Black goes first. Place one disc in an empty square so that one or more white discs sit in a straight line between the new disc and another black disc. Lines can run horizontally, vertically or diagonally. All trapped lines flip to your colour in the same move.
You must flip at least one opposing disc. If you have no legal move, your turn passes automatically. The game ends when both players have no move, even if empty squares remain. Count the discs; the larger total wins.
A better opening
Taking the most discs immediately can give away useful squares. Early on, try to keep several possible moves while limiting your opponent’s choices. Avoid the diagonal squares beside an empty corner: they often let the other player claim it.
The Tactical opponent looks ahead; Relaxed uses a shorter search. Or choose “A friend here” and take turns on one device. Games save in this browser and do not affect the daily leaderboard.