Three marks in a row
Tic Tac Toe fits on nine squares. Two players share the grid, one placing X and the other O, taking turns to drop a mark in any empty square. The target is three of your own marks in a straight line, across, down or on a diagonal. It is the rare game a child grasps fully in a single turn, and yet, as most soon find, understanding the rules and actually never losing turn out to be two different things.
How to force a win, or a draw
The center square touches more winning lines than any other, so taking it first is usually right. From there the game turns into a contest of threats: whenever an opponent lines up two, you have to grab the third square to block, and whenever you can, you hunt for a move that opens two lines at once, since a double threat cannot both be stopped. That double threat is the only way past a careful opponent, which is exactly why so many even games end in a draw.
A first lesson in seeing ahead
For many children this is the first game that asks not just what does my move do, but what will my opponent do in reply. Because the whole board is in view and the games are over in a minute, a child can play, lose, and try a sharper idea straight away, learning the feel of setting a trap and catching one. It travels anywhere too, on paper, in the sand, or here against a computer that gives nothing away on Hard.
Frequently asked questions
How do you play Tic Tac Toe?
Players take turns putting their mark, X or O, in the empty squares. The first player to get three of their marks in a row, across, down or diagonally, wins. If the board fills up with no three in a row, it is a draw.
Can the computer be beaten at Tic Tac Toe?
On Easy, yes, it makes mistakes you can punish. On Hard it plays a perfect game, so the best you can force is a draw and never a win. That is not a flaw: Tic Tac Toe is a solved game, so two players who both play perfectly always tie. Beating Hard is impossible, but never losing to it is a real skill.
Why does Tic Tac Toe often end in a draw?
Because the board is tiny and both players can see every threat coming. Once children learn to take the center and block a line of two, most games between evenly matched players end tied. The fun then shifts to setting a double threat, two ways to win at once, which is the only way to force a win against careful play.