GYGES

Copyright (c) 1984 Claude Leroy

This game is played on the following 8x6 board:

Each player starts with 6 pieces off board: two singles, two doubles and two triples. 

  • SETUP - Each player places his 6 pieces on his second row.
  • TURN - On each turn, each player must move one of the pieces that are in his closest row (that row is called the shore). 
    • The pieces don't belong to either player. They are shared and may be moved by both players.
    • A single moves one cell, a double moves two cells and a triple moves three cells. 
    • The movement must be orthogonally sideway or forward thru empty cells (no jumps) except the last cell that may be occupied. In that case, the player must do one of two actions:
    • BOUNCE -  The piece occupying that cell is bounced, i.e., the player must move it (which may produce another bouncing and so on...). 
      • If a bouncing piece cannot move, all the move sequence is invalid.
      • Within a bouncing sequence, the player cannot use the same cell twice.
    • RELOCATE - The piece occupying that cell is placed on any empty cell behind the opponent's shore.
    • A player with no valid moves must pass.
    • The first/last rows cannot be used in a moving sequence (except as the last cell move which wins the game)
    • KO - A move cannot repeat the previous board position.
  • GOAL - Wins the player that moves one piece to the opponent's first row.

An example

North's turn. North must move the triple at a6 (the only piece on his shore). However he can win with the following bouncing sequence: a6-c5-c4-a4-a3-b1 (this last one must be a3-b3-b2-b1 and not a3-a2-a1-b1 which is invalid because the last row was used during the move sequence and not only in the last move to win).

More information about Gyges could be found here before the link went dead around 2004. Here's the original text:

Here are the rules of a very unknown abstract game called Gyges. I've just
translated them from french, the author of this game is actually Claude Leroy
(http://jeuxsoc.free.fr/g/gyges.htm).

It would be nice to play this game on Richard's Play-By-eMail Server in the
future. I would be more than happy to write the needed code, even (I'm a
computer science engineer when I'm not playing games *grin*), preferably
under a Free Software license, so if you're interested...

	Agt the Walker.


Help for Gyges

Introduction

   Welcome to the network Gyges server. The rules of Gyges are below.
   The commands are the same for all pbmserv games.

Rules of Gyges

   Copyright (c) 1984 Claude Leroy (http://jeuxsoc.free.fr/g/gyges.htm).
   All rights reserved. Here they have been translated from french, I
   hope Claude or his current editor won't mind...

Starting the Game

   The two players, "South" and "North", each receive 6 rings (2 singles
   or aces, 2 doubles, 2 triples). "South", then "North", place their 6
   rings *in any order* on their respective starting row.

                        N               -> "North" goal
                   . . . . . .          -> "North" starting row
                   . . . . . .
                   . . . . . .
                   . . . . . .
                   . . . . . .
                   . . . . . .          -> "South" starting row
                        S               -> "South" goal

   Each slot on the 6x6 board is orthogonally connected to their
   immediate neighbors (like a Go board). Each player's goal is connected
   to every slot of their starting row.

   The game is won by landing any ring on your opponent's goal.

Movement Rules

   On your turn ("South" starts), you move a ring from slot to slot by
   following the connections. A single ring can only move through one
   connection, a double ring through two (different) connections (i.e.
   one empty slot), and a triple ring through three different connections
   (i.e. two empty slots).

   For instance (X is a possible move, . an empty slot):

         X               X                 X               or like this:
       X 1 X           X . X             X . X
         X           X . 2 . X         X . . . X           3 .     X .
                       X . X         X . . 3 . . X         X .     3 .
                         X             X . . . X
                                         X . X             . 3     . X
                                           X               . X     . 3

Recognizing your Rings

   There are no "white" or "black" pieces, like in Chess or Go for
   instance. Actually, you can only play your "proximes", i.e. the rings
   on the closest row from your goal. That particular row is called
   "shore".
   
                   1 2 3 4 5 6

                        N
                   . 3 . . . .     6
                   . . 2 1 . .     5
                   . 2 1 2 3 .     4
                   . 1 1 3 2 .     3
                   . . . . . .     2
                   . . . . . 3     1
                        S

   On that diagram, the shores are still the starting rows (1 and 6).
   Therefore North and South can only play one triple ring each. If South
   plays 16-46 and North plays 62-41, then the shores become rows 3 and
   5.

Bouncing

   Indeed, your move can use other rings, that is if your ring lands on
   another ring at the end of its movement, then it can borrow that other
   ring's movement, and so on.

