Tic Tac Toe

Tic Tac Toe (also called noughts and crosses) is probably the first strategy game most of us ever learned: two players, a three-by-three grid, and a simple goal — place three of your marks in a row, across, down or diagonally. Our version runs in any browser on a phone, tablet or computer, and it offers three ways to play so you can always find a game.

Three ways to play

vs Computer – Easy. The computer sometimes plays a random square, so you can win and learn the patterns without pressure.
vs Computer – Unbeatable. The computer searches every possible future of the game using the minimax method with alpha-beta pruning. The best you can do against it is a draw, which makes it a fun challenge: can you ever force one?
2 Players. Pass the phone back and forth with a friend or a family member sitting next to you.
Play a Friend Online. One player taps “Create a room” and gets a five-character code. The other player enters the code under “Join room”. The two browsers then connect directly to each other, and you can play live from different houses or even different cities.

How online play works

For the online mode we use WebRTC, a technology built into modern browsers that lets two devices talk to each other directly. A free public broker only introduces the two browsers; moves travel straight between the players, and we do not store them or ask for an account. If the connection cannot be made, for example on a very strict office network, the game tells you and you can try again or switch to another mode. Keep the room screen open until your friend joins.

Can the game always be drawn?

Yes. With perfect play from both sides, tic tac toe always ends in a draw. That is why the strongest strategies are really about not making mistakes. If you go first, take the centre or a corner. If your opponent takes the centre, reply with a corner. Always look for a move that creates two threats at once, called a fork, because your opponent can block only one of them. And before every move of your own, check whether your opponent is one square away from three in a row.

Why this old game is still worth playing

Tic tac toe teaches ideas that appear in every strategy game: looking ahead, thinking about what your opponent wants, and balancing attack with defence. It is also an excellent first game for children, who can learn to take turns, notice patterns and accept a draw gracefully. Because a round takes under a minute, it is perfect for a short break or a waiting room.

Controls and tips

Tap or click a square to place your mark. On a keyboard you can also press the keys 1 to 9 to choose a square in reading order. The starting player alternates every round, and your wins, draws and losses are shown below the board. On the harder computer level, each win scores points toward your best score. Everything runs inside your browser, the game works on any screen size, and there are no downloads, pop-ups or purchases.