it gives the most room for a mistake.
Reply correctly as O
The second player only needs to know three answers.
- X takes a corner: take the center.
- X takes the center: take a corner, never an edge.
- X takes an edge: take the center, a corner next to X's mark, or the edge opposite it.
Make a fork
A fork is one move that creates two lines with two of your marks and an empty third square. Your rival can block only one, so you complete the other. Almost every win between people comes from a fork.
The classic corner fork: X in one corner, O anywhere but the center, X in the opposite corner, then X takes a third corner after O blocks. Two lines are open and the game is over.
Block in the right order
On every move, run the same check, in this order:
- Can I complete a line now? Do it.
- Can my rival complete a line on their next move? Block it.
- Can I make a fork? Do it.
- Can my rival make a fork? Take that square, or force them to block somewhere else.
- Otherwise take the center, then a corner, then an edge.
Sources
- Our own count of the full game tree, computed when this page is built: every legal game from the empty board, and a perfect-play search of every reply to each first move.
- The same perfect-play search powers the hard bot in the app, which never loses.
More strategy
Strategy questions
Is tic tac toe always a draw?
With perfect play by both players, yes. Every opening move can be answered with a draw, so a win needs a mistake from the other side.
What is the hardest opening to answer in tic tac toe?
A corner. Only one of the eight replies, the center, keeps the draw for the second player.
Updated November 4, 2026 by the team.