peer2peergames

Tic-tac-toe

Three minutes to learn and a lifetime to draw. Worth knowing before you start that against anybody who is paying attention, this game is a draw every single time.

Play Tic-tac-toe Leaderboard

The rules

  1. The board is three squares by three, empty at the start.
  2. One player is X and the other O. X always goes first.
  3. Take turns claiming any empty square. A claimed square cannot be taken back or moved.
  4. Three of your marks in a straight line wins: along a row, down a column, or corner to corner.
  5. If all nine squares are filled and neither player has a line, the game is a draw.

How a game ends

  1. A line of three wins immediately.
  2. A full board with no line is a draw, and a draw is recorded as a draw rather than as a loss for anybody.
  3. A resignation or a missed deadline ends the game against the player who resigned or ran out of time.

Why it is always a draw

  1. Tic-tac-toe is small enough to be solved completely: every possible game has been worked out.
  2. With correct play by both sides the result is always a draw, so a win only happens when somebody makes a mistake.
  3. The bot here plays the game out perfectly and will never lose. Drawing with it is the best result available.

The seed decides who plays X and therefore who moves first, and the seed is published when the game ends, so it can be checked afterwards.

Playing it here

  • Against a person or the bot. The bot needs no account and starts at once. To play a person, be rated and keep your games, you need an account: an email address and a password.
  • At your own pace. Every move has a deadline you both see, from one minute to a week. A game can take an evening or it can take a fortnight.
  • Nothing to buy and nothing to win. No stakes, no prizes, no boosts, no undo. The only thing on offer is a place on a leaderboard, and only if you want one.
  • Every game can be checked. Anything decided by chance comes from the game's seed, and the seed is published the moment the game ends, so any finished game can be replayed and verified by anyone. See fair play.