Ultimate Tic-Tac-Toe
Nine small boards in one. Your move picks where your opponent plays.
How to play Ultimate Tic-Tac-Toe
Ultimate Tic-Tac-Toe is a clever twist on classic Tic-Tac-Toe. The big board is a 3×3 grid, and each of its nine squares holds a small 3×3 board of its own. Two players, X and O, take turns. X goes first.
Goal
Win three small boards in a row: across, down or on a diagonal of the big board. You win a small board the normal way, with three of your marks in a line inside it.
Turn by turn
- The first player may play in any cell of any small board.
- Your move sends your opponent. The position of the cell you play inside its small board is the small board where your opponent must play next. Play the top-right cell of any board, and your opponent must play in the top-right board.
- The boards where you may play are lit up in your colour, so you never have to work it out yourself.
- Free move. If you are sent to a board that is already won or completely full, you may play in any open board instead.
- When someone gets three in a row in a small board, they win it and a big X or O covers it. A won board is closed: nobody can play there again. A full board with no line counts for nobody.
End of the game
The first player to win three small boards in a line on the big board wins the game. If every small board is won or full and nobody has a line of three, the game is a draw.
Playing the computer
Easy often plays at random. Medium thinks a little before each move. Hard plays out tens of thousands of possible games in about a second before it moves, and it is tough to beat. Choose who goes first, and use Undo if you misclick. You can also play with the arrow keys and Enter.
Strategy tips
- Think about where you send your opponent. Every cell you pick is also a choice of board for them. Do not send them to a board where they can win at once.
- Avoid giving free moves. Sending your opponent to a board that is won or full lets them play anywhere. That is often the strongest move in the game, so give it away as rarely as you can.
- The centre board matters most. Just like in normal tic-tac-toe, the middle board is part of four big lines. Corners are part of three.
- Small wins are not everything. Winning a corner board that leads nowhere is worth less than keeping control of where the game goes. Watch the big board first.
- Make your opponent play into boards you control. If you already have two in a row inside a board, try to make them send you there.
- Plan two moves ahead. Before you play, look at the board you are sending your opponent to, and at the board their best reply would send you to.
Ultimate Tic-Tac-Toe FAQ
What happens when I am sent to a board that is already won?
You get a free move. You may play in any small board that is still open. Won boards and full boards are closed for the rest of the game.
Is Ultimate Tic-Tac-Toe the same as Super Tic-Tac-Toe?
Yes. It is also called Meta Tic-Tac-Toe or Tic-Tac-Toe squared. Some groups let players keep playing inside boards that are already won; on this site won boards are closed, which is the most common rule.
Can a game end in a draw?
Yes. If every small board is won or full and nobody has three boards in a row on the big board, the game is a draw. A full small board with no line belongs to nobody.
How does the Hard computer play?
It uses Monte Carlo tree search. In about one second it plays tens of thousands of quick random games from the current position and picks the move that wins most often.
