banner_gamerz.gif (6081 bytes)

Help For Hexbo

Introduction

Welcome to the network Hexbo server. The rules of Hexbo are below. The Hexbo "challenge" command is described here. Other commands are the same for all pbmserv games.

hexbo challenge [ -small | -beginner ] userid1 userid2 [ ... userid6 ]
Start a new game between userid1 and userid2
-small|-beginner allows player to play the smaller 9x9 board.

Hexbo supports games with two, three, or six players. Four or five players cannot play because there is not a fair and symmetrical starting position.

Hexbo Rules (Copyright (c) 1996 Mark Steere <tanbo@ix.netcom.com>)

AUTHOR'S NOTE: Feel free to distribute this document.

PREFACE

Hexbo, created by Richard Rognlie in February 1996, is a variant of Tanbo, invented by the author in October 1993. Hexbo substitutes a hexagonal board for the square board of Tanbo. Otherwise, the rules of Hexbo are identical to those of Tanbo. And this document is largely identical to "Tanbo Rules", except the diagrams have been changed to represent Hexbo.

         HEXBO                 TANBO     
       . . . . .         . . . . . . . . .
      . # . . O .        . # . . . . . O .
     . . . . . . .       . . . . . . . . .
    . . . . . . . .      . . . . . . . . .
   . O . . . . . # .     . . . . . . . . .
    . . . . . . . .      . . . . . . . . .
     . . . . . . .       . . . . . . . . .
      . # . . O .        . O . . . . . # .
       . . . . .         . . . . . . . . .

These small versions of Hexbo and Tanbo show the difference in board shape and pattern.

I   INTRODUCTION
II  RULES AND OBJECT

I  INTRODUCTION
===============

HEXBO IS A GAME OF ROOTS
------------------------
Hexbo crudely models a system of plant roots.  Roots which are
growing, competing for space, and dying.  In beginner play, the roots
grow much as the roots in a garden. Over time, the roots become shrewd
and calculating.

There is no score in Hexbo.  The object is to completely destroy your 
opponent.  

FIGURES A - D are excerpts from a novice game.  FIGURE A is the
initial configuration.  FIGURES B and C show roots growing and
competing for space.  In FIGURE D, black has won by eliminating the
six white roots.

  FIGURE A: INITIAL SETUP - 12 SEEDS
            #=BLACK, O=WHITE

                  1 2 3 4 5 6 7 8 9 10
                 / / / / / / / / / / 11
             A- # . . . . . . . . O / 12
            B- . . . . . . . . . . . / 13
           C- . . . . . . . . . . . . / 14
          D- . . . . . . . . . . . . . / 15
         E- . . . . O . . . . # . . . . / 16  
        F- . . . . . . . . . . . . . . . / 17 
       G- . . . . . . . . . . . . . . . . / 18
      H- . . . . . . . . . . . . . . . . . / 19
     J- . . . . . . . . . . . . . . . . . . /
    K- O . . . # . . . . . . . . . O . . . #  
     L- . . . . . . . . . . . . . . . . . .  
      M- . . . . . . . . . . . . . . . . .  
       N- . . . . . . . . . . . . . . . .  
        O- . . . . . . . . . . . . . . .    
         P- . . . . O . . . . # . . . .    
          Q- . . . . . . . . . . . . .     
           R- . . . . . . . . . . . .      
            S- . . . . . . . . . . .      
             T- # . . . . . . . . O    


  FIGURE B: ROOTS SPREAD VIA ADJACENCIES.  CLUMPS AND CLOSED LOOPS ARE
            NOT PERMITTED.

                  1 2 3 4 5 6 7 8 9 10
                 / / / / / / / / / / 11
             A- # . . . . . . . . O / 12
            B- . # . . . . . . # O . / 13
           C- . . # O O O . # # . O . / 14
          D- . . # O . . . # . # . . . / 15
         E- . . # . O O . # . # . . . . / 16  
        F- . . # . O . O O . # . . . . . / 17 
       G- # # # . . . . . . # . . . . . . / 18
      H- . O O O O . . . .>#<. . . . . . . / 19
     J- . O . . # O . . . . . . . . . . . . /
    K- O O . . # . . . . . . . . . O . . . #  
     L- . . . . . . . . . . . . . . . . . .  
      M- . . . . . . . . . . . . . . . . .  
       N- . . . . . . . . . . . . . . . .  
        O- . . . . . . . . . . . . . . .    
         P- . . . . O . . . . # . . . .    
          Q- . . . . . . . . . . . . .     
           R- . . . . . . . . . . . .      
            S- . . . . . . . . . . .      
             T- # . . . . . . . . O    


  FIGURE C: 12 ROOTS COMPETE FOR SPACE.  SEPARATE,
            LIKE-COLORED ROOTS MUST NOT BE JOINED.

