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Rules for 3-D Chess

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Origin of the Rules

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Rules for Tri-Dimensional Chess

Preface

These rules are intended for the private use of visitors to this website. Reproducing these rules in any manner whatsoever for the purposes of obtaining a profit is expressly prohibited.

These rules are not intended to cover all possible situations that may arise during a game. Where cases are not precisely addressed by any Section contained herein, it should be possible to reach a correct decision by studying analogous situations that are presented.

In the Sections that follow, "he", "him" and "his" can be substituted with "she", "her" and "hers," respectively.


Section 1: The Chessboard

The game of chess is played between two opponents by moving pieces on a 
series of square boards collectively referred to as a "chessboard".

 1.1  The chessboard is composed of 64 equal squares (the same number of 
      squares found on a conventional chessboard), with alternating light 
      ("white") and dark ("black") squares.  These squares are divided among 
      seven individual boards, three of which are at fixed positions and 
      four are movable.

 1.2  The three fixed boards are four squares by four squares and are
      permanently affixed to a stand so that the boards are arranged in a
      stair-step fashion with a common vertical distance between each level
      and each level offset by two ranks of squares.

 1.3  The lowest fixed level is called White's Board.

 1.4  The middle level is called the Neutral Board.

 1.5  The top level is called Black's Board.

 1.6  Each fixed board has two pins at each corner of the board, one
      projecting upward from the top surface of the board and one
      projecting downward from the bottom surface. These pins are used to
      attach the remaining four boards (generally referred to as attack
      boards) to the fixed boards.

 1.7  Each attack board is two squares by two squares and is mounted on
      a post equal in length to 1/2 the distance between the fixed levels,
      minus 1/2 the thickness of the attack board. Individual attack boards
      are named according to their starting position (see Section 1.8 and
      2.1).

 1.8  The starting positions of the attack boards are on pins located at
      the outermost corners of the upper and lower level with White's
      attack boards below White's Board, and Black's attack boards above
      Black's Board. When an attack board is placed on any given pin, one
      square on the attack board will be directly over or under a corner
      square of the fixed level to which it is attached. The attack board
      must always be oriented so that the color of this square matches the
      color of the square it overlaps.

 1.9  Each player has limited control over the movement of the two attack
      boards that begin the game on his side of the chessboard (see
      Section 5.1 and Section 7).

 1.10 The chessboard is placed between the players in such a way that
      the near corner to the right of each player is light ("white").

 1.11 Rows of squares or pins running lengthwise between the players are
      called "files".

 1.12 Horizontal rows of squares or pins at right angles to the files are
      called "ranks".

 1.13 The lines of like-colored squares at 45 degree angles to the files
      are called "diagonals".


Section 2: Notation

Notation is used as an aid in explaining and interpreting these rules
as well as for recording games and playing games by correspondence.

 2.1  The individual boards comprising the chessboard are identified as
      follows:
      WB - White's Board
      NB - Neutral Board
      BB - Black's Board
      KL - White's attack board that, at the start of the game, is located
           on the King's side of the Board (a.k.a. "King's Level").
      kl - Black's attack board that, at the start of the game, is located
           on the King's side of the Board.
      QL - White's attack board that, at the start of the game, is located
           on the Queen's side of the Board (a.k.a. "Queen's Level")
      ql - Black's attack board that, at the start of the game, is located
           on the Queen's side of the Board.

 2.2  The squares are identified as follows:
      The files are lettered from "a" to "f" from White's left to right, and
      the ranks are numbered from "1" to "10" from White to Black. By
      combining the file letter with the rank number, a square's two
      dimensional location can be specified. See Figure 1. However, since
      there are overlapping squares, it is usually necessary to include the
      board notation (See Section 2.1) as a suffix to the square notation
      (example: b4,WB). The recommended practice is to always include the
      board notation. The notation for fixed-board squares is constant, but
      the notation for attack board squares is dependent upon the attack
      board's location. Example: When QL is positioned at QP1 (see Section
      2.3), its square notations are a1,QL; b1,QL; a2,QL and b2,QL. But if
      this board is moved to QP3, its square notations become a5,QL; b5,QL;
      a6,QL and b6,QL.

