Block two in a row
OOXXX
X must take the top-right square. Creating a new threat elsewhere would let O win across the top row.
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Play free against the computer or with another person on the same device—no download, account, or sign-up required.
Game board
Moves in this round
Choose Opponent
Vs Computer · Medium · saved on this device
Wins
0Losses
0Draws
0Win streak / best
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How to Play Tic Tac Toe
Two players alternate placing X and O on a 3×3 grid. X traditionally goes first; the Vs Computer options can change the starting side. The first player to complete a horizontal, vertical, or diagonal line of three marks wins. If all nine squares fill without a winning line, the round is a draw.
The eight winning lines
- Top, middle, or bottom row (3)
- Left, centre, or right column (3)
- Top-left to bottom-right diagonal (1)
- Top-right to bottom-left diagonal (1)
Play modes
Vs Computer: choose Easy, Medium, or Unbeatable in Options, then tap an empty square. 2 Players — Same Device: share this screen and take turns; this is pass-and-play, not remote online multiplayer.
Strategy Examples
The dashed square is the recommended move. “Load this position” opens the example as a two-player practice board.
Create a fork
XOOXX
Bottom-left gives X two next-move threats: the left column and bottom row. O can block only one.
Defend opposite corners
XOOX
When X owns opposite corners and O has the centre, O should take a side—not another corner—to avoid an X fork.
Force the draw
XOXXOOXO
O can occupy either empty square without opening a winning line. X fills the last square, so careful defence secures a draw.
AI Difficulties
Easy
Chooses randomly from every valid empty square. It does not deliberately win or block.
Medium
Takes an immediate win, blocks your immediate win, then prefers the centre, corners, and sides. It does not search the full game tree.
Unbeatable
Uses minimax with alpha–beta pruning to check every legal continuation. It cannot be beaten; perfect play against it ends in a draw.
Privacy and Saved Data
The game runs entirely in your browser and sends no moves, names, or records to a game server. Preferences and records by opponent and difficulty are stored in local browser storage when available. Reset Records clears those results on this device.
Brief history and classroom ideas
Noughts and crosses has long been used to introduce game trees and decision-making. Donald Michie’s 1963 paper described a trial-and-error device that learned the game with matchboxes and coloured counters. A commonly quoted count of 255,168 refers to possible complete game sequences, not “legal positions.”
For a short classroom activity, ask learners to identify all eight winning lines, explain why a move blocks a threat, or compare the choices made by Medium and Unbeatable.
Sources: Wolfram MathWorld: Tic-Tac-Toe; Michie, The Computer Journal (1963); University of Göttingen: MENACE; IEEE CIG 2006 proceedings. Reviewed 18 July 2026.
Frequently Asked Questions
Is this Tic Tac Toe game free?
Yes. The game is free to play, with no download, payment, account, or sign-up required.
How does two-player mode work?
Choose 2 Players — Same Device, then take turns placing X and O on this device. It is local pass-and-play, not a remote online room.
Can Unbeatable Tic Tac Toe be beaten?
No. Unbeatable checks the complete game tree with minimax. Perfect play can force a draw, but the computer will not lose.
Who goes first?
X always moves first in two-player mode. Against the computer, open Options to choose whether you, the computer, or alternating sides start.
How does Undo work?
Against the computer, Undo normally removes your move and the computer reply. In two-player mode it removes one move. After a result, Undo also reverses that result in the saved record.
Are scores and settings saved?
Yes, when browser storage is available. Records and preferences stay only on this device and can be reset from Options.
Does it work on phones?
Yes. The board scales to narrow phone screens and supports touch without horizontal scrolling.
Can I play with a keyboard?
Yes. Tab enters the board, arrow keys move between squares, and Enter or Space places a mark. Number keys 1–9 also choose squares from top left to bottom right.