From: hansb@cs.ruu.nl (Hans Bodlaender)
Subject: Star Trek Chess
Date: Thu, 12 Nov 1992 15:59:25 GMT
Organization: Utrecht University, Dept. of Computer Science
Keywords: here are the rules - repost

Here are the rules of 3D-chess. This is a repost of something already very
long ago posted on the newsnet. Have fun. This is the variant where captain
Kirk always wins from Spock. (Or did he ever lose in an episode of Star Trek?)
Enjoy!
			     Hans Bodlaender, Utrecht, the Netherlands

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    3D chess is a very interesting game. I have recently constructed a *board*  
from the details given in the _Starfleet_Technical_Reference_Manual_ (the last 
appedix, I can't remember the letter). It is a very simple game to learn. The 
movement of the pieces follows the same rules as in 2D chess only with 3D 
freedom of movement.


    The chessboard consist of three 4x4 square *levels* and four 2x2 square 
*movable* levels (yes, movable). The fixed levels are arranges in a staircase 
fashion with the last two rows of one level positioned directly under the 
first two rows of the next. Here is a rough diagram showing the setup:



                     side view                __ __  <- movable
                                                |          level
                                     __ __ __ __|   
                                                
                                                  
                               __ __ __ __     <- fixed
       movable   ->   __ __                         levels
         levels         |                   
                        |__ __ __ __     
        top view      __ __                   __ __
                     |b_|w_|__ __ __ __ __ __|b_|w_|    <-movable
   b-black square    |w_|b_|w_|b_|w_|b_|w_|b_|w_|b_|        level
   w-white square       |w_|b_|w_|b_|w_|b_|w_|b_|
                      __|b_|w_|b_|w_|b_|w_|b_|w_|__
                     |b_|w_|b_|w_|b_|w_|b_|w_|b_|w_|
                     |w_|b_|                 |w_|b_|


    As one can see the four movable levels are positioned at the far corners 
of the first and third fixed levels. This is the starting position for the 
levels. The pieces one the board are initially arranged as follows:
 (the mv-lvls are detacted for clarity)

K - W king                                                 k - B king
Q - W queen      __ __                             __ __   q - B queen
R - W rook      |R_|P_|  __ __ __ __ __ __ __ __  |p_|r_|  r - B rook
N - W knight    |N_|P_| |B_|P_|__|__|__|__|p_|b_| |p_|n_|  n - B knight
B - W bishop            |Q_|P_|__|__|__|__|p_|q_|          b - B bishop
P - W pawn       __ __  |K_|P_|__|__|__|__|p_|k_|  __ __   p - B pawn
                |N_|P_| |B_|P_|__|__|__|__|p_|b_| |p_|n_|
                |R_|P_|                           |p_|r_|
-MOVABLE LEVELS -
    Each of the movable levels can occupy any corner of one of the three fixed
levels and oriented either up or down:

                                     __ __ 
                                       |
                            __ __ __ __|
                                       |
                                     __|__ 
     
    This distinction allows for two mv-lvls to occupy the same corner as long 
as one is oriented up and the other down. 
    The alternating b/w color pattern is consistant through each fixed and 
movable level, i. e., a black square is always directly under a blcak square 
and a white square is always directly under a white square.
    
    The rules governing the movement of mv-lvls are as follows: 
  
    A mv-lvl may be moved by either player only if the mv-lvl is not occupied 
      by any pieces.

    A mv-lvl may only be moved if it is empty *or* if it holds only *one* pawn 
      of the *same* color as the player who wishes to move it.

    A mv-lvl may only be made to orient down (or up) if it is not occupied and 
      if the down (or up) position is not already occupied by another mv-lvl.
    
    A mv-lvl may only be moved to an ajacent(sp?) corner of the same fx-lvl or 
      inverted and moved to an ajacent(sp?) corner of the next high or next 
      lower fx-lvl:
                                                      mv - mv-lvl 
            n                                          n - possible new
             __ __ __ __  mv   n            mv               position
            |__|__|__|__|        __ __ __ __ 
            |__|__|__|__|                   n        Movement
            |__|__|__|__|                            will work either
            |__|__|__|__|                            direction
                          n                            (mv -> n or n -> mv)


                                 n
                                  __ __ __ __ 
                                mv           n
                                       n
                            __ __ __ __ 
                                    
    The movement, inversion, or inversion and change mv-vl all count as a 
      single move just as the movement of a piece counts as a single move, 
      i.e., you can move a mv-lvl(if can) or you can move a piece(if can).

    Notice the changing of a fx-lvl requires an inversion which requires 
      that the mv-lvl be unoccupied!


-MOVEMENT OF PIECES-
    The movement of pieces follow the same patterns as they do in standard 
chess. To determine whether or not a piece may move to a given square in 3D 
chess depends on two factors(other than- Is the square occupied?).
    
    First one must look at the position of the piece on the board from the 
"bird's eye" point of perspective. If one were to treat this view as flat, the 
piece in question could move to any valid square within the limits of its 
2D chess movement constraints.(diagonally only, forward only, etc.)
    Second, since this is a 3D board the movement must meet a second 
condition. The piece may only move to the square in question if a 3d path can 
be found such that each square the piece passes through is both unoccupied 
(except of course when moving a knight) and exist, i. e. there is an 
intervening(sp?) mv-lvl or the square is on a fx-lvl.
    Notice the word intervening(besides sp). This means that a piece may only 
moved to a new fx-lvl if and only if the is a mv-lvl in its path.
Observe the diagram:

  r- B rook                  x_ r_ x_ x_   <=fx-lvl
  x- possible               |                 __ __ __ __ __ __ 
      positions           x_ x_  <=mv-lvl    |__|__|__|x_|__|__|
                                             |__|__|__|x_|__|__|
           fx-lvl=>    x_ x_ x_ __           |__|__|__|x_|__|__|
                                             |x_|x_|x_|r_|x_|x_|
                                                |__|__|

  This can lead to some interesting moves: 

  r- B rook                   __ __ __ __     __ __ __ __ __ __ 
  x- new                     |               |__|__|__|__|__|__|
      position             __|g_             |__|__|__|__|__|__|
  t- path                                    |__|__|__|__|__|__|
  P- W pawn             __ x_ P_ r_          |__|x_|Pg|r_|__|__|
                                                |__|__|

 The rook "jumped over" the pawn.


    General notes-
    
    One will notice that when playing 3D chess it will take a considerable 
amount of time just to move to the neutral level(the fx-lvls are referred to 
as the white, neutral, and black levels -- the lower, middle, and upper 
respectivly), in fact longer for black(can the reader guess why?). But after 
that phase of the game is reached the game can become very complex, very 
quickly. After a few games one can see how 3D chess can improve starship 
tactics and inspire three-dimensional thinking (Khan's deficiency and 
undoing).

    Though of course the hardest thing about 3D chess I have found (next to 
finding a board- I build mine) is finding players. That is why I am posting 
this in both rec.arts.startrek and rec.games.chess. 

    I would welcome any takers not to mention suggustions for a standardized 
notation for 3d chess- for record purposes and/or 3dchess by mail.

    Most of this I had to deduce out of what was inferred in the _Tech_Man_. 
They didn't mention specifics on some movement possiblities and left alot up 
to interpretation. If any one else has read the _Tech_Man_ section I would 
welcome comments in rec.games.chess.

==============================================================================
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   useful thing a        |   "He's dead  |    undgrad n Astronomy
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