Tic Tac Toe Strategy

Strategy in Tic Tac Toe is small and sharp. You are not looking for a secret opening book. You are looking for two habits: never miss a block, and create two threats at once when you can.

Priority list

1. If you can win now, take the winning cell.
2. If the opponent can win next turn, block that cell.
3. If you can fork (two winning threats at once), do it.
4. If you can block a fork, do that.
5. Otherwise take the strongest remaining square: center, then corner, then side.

Why the center is strong

The center sits on four winning lines. A corner sits on three. A side cell sits on two. That counting argument is the whole 'opening theory.' It is also why the best first move debate is really a debate about how your opponent replies, not about magic squares.

Forks

A fork is a position where you threaten two different winning lines. The opponent can fill only one cell. Example: you have X in two opposite corners and the center is open or already yours in a way that makes both remaining corners dangerous. Beginners lose here because they stare at the last move instead of scanning all eight lines.

Against people, not against minimax

Perfect play always draws. Real people miss blocks. Your practical plan is: play the priority list without exceptions for the first four moves. Most human games are decided by one skipped block. Hard computer mode will not skip one. Use Easy when you want to practice spotting forks; use Hard when you want to practice not losing.