                  1 2 3 4 5 6 7 8 9 10
                 / / / / / / / / / / 11
             A- # . . . O # . . . O / 12
            B- . # O . . O # . # O . / 13
           C- . . # O O O . # # . O O / 14
          D- . . # O . . . # . # O . O / 15
         E- . . # . O O . #>O<# . . # O / 16  
        F- . . # . O . O O O # . . # . O / 17 
       G- # # # . # O . # . # . # # O . . / 18
      H- . O O O O # O O # # . # O O . . # / 19
     J- . O . . # O # . # . # # . . O . . # /
    K- O O . # # O . # # O . . # O O # . . #  
     L- . O # . # O O O O . . # O . . # O .  
      M- . O # . . . . . O . # O . . # O .  
       N- . O # . O . . . O . . . . # O .  
        O- . O # # O . . # # . # # # . O    
         P- O # . . O . . . # # . O O O    
          Q- # . . . O O O O O O O . .     
           R- # O O O . . . . . . . .      
            S- O . . . . . . . . . .      
             T- . . . . O O O O O O    


  FIGURE D: BLACK WINS BY ELIMINATING THE 6 WHITE ROOTS.

                  1 2 3 4 5 6 7 8 9 10
                 / / / / / / / / / / 11
             A- . . . . . # # # # # / 12
            B- . . . . . # . . . . . / 13
           C- . . . . . # . # . . . . / 14
          D- . . . . . # . # . # # . # / 15
         E- . . . . . # . . # # . # # . / 16  
        F- . . . . # . # # . . . # . # . / 17 
       G- . . . . . # . . # # . # . . # . / 18
      H- . . . . . # . . # . # # . . . # # / 19
     J- . . # . # . # . # . . . . . . # . # /
    K- . . . # # . . # # . . . . . . # . . .  
     L- . . # . # . . . . . . . . # . # . .  
      M- . . # . # # # . . . . . # . # . .  
       N- . . # . . . # . . . . . # # . .  
        O- . . # # . . # . . . . # . # .    
         P- . # . # . . # # # # # . . .    
          Q- # . . # . . . . . . . . .     
           R- # . . . . . . . . . . .      
            S- . . . . . . . . . . .      
             T- . . . . . . . . . .    


II  RULES AND OBJECT
====================

EQUIPMENT
---------
Hexbo requires a board as shown in Figure A, as well as 150 white
stones and 150 black stones.  One player takes ownership of the white 
stones and becomes "white".  The other player is "black".  In the 
diagrams, white is "O" and black is "#".

INITIAL SETUP
-------------
Initially, each player has 6 stones on the board as shown in Figure A.
The stones are interspersed and evenly spaced on the board.

BASIC MOVES
-----------
After setting up this initial configuration, black makes the first
move.  (A "move" will always mean adding exactly one stone to the
board.  Stones are never actually moved from one point to another on
the board.)  Next white makes a move, and the players continue to take
turns adding their stones to the board until one player wins.

A newly added stone must "connect" to exactly one stone of the same
color, which is already on the board.  Two points "connect" if they
are adjacent.  Several examples of legal and illegal moves appear
in the following sections.

Players are not allowed to pass.  You must add exactly one stone to
the board during your turn.

