Linage

Linage is a finite territory game for two players: Vertical and Horizontal. It is played on the intersections (points) of an initially empty square grid (board). Both players must have access to a shared pool of identical stones. Definitions A region is an empty point along with all points one can reach from it through a series of steps onto orthogonally adjacent empty points. A line is three orthogonally contiguous empty points on the same row or column. A region is owned by Vertical if it contains no horizontal lines, and by Horizontal if it contains no vertical lines. A region is free if it is owned by neither player. Play Vertical plays first, then turns alternate. On your turn, pass or place a stone in a free region. At all times, every region must include at least one line. The game ends when both players pass in succession. The player with the higher score wins. Your score is the number of points in the regions that you own, plus komi in the case of Horizontal. The button is used to avoid ties. Komi and button Komi is the whole number of points that is added to Horizontal's score at the end of the game as compensation for playing second. Before the game starts, the first player chooses the value of komi, and then the second player chooses sides. Alternatively, experienced players may agree on a standard value for all games. The button is a special token that is placed next to the board at the start of the game. On your turn, if neither player has taken the button yet, you may not pass, but you may take the button instead of making a board play. At the end of the game, a half point is added to the score of the player who has taken the button.