 2.3  The pins on the fixed boards are identified as follows:
      KPn or QPn, where KP indicates a pin on the King's side of the board
      and QP indicates a Queen-side pin; and where n indicates a specific
      pin, the ranks of pins being numbered 1 through 12 from White to
      Black with downward projecting pins always odd, and pins on any given
      board numbered consecutively. See Figure 2.

 2.4  Moves are described:
      (a) in the case of a piece being transferred to a vacant square
      without capturing another piece (see Section 6.6(c) for "en passant"
      captures), by specifying the starting square's notation, followed by a
      dash (-), followed by the ending square's notation;
      (b) in the case of a piece making a capture, by specifying the
      starting square's notation, followed by the letter x, followed by the
      ending square's notation;
      (c) in the case of an attack board being transferred to a vacant pin,
      by specifying the starting pin's notation, followed by a dash (-),
      followed by the ending square's notation;
      (d) in the case of an attack board being rotated (see Section 7.2),
      by specifying its pin notation, followed by the letter r.


Section 3: The Pieces

 3.1 At the beginning of the game, one player has 16 light-colored
     ("white") pieces, the other has 16 dark-colored ("black") pieces. Each
      player has the following types (and quantities) of pieces:
      King   (1)
      Queen  (1)
      Rook   (2)
      Knight (2)
      Bishop (2)
      Pawn   (8)

 3.2  The initial arrangement of the pieces on the chessboard is shown
      in Figure 3.


Section 4: The Right To Move

 4.1  The player with the white pieces commences the game. The players
      alternate in making one move at a time until the game is completed. 

 4.2  A player is said to "have the move" when his opponent's move 
      has been completed.


Section 5: The General Definition Of The Move

 5.1  A move is:
      (a) the transfer by a player of one of his pieces from its current
          square to another square, which is either vacant or occupied by
          an opponent's piece.
      (b) the transfer by a player of one of his unoccupied attack boards
          from its current pin to an adjacent vacant pin.
      (c) the 180 degree rotation by a player of one of his attack boards
          which is occupied by one or more pieces of either or both
          players.

 5.2  A piece played to a square occupied by an opponent's piece captures
      it as part of the same move. The captured piece must be removed
      immediately from the chessboard by the player making the capture
      (see Section 6.6(c) for capturing "en passant").

 5.3  No piece, except the Knight (Section 6.5), may cross a square
      occupied by another piece. However, as part of any piece's move (as
      defined in Section 6), it has complete freedom of movement between
      boards as it progresses from square to square.


Section 6: The Moves Of The Pieces

For the moves described below, consecutive squares are defined as any
two squares whose notation (see Section 2.2) follows a logical
alphabetical progression (in the case of ranks), numerical progression
(in the case of files) or alphabetical and numerical progression
(in the case of diagonals), regardless of the board(s) on which the
squares are located. Example: b5,WB and b6,BB are consecutive squares;
but a2,QL and a9,ql are not; nor are b5,WB and b5,NB. See Figure 4.

 6.1  The King.
      The king moves to any consecutive square that is not attacked by an
      opponent's piece.
     
 6.2  The Queen.
      The queen moves along a path of consecutive squares to any square
      (except as limited by Section 5.3) on the file, rank, or diagonals
      on which it stands.

 6.3  The Rook.
      The rook moves along a path of consecutive squares to any square
      (except as limited by Section 5.3) on the file or rank on which it
      stands.

 6.4  The Bishop.
      The bishop moves along a path of consecutive squares to any square
      (except as limited by Section 5.3) on the diagonals on which it
      stands.