  FIGURE E: EXAMPLES OF LEGAL AND ILLEGAL MOVES FOR WHITE.
  LEGAL WHITE MOVES: D3, B8, H1, H13
  ILLEGAL WHITE MOVES (NO CONNECTION): E3, G6, G15, L11
  ILLEGAL WHITE MOVES (2+ CONNECTIONS): D5, C11, H2, L2

                  1 2 3 4 5 6 7 8 9 10
                 / / / / / / / / / / 11
             A- # # . . . . . . . O / 12
            B- . . # # # . . . . O . / 13
           C- . . . O O # . . O O . . / 14
          D- . . . O . O # . . . . . . / 15
         E- # . . . O . O # . # # . . . / 16  
        F- O # . . . . . O # . . # . . . / 17 
       G- . O # . . . . . . . . . # # . . / 18
      H- . . O # . . . . . . . . . . . . . / 19
     J- . O O . # . . . . . . . . O . . . . /
    K- O O # # # . . . . . . . . . O O . . #  
     L- . # . . . . . . . . . . . O . . . .  
      M- . . . . . . . . . . . . . . . . .  
       N- . . . . . . . . . . . . . . . .  
        O- . . . . . . O O . . . . . . .    
         P- . . . . O O . . . # # . . .    
          Q- . . . O . O . . . . # # .     
           R- . O O . . O . . . # . .      
            S- . # # # # . . # # . O      
             T- # . . . # . O O O O    


LEGAL MOVES CONNECT TO EXACTLY ONE STONE OF THE SAME COLOR
----------------------------------------------------------
In FIGURE E, points D3, B8, H1, and H13 are examples of legal
moves for white.  Each of these moves connects to exactly one white
stone, already on the board.

ILLEGAL MOVES THAT DON'T CONNECT TO ANY STONES OF THE SAME COLOR
----------------------------------------------------------------
Points E3, G6, G15, and L11 are examples of illegal moves for white.
These moves don't connect to any white stones.

ILLEGAL MOVES THAT CONNECT TO 2 OR MORE STONES OF THE SAME COLOR
----------------------------------------------------------------
Points D5, C11, H2, and L2 in FIGURE E are examples of illegal
moves for white.  These moves are illegal for white because they each
connect to two or more white stones already on the board.

Point D5 for example is an illegal move for white because it connects
to five white stones.  The five white stones are below-left, left,
above-left, above-right, and right of point D5.

Point C11 is an illegal move for white because it connects to two
white stones already on the board.  The two white stones are left, 
and above-left of point C11.

ROOTS
-----
By adding stones in this manner, the players form "roots" (A root is a
group of interconnected stones of the same color.)  In FIGURE B, roots
are just beginning to form.  As the roots grow larger, they compete
for limited growing space.

After a few games, players can easily discern the individual roots.

When a single root becomes so constricted that it can no longer grow,
the entire root is immediately removed from the board.  The
surrounding roots can then grow into the area vacated by the removed
root.  (Sometimes two or more roots will run out of growing space
simultaneously.  This is discussed separately, in detail below.)

In FIGURE D, black has won the game by eliminating the six white
roots.  (See OBJECT OF THE GAME.)

  FIGURE F: IMPOSSIBLE FORMATIONS

                  1 2 3 4 5 6 7 8 9 10
                 / / / / / / / / / / 11
             A- # . . . . . . O . . / 12
            B- . # . . . . . . O O O / 13
           C- . # # . . . . . . . . . / 14
          D- . # # . . . . . . . . . . / 15
         E- . # # . . . . # # # # # . . / 16  
        F- # # # . . . . . . . # # # . . / 17 
       G- . . . # # . . . . . . # # # . . / 18
      H- . . . . . # # . . . . . . . . . . / 19
     J- . . # # . . . # . . . . . . . . . # /
    K- . . # . # . . . . . . . . . . . . # #  
     L- . . # # . . . . . . O . . . . . # #  
      M- . . . . . . . . . . . . . . . . .  
       N- . . . . . . . . . . . . . . . .  
        O- # # . . O O O . . . # # # # .    
         P- # . . O O O O . . # . . . #    
          Q- # . O O O O O . . # . . #     
           R- # . O O O O . . . # # #      
            S- # . O O O . . . . O O      
             T- # . . . . . . . . O    


IMPOSSIBLE FORMATIONS
---------------------
The rules for adding stones make it impossible for certain types of
formations to occur in Hexbo.  In particular, separate roots of the
same color will never be joined.  Roots will not form closed loops or
clumps.  Every root will contain one of the stones of the initial
configuration (shown in FIGURE A).  New roots will never be created
during the course of the game.

