MEDUSA

Copyright (c) Christian Freeling

The game starts at an empty 10x10 hexagonal board:

MOVE - A player, at each turn, has the following options: Drop a stone on an empty cell; Move one or more of his groups (a group is a set of connected stones); Drop a stone and then move one or more groups; Pass. GROUP MOVEMENT - Moving a group, is to select one stone of the group, move it on a straight line over any friendly stones, and place it on the next empty cell. Even if a player may move more than one group, each group can only be moved once at each turn. Groups may split and join. If a group joins another group, the latter looses its right to movement. CAPTURE - A stone that looses its liberties (same as in Go), is replaced by a stone of the other color. Stones captured by dropping can move on the same turn; Stones captured by moving cannot move on the same turn. Suicide drops are allowed. ROSETTE - A ring of six connected stones around a gray hex is called a rosette. This structure is uncapturable. GOAL - Wins the player with more points. Points are rewarded to: One point for each stone; One point for each surrounded cell.

An example Black structure is safe. White cannot drop a stone at cell a6, since it is captured and turns black, creating a rosette. And he cannot move c4 to a2, and then drops at a6, since dropping must precede movement.