Description

Linage is a finite territory game for two players: Vertical and Horizontal. It's played on the intersections (points) of an initially empty square board. Both players must have access to a shared pool of identical stones.

A region is a maximal set of orthogonally contiguous empty points.

A line is a set of 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's owned by neither player.

Vertical plays first, then turns alternate. On their turn, a player must either pass or place a stone on an empty point which is part of a free region. At all times, every region must include at least one line.

When both players pass in succession, the game ends. A player's score is the number of points in the regions that they own, plus a komi (see below) in the case of Horizontal. The player with the highest score wins.

The komi is the number of points which is added to Horizontal's score at the end of the game as a compensation for playing second. Before the game starts, the first player chooses the value of komi, and then the second player chooses sides. To avoid ties, it is suggested that komi be of the form n + 0.5, where n is a whole number.