All of the formations in FIGURE F are impossible.  They cannot be
created without violating the rules of Hexbo.

THE EXPANDED ROOT
-----------------
When a player makes a move, he connects his newly added stone to only
one of his roots.  This root increases in size by one and is referred
to as the "expanded root" during the player's turn.

The "expanded root" concept is essential to an understanding of the
following sections.

ROOT SPACE
----------
The "root space" of a root consists of the available legal moves
which serve to expand that root.  A root is "free" if it has at least
one point of root space.  For example, in FIGURE E, point T15 is the
only point of root space for the small black root.  Because that root
has root space, it is free.

BOUNDED ROOTS
-------------
A root becomes "bounded" when a move is made which completely deprives
that root of root space.  For example, in FIGURE E, if white adds a
stone to point T15, white deprives the small black root of root space,
therefore bounding it.

Alternatively, white could bound one of his own roots by moving to
point H1 in FIGURE E.  Expanding this small white root would leave it
with no root space, therefore bounding it.

The "bounded root" concept is central to Hexbo.

REMOVING BOUNDED ROOTS
----------------------
When a player makes a move which causes one or more roots to become
bounded, he will be required to remove at least one of these bounded
roots from the board, during his current turn.  This is described in
detail in the following sections.

  FIGURE G:                    FIGURE H:
  ROOT IS EXPANDED             EXPANDED, BOUNDED ROOT
  AND BOUNDED.                 IS REMOVED.

             1 2 3 4 5                  1 2 3 4 5
            / / / / / 6                / / / / / 6
        A- . . . O . / 7           A- . . . O . / 7 
       B- . # # # O O / 8         B- . # # # O O / 8
      C- O # . . O . # / 9       C- O # . . O . # / 9
     D- O . . . # . . # /       D- O . . . # . . # /
    E- . O O . . # # # .       E- . O O . . # # # .
     F- O # O . # . . #         F- O . O . # . . #
      G- . # . O . O O           G- . . . O . O O
       H- . # # O O .             H- . . . O O .
        J->#<. O . .               J- . . O . .


EXPANDED AND BOUNDED ROOT IS REMOVED FROM THE BOARD
---------------------------------------------------
If you make a move which expands and bounds one of your roots, you
must immediately remove this expanded and bounded root from the board.
FIGURES G and H demonstrate such a move on a 9 by 9 board.  By moving
to point J5 in FIGURE G, black expands and bounds the small black root
in the lower left corner.  Black must immediately remove the expanded
and bounded root, as shown in FIGURE H.

  FIGURE I:                    FIGURE J:
  EXPANDED ROOT AND THREE      ONLY THE EXPANDED,
  OTHER ROOTS ARE BOUNDED.     BOUNDED ROOT IS REMOVED.

             1 2 3 4 5                  1 2 3 4 5
            / / / / / 6                / / / / / 6
        A- # . O . . / 7           A- . . O . . / 7 
       B- . # # O O . / 8         B- . . . O O . / 8
      C- O # . # . # # / 9       C- O . . . . # # / 9
     D- O # . . # . . # /       D- O . . . . . . # /
    E- . O # # .>#<. # O       E- . O . . . . . # O  
     F- . O . . . O O O         F- . O . . . O O O
      G- . O O # O . .           G- . O O # O . .
       H- O # # . O O             H- O # # . O O   
        J- # . # O .               J- # . # O .   

REMOVE ONLY THE EXPANDED, BOUNDED ROOT - NO OTHER ROOTS
-------------------------------------------------------
If your move expands and bounds one of your roots, and simultaneously
bounds one or more additional roots of either color, you must
immediately remove the expanded root, and only the expanded root.
You must not remove any additional roots during your current turn.
The additional roots, which are momentarily bounded during your turn,
become free again when you remove the expanded root.

FIGURES I and J demonstrate such a move.  By moving to point E6 in
FIGURE I, black expands the black root in the center.  This move
simultaneously bounds four roots: the expanded root, the black
root in the lower left corner, the black root on the right,
and the white root in the lower right corner.  Black must immediately
remove the expanded root, and only the expanded root, as shown in 
FIGURE J.

