Duetly

Tic Tac Toe vs Computer

By Duetly Editorial · Published 2026-08-30 · Updated 2026-08-30

Playing the computer is the fastest way to test whether you actually block threats. A friend will eventually be polite. Hard mode will not.

Easy

Easy chooses randomly among empty cells. You should win most games once you know the eight lines. Use it with a child, or when you want to practice finishing a fork you already set up.

Hard

Hard uses minimax. It will take a win on the spot, block your win, and refuse to walk into a fork. The honest goal is a draw. If you win, the implementation has a bug — and our tests exist to keep that from shipping.

A useful drill

  1. Play five Hard games as X. Count draws.
  2. Play five Hard games and deliberately open on a side cell. Notice how quickly you are fighting.
  3. Play Easy and try to win in as few moves as possible by forcing forks.

When the drill is boring, you are ready to play Tic Tac Toe with a friend. People miss blocks. That is the entertainment.