Puzzle 20

Win in 6 moves. You play X.

Win in 6 moves, 20 of 20

How it works

  1. Take turns placing X and O. Three in a row wins, as usual.
  2. You can have only three marks on the board.
  3. Your fourth mark makes your first one disappear. The one that goes next is drawn as a dashed outline.
  4. The board never fills up. If the same position comes up three times, the game is a draw.
  5. Opening is an advantage, so players take turns to open each new game.
X takes the top right corner to block O. The dashed X in the top left disappears.