Tic-Tac-Toe

About this test

Tic-tac-toe is probably the most played strategy game in the world and also one of the most misunderstood. People learn it in a playground, write it off as childish, and then keep playing it badly for the rest of their lives. Line-up games on grids have been played since antiquity; the nine-square version is its smallest possible form.

What makes it interesting is that it is completely solved: if both players play perfectly, every game ends in a draw. Winning is therefore never about outsmarting your opponent, it's about waiting for and punishing a mistake. That's why the players who rack up wins are the ones who play slowest.

There's only one concept to master, and it has a name: the fork. It's a move that creates two lines of two at the same time, so your opponent can only block one. Every win at tic-tac-toe is a fork, without exception. And every loss is a fork you didn't see coming, which means defence is less about blocking lines than about spotting, two moves ahead, the square that would create two of them. The opponent here defends properly, but it doesn't build forks and it slips up occasionally — so it can be beaten.

How it works

Five rounds, you always move first. Only wins are counted: a draw is worth nothing, which fits a game where the draw is the default result. The 0-100 score runs from zero to five wins.