Tic-Tac-Toe
Play Tic-Tac-Toe Online for Free
Three in a row wins, four on the 4×4 board. Leave mid-game and it is still there when you next pick the same opponent.
How to play
Lines run across, down or corner to corner.
- On the start screen, choose Easy computer, Hard computer, Two players or Online with a friend, then press Play.
- Choose 3×3 or 4×4 above the board. You can switch until you place your first mark, even if the computer has already moved.
- Tap an empty square to put your mark there. X always moves first.
- Finish a line to win, and its squares are highlighted. A full board with no line is a draw.
Against the computer you start as X. After that, whoever went second goes first. Two players share one device and the marks never swap, so take turns being X.
Online with a friend is 3×3 only and needs the internet. Pick a name, tap Invite a friend and send the link. Your friend opens it, picks a name and joins; then you tap Start. You are X in the first game, and after that you take turns going first.
There is no undo.
Controls
| Action | Touch | Mouse | Keyboard |
|---|---|---|---|
| Place your mark | Tap an empty square | Click an empty square | Arrow keys or W, A, S, D to move, then Enter or Space |
| Switch 3×3 / 4×4 (before your first mark) | Tap 3×3 or 4×4 above the board | Click 3×3 or 4×4 above the board | Shift+Tab to the size switch, then the arrow keys |
| Choose an opponent | Pick it on the start or result screen | Pick it on the start or result screen | Tab or Shift+Tab to the choices, then the arrow keys |
| Pause | Pause button | Pause button | Esc |
| Resume | Resume button | Resume button | Esc or Enter |
| New game, same opponent | New game button | New game button | Tab to New game, then Enter |
A screen reader reads each square as its row, column and mark, and says where the computer played.
Tips and strategy
Answer a corner opening with the center
When X opens in a corner, only the center holds the draw for O; the other 7 replies lose against perfect play. Against a center opening, take a corner, never an edge.
Set up a fork: two threats in one move
As X, take the top-left corner. If O answers in the top middle, take the center, which forces O into the bottom-right corner. Then take the bottom-left corner:
- Top row: X, O, empty
- Middle row: empty, X, empty
- Bottom row: X, empty, O
X now threatens the middle-left square and the top-right corner, and O can block only one.
Against Easy, open in a corner
Easy is set to take a winning square 3 times in 4 and to block yours half the time; its other moves are random. On 3×3, a computer that never makes a losing move beat it 95 times in 100 from a corner opening, and 86 in 100 from any other.
On 4×4, take the squares that sit on 3 lines
The 4 corners and the 4 middle squares each sit on 3 lines; the other 8 squares sit on 2. A line holding both marks can’t be won, so a 3-line square keeps more lines open for you and closes more to the other side.
About Tic-Tac-Toe
In Britain and much of the Commonwealth the game is called noughts and crosses. It was among the earliest games written for a computer: in 1952 Alexander Douglas, a Cambridge PhD candidate, wrote a version for the university’s EDSAC, played with a rotary telephone dial.
Frequently asked questions
- Can you beat the Hard computer?
- Not on 3×3: Hard has worked out every position there, so a draw is the best you can get. On 4×4 it looks only 4 moves ahead and sometimes settles for a draw it could have won, but it almost never loses.
- Is it better to go first?
- Yes. When both sides pick squares at random, X wins twice as often as O on 3×3, and a little more often on 4×4. With no mistakes on either side, every game on both boards is a draw.
- Can I play with a friend on another phone?
- Yes, on the 3×3 board. Choose Online with a friend, pick a name and send the link. There is no chat, and the room closes when the player who made it leaves or after 30 minutes with no move.
- Are my wins and losses saved?
- Yes, in this browser. The line under the board counts wins for each side and draws, kept apart for Easy, Hard and Two players.