Three roots in FIGURE J, which were momentarily bounded during black's
turn, became free again when black removed the expanded, bounded root.
The white root in the lower right corner reclaimed its one point of
root space.  The two remaining black roots also reclaimed their
root space.

At the conclusion of a turn, there should not be any bounded roots on
the board.

  FIGURE K:                    FIGURE L:
  EXPANDED ROOT IS NOT         REMOVE THE THREE
  BOUNDED, BUT THREE OTHER     BOUNDED ROOTS.
  ROOTS ARE BOUNDED.

             1 2 3 4 5                  1 2 3 4 5
            / / / / / 6                / / / / / 6
        A- . . O . . / 7           A- . . O . . / 7 
       B- . # # O O . / 8         B- . # # O O . / 8
      C- O # . # . # # / 9       C- O # . # . . . / 9
     D- O # . . # . . # /       D- O # . . # . . . /
    E- . O # # .>#<. # O       E- . O # # . # . . .  
     F- . O . . . O O O         F- . O . . . . . .
      G- . O O # O . .           G- . O O . . . .
       H- O # # . O O             H- O . . . . .   
        J- # . # O .               J- . . . . .   

IF ONE OR MORE ROOTS GET BOUNDED, AND THE EXPANDED ROOT IS
----------------------------------------------------------
NOT ONE OF THE BOUNDED ROOTS, REMOVE ALL THE BOUNDED ROOTS.
-----------------------------------------------------------
If you move to bound one or more roots of either or both colors, and
the expanded root is not one of the bounded roots, you must
immediately remove all of the roots which you bounded by making that
move.

By moving to point E6 in FIGURE K, black expands the black root in the 
center.  Unlike the previous example, this time the expanded root is 
not bounded.  However, three other roots are bounded by this move: the 
black root in the lower left corner, the black root on the right, and 
the white root in the lower right corner.  Black must immediately 
remove the three bounded roots, as shown in FIGURE L.

SUMMARY - WHEN TO REMOVE ROOTS
------------------------------
In summary, whenever a move causes a single root to be bounded, that
root is immediately removed.  When a player's move causes two or more
roots to be simultaneously bounded, the player must look at the
expanded root.

If the expanded root is one of the bounded roots, then the expanded
root, and only the expanded root is removed.

Otherwise, if the expanded root is not one of the bounded roots, then
all of the bounded roots must be removed.

The rules for removing roots were designed to ensure that when all
six of a player's roots have been eliminated, the other player will
still have at least one root remaining on the board.  This prevents
ties (draws) from occuring.

RETURN OPPOSING ROOTS TO OPPONENT
---------------------------------
Whenever you remove an opposing root from the board, you must return
its stones to your opponent.  Players never take ownership of opposing
stones.  After stones have been returned to their owner, they can be
played again during later turns.

OBJECT OF THE GAME
------------------
To win, a player must eliminate all six of his opponent's roots.
One player will always win.  It's impossible to repeat a board
configuration in Hexbo.  Therefore a game cannot result in a draw.

  FIGURE M:                    FIGURE N:
  LAST MOVE OF THE GAME.       WHITE HAS WON THE GAME.
  BLACK MUST SACRIFICE
  HIS LAST REMAINING ROOT.

             1 2 3 4 5                  1 2 3 4 5
            / / / / / 6                / / / / / 6
        A- # . O . O / 7           A- . . O . O / 7 
       B- . # # O O # / 8         B- . . . O O . / 8
      C- O # . # . O # / 9       C- O . . . . O . / 9
     D- O # . O # . # . /       D- O . . O . . . . /
    E- . O # # O # # .>#<      E- . O . . O . . . . 
     F- . O . # O . # #         F- . O . . O . . . 
      G- . O O O # # .           G- . O O O . . .
       H- O . . O . #             H- O . . O . .    
        J- O O . O O               J- O O . O O     

FIGURES M and N show the last turn of a game.  In FIGURE M, black
has one root remaining on the board.  Black's only available
move is point E9, and point E9 is also the black root's only remaining
point of root space. By moving to point E9, black bounds his last
remaining root which he immediately removes from the board, as shown
in FIGURE N. White has won the game.

 

apac
he_pb.gif (2326 bytes)