Paper Games
How to play Tic-Tac-Toe
Take turns placing X and O in a three-by-three grid; three of your marks in one line wins.
What you need
Paper and pencil, a chalk grid, or a simple digital board
Set up the game
- Draw two vertical and two horizontal lines to form nine squares. Assign X and O; agree who starts and alternate that privilege over multiple rounds.
Place marks and check for a line
- The first player marks one empty square. Players alternate placing their own mark in any empty square; a filled square cannot be used again.
- After every placement, check the three rows, three columns and two diagonals. A player who has three of their own marks in one line wins immediately.
- If all nine squares fill with no line of three, the round is a draw. Start another fresh grid if playing more rounds.
A forced block
X holds the upper-left and upper-middle squares; O has the center. It is O's turn. O must mark upper-right unless O can already win elsewhere, because otherwise X takes upper-right next turn to complete the top row. This is a line threat, not a matter of total marks.
Spot a fork before it forms
A fork is one placement that creates two open winning threats on the next turn. If your opponent can make such a move, simply blocking one existing line may be too late. Check both diagonals and the rows through the center whenever two corners are in play.
Beginner decisions
- A center mark participates in four possible winning lines; a corner participates in three.
- If the other player has two marks in a line and the third space is open, block that space unless you can win now.
Common rule mix-ups
- Marking a filled square or continuing to play after a line of three has already formed.
- Treating three marks in an L shape as a line; a win must be a straight row, column or diagonal.
Questions about this game
Can both players win on the last move?
No. A legal move places only one player's mark; stop as soon as that move makes their line.
How are repeated rounds scored?
A best-of-three or one point per win is an optional house format; the basic round has only win or draw.
Sources and edition notes
Standard 3×3 pencil-and-paper tic-tac-toe. This traditional game has no single official rule publisher; the chosen convention is one mark per turn, straight line of three, draw on a full grid.