Medusa is a Go game played on a base-10 hexboard with 61 'holes', so that a corner cell has 2 liberties, a cell on the edge 3, and a cell on the inside 4, as in regular Go. On each turn a player 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. The player with more points wins. Points awarded: One point for each stone. One point for each surrounded cell.