Starting with an empty grid of points, two players take turns by adding a single horizontal or vertical line between two adjacent points that are not joined. The player who finishes the fourth side of a 1 × 1 box wins a point and takes another turn. (A point is usually recorded by placing a mark that identifies the player in the box, as an initial.) The game ends when no other line can be placed. The winner is the player with the most points. The board can be of any size. When you run out of time, a 2 × 2 chart (a 9-point square) is good for beginners. A 5 × 5 is good for the experts.