Medusa

Alternate Names

No. of Players

Two

Equipment

History

Medusa was invented by Christian Freeling and published on the internet.

Objective

The objective of both players is to score more points than their opponent. Points are scored primarily by territory and territory is calculated at the end of the game by adding a player’s friendly stones on the board to their surrounded territory. A player’s Komi is also added to their points. In this game a white gains three points of Komi for going second and a player also earns one point of Komi for each time they pass when it is their turn to play.

Play

The game commences with the board empty of counters. The game follows many of the same rules of Go displaced to hexagonal board, especially in regards to Liberties, Ko, Komi, Seki and Atari. With black making the first move, alternate turns entail one of four options for a player:

  1. The placement of a single friendly stone on one of the hexagonal cells.

  2. The movement of one or more groups of friendly stones. A group is a set of two or more connected stones. More specifically, movement of a group of stones entails taking a single one of its stones and moving it in a straight line over any number of friendly stones in an unbroken row, to land on the first vacant cell beyond. No group may move more than once per turn. Groups may split or join to other groups in movement. If a group moves to contact a friendly group that has not yet moved itself, the latter therewith loses its right to move in that turn. Thus the order of moving groups may make a difference.

  3. A combination of the above. A player may place a stone and move a group. If doing so the placement of the new stone must precede the movement of the group.

  4. Passing. Each time a player passes and does not make a play it earns them one point of Komi.

Capturing is similar to Go and even more so to Lotus. A single stone or group of stones that has lost its last liberty is captured and reversed immediately to show its opponent’s color. As in Go, a single stone or group of stones that has one single liberty left is said to be in Atari. This game features a special condition that allows a player to form a rosette, which is filling, with friendly stones, the six cells surrounding a hole on the board, thus granting it a liberty. Any stone that is part of a group that has made such a formation cannot be captured. Capture may result from placement, movement or both. If a capture is the result of placement only, the stones are reversed before the movement phase. Thus the group resulting from the capture has the right to move in the same turn. Groups captured by movement contain at least one stone that has moved, and may not move in the same turn. If placement results in one or more of the opponent's groups losing their last liberty, they are captured whether or not the stone placed has any liberties itself at the time of placement. Suicide is legal in Medusa, and if placement results in losing one's own last liberty without killing any opponent's group, the placement is suicidal and the player's own stone or group is reversed before the movement phase.

The concept of Seki, shared territory, is carried over from the game of Go.

Strategy

Variations

Medusa is largely inspired by Rosette, a game invented in 1975 by Mark Berger.

Sources

  1. Schmittberger, R. Wayne. New Rules for Classic Games. John Wiley & Sons, Inc. New York, 1992. ISBN 0-471-53621-0

  2. Medusa at Sensei's Library. http://senseis.xmp.net/?Medusa