Trilithon (1999)

Trilithon is a connection game with a symmetric winning condition for a hexagonal hex board. It has been described somewhat wrongly (as Obtuse Y) in Cameron Browne's book Connection Games.

The correct rules are: the edges of the hexboard are labeled from A to F in a clockwise manner. A is top, B is upper right, C is lower right, D is bottom, E is lower left, and F upper left. Edges form so-called pairs: A with B, C with D, and E with F. An edge is said to be completed by a player, if both edges of the pair and a third one not in that pair are connected by an unbroken chain of stones belonging to that player. The player who completes two pairs wins. Only one player can win, and there are no draws possible.

Example: if a player connects the edges A, B, C, and D, he has won the game.

The usual rules for connection games apply. Players take turns, and the first move can be swapped according to the pie rule. Corners belong to both edges.