3×3 · three in a row
The game as everyone knows it: nine cells, three in a row. It is quick, it is the best way to learn forks, and between two players who know it, it is always a draw — which the hardest computer will show you.
Play on this board →Tic-Tac-Toe
The game everyone has played in the margin of an exercise book. On the classic 3×3 board two careful players always draw, so there are two bigger boards as well: four in a row on 4×4, and five in a row on 15×15, where the game really opens up. Play the computer at three levels, or send a friend a link.
Three boards
4×4 · four in a row
Sixteen cells and four in a row: the same game on a board just big enough for threats to hide. A draw with the best play too, but a missed diagonal decides it, and it is far easier to lose.
Play on this board →15×15 · five in a row
Five in a row on a board a page wide, the way it is played across an exercise book in class. Threats build on each other — an open three, a four — and crosses, who move first, have a real edge.
Play on this board →On every board crosses move first, a mark stays where it is put, and a row across, down or corner to corner wins.
How to play
Tic-tac-toe rules: 3×3, 4×4 and five in a row
Three boards, crosses first, a row wins — and how draws, resigning and a table with a friend work.
Tic-tac-toe rules: 3×3, 4×4 and five in a row →How to win at tic-tac-toe: openings and forks
The corner opening, forks, why 3×3 is a draw, and how to build five in a row on the big board.
How to win at tic-tac-toe: openings and forks →