                   1 2 3 4 5 6

                        N
                   . . . . . .     6
                   3 . . . . .     5
                   . . 1 . 1 .     4
                   1 . 2 3 . 3     3
                   3 . 2 2 . 1     2
                   . . . . 2 .     1
                        S

   Here North can reach South's goal (therefore win) by playing
   51-43-33-31-21-(11-12-)S. South playing before North can ward off that
   threat by playing 15-26-36-66, which becomes North's new proxime (her
   shore is now row 6).

Eurydice's Taboo

   Whether your move includes bounces or not, you cannot use the same
   connection several times... but you can reuse the same slot ! 

                   1 2 3 4 5 6

                        N
                   . . . . . .     6
                   1 . . . . .     5
                   3 . 2 3 . .     4
                   3 . 2 1 1 .     3
                   2 . 1 3 2 .     2
                   . . . . . .     1
                        S

   For instance, North's ace cannot win by 51-41-31-21-S since the 31-32
   connection would be used twice: 51-41-(42-32-)31-(32-22-)21-(11-)S.
   Whereas South can win by 24-(14-15-)25-(24-)34-44-(54-64-)N although
   slot 24 is visited twice.

The Goal

   You cannot go past either goal, and your goal can only be the
   destination of your opponent's last move.

Relocation

   Instead of bouncing on another ring, you can put your ring there and
   relocate that other ring anywhere but past your opponent's shore.

    1 2 3 4 5 6               1 2 3 4 5 6               1 2 3 4 5 6      
                                                                         
         N                         N                         N
    2 1 3 1 3 2     6         2 1 3 1 3 2     6         2 1 3 . 3 2     6
    . . . . . .     5         . . . . . .     5         . . . . . .     5
    . . . . . .     4   --\   . . . 2 . .     4   --\   . . . 1 . .     4
    . . . . . .     3   --/   . . . . . .     3   --/   . . . 2 . .     3
    . . . . . .     2         . . . . . .     2         . . . . . .     2
    1 1 3 2 2 3     1         1 1 . 3 2 3     1         1 1 . 3 2 3     1
         S                         S                         S

   For instance, from the starting position above, South can play
   13x14=44, which means that instead of bouncing the triple (originally
   at 13) at 14, you put it there and relocate the double (originally at
   14) to 44, which threatens 14-44-64-N. North can then ward off the
   threat by playing (for instance) 64x44=34, which also prevents South
   from reaching the two rings in the middle in her next move.

Renop Law ("repetita non placent")

   You cannot play a move reproducing an anterior position.

Stalemating

   When a player cannot play anymore (no legal moves), her opponent keeps
   moving till winning or till the stalemated player can play again:
   whichever event happens first.

                   1 2 3 4 5 6

                        N
                   . 3 . 3 . 3     6
                   1 1 2 2 3 2     5
                   . . . 1 . .     4
                   . . . 1 . 2     3
                   . . . . . .     2
                   . . . . . .     1
                        S

   Here North is stalemated, therefore South can win by 34-44-43; (here
   North is still stalemated) 43-53-N.

Gyges Notation

   Here is a sample game:

   South                        North
   1 231123                     2 321123
   3 16-35                      4 61-53
   5 15-24                      6 66x65=21
   7 13-14-24x35=33             8 62x53=36
   9 14-24-35x36=43            10 64-54
  11 12-33x54=14               12 65-35x36=34
  13 Resign

   Because, for instance:
  13 14-24-35-36-66            14 63-64
  15 11-22                     16 64-54-35-36-S
   
        N             N             N             N             N
   3 2 1 1 2 3   . 2 1 1 2 3   . 2 1 1 3 .   . . 1 1 3 .   . . 1 . 3 .
   . . . . . .   . . 3 . . .   . . 3 . . .   . . 2 . . .   . . 2 1 . .
   . . . . . .   . . . . . .   . . . . . .   . . . . . .   . . 3 . . .
   . . . . . .   . . . . 3 .   . . . . 3 .   . . 3 . 1 3   . . 3 . 1 1
   . . . . . .   . . . . . .   2 . . 2 . .   2 . . 2 . .   2 . . 2 . .
   2 3 1 1 2 3   2 3 1 1 2 .   2 3 1 1 . .   2 3 . 1 . .   2 3 . . . .
        S             S             S             S             S

        N             N             N
   . . 1 . . .   . . . 1 . 1   . . . . . 1
   . . 2 3 . .   . . 2 3 . .   . . 2 3 . .
   . . 3 . . .   . . 3 . . .   . . 3 . . .
   . . 3 1 1 3   . . 3 1 1 3   . . 3 1 1 3
   2 . . 2 . .   2 . . 2 . .   2 2 . 2 . .
   2 . . 1 . .   2 . . . . .   . . . . . .
        S             S             1

   To play several moves in a row (stalemated opponent), split your moves
   with a semi-colon. For instance: 34-44-43; 43-53-N