 6.5  The Knight.
      The knight's move is composed of two different steps; first, it makes
      one step of one single consecutive square along its rank or file, and
      then, still moving away from the square of departure, one step of one
      single consecutive square on a diagonal. It does not matter if the
      square of the first step is occupied.

 6.6  The Pawn.
      (a) The pawn may move only forward (except as limited by Section
          5.3).
      (b) Except when making a capture, it advances from its original
          square either one or two vacant consecutive squares along its
          file, and on subsequent moves it advances one vacant consecutive
          square along its file. When capturing, it advances one
          consecutive square along either of the diagonals on which it
          stands.
      (c) A pawn attacking a square crossed by an opponent's pawn which has
          just been advanced two ranks in one move from its original
          square may capture this opponent's pawn as though the latter had
          been advanced only one rank. This capture may only be made in
          immediate reply to such an advance and is called an "en passant"
          capture. The player making the capture may place his pawn on
          either level within the limits specified in Section 5.1(a).
      (d) On reaching his opponent's final fixed-board rank, a pawn must
          immediately be exchanged, as part of the same move, for a queen,
          a rook, a bishop, or a knight, of the same color as the pawn, at
          the player's choice and without taking into account the other
          pieces still remaining on the chessboard. This exchange of a pawn
          for another piece is called "promotion", and the effect of the
          promoted piece is immediate.


Section 7: The Moves Of The Attack Boards

 7.1  An unoccupied attack board moves to any adjacent vacant pin, with
      adjacent pins defined as:
      (a) two rank pins projecting from the same surface of the same board;
      (b) two file pins projecting from the same surface of the same board;
      (c) the two pins at the same corner of the same board;
      (d) two facing pins at the same corner of two different adjacent
          fixed boards;
      (e) two facing pins at different corners but on the same (king or
          queen) side of two different adjacent fixed boards.
      Example: Pins adjacent to KP5 are QP5, KP7, KP6, KP2 and KP4. Pins
      adjacent to KP1 are QP1, KP3 and KP2. See Figure 2.

 7.2  An occupied attack board rotates 180 degrees.


Section 8: The Completion Of The Move

  A move is completed:

 8.1  in the case of the transfer of a piece to a vacant square, when the
      player's hand has released the piece;

 8.2  in the case of a capture, when the captured piece has been removed
      from the chessboard and the player, having placed his own piece on
      its new square, has released the capturing piece from his hand;

 8.3  in the case of the promotion of a pawn, when the pawn has been
      removed from the chessboard and the player's hand has released the
      new piece after placing it on the promotion square. If the player
      has released from his hand the pawn that has reached the promotion
      square, the move is not yet completed, but the player no longer has
      the right to play the pawn to another square;

 8.4  in the case of the transfer of an attack board to another pin, when
      the player's hand has released the attack board;

 8.5  in the case of the 180 degree rotation of an attack board, when the
      player's hand has released the attack board.


Section 9: Illegal Positions

 9.1  If, during a game, it is found that an illegal move was made, the
      position shall be reinstated to what it was before the illegal move
      was made. The game shall then continue by applying the rules of
      Section 8 to the move replacing the illegal move. If the position
      cannot be reinstated, the game shall be annulled.

 9.2  If, during a game, one or more pieces or attack boards have been
      accidentally displaced and incorrectly replaced, the position before
      the displacement occurred shall be reinstated, and the game shall
      continue. If the position cannot be reinstated, the game shall be
      annulled.

 9.3  If a player moves and in the course of this inadvertently knocks
      over a piece, or several pieces, or disorients an attack board, he
      must re-establish their positions.

 9.4  If, after an adjournment, the position is incorrectly set up, the
      position as it was on adjournment must be set up again and the game
      continued.

 9.5  If, during a game, it is found that the initial position of the
      pieces or attack boards was incorrect, the game shall be annulled.


Section 10: Check

10.1  The king is in "check" when the square it occupies is attacked by one
      or more of the opponent's pieces; in this case, the latter is/are
      said to be "checking" the king. A player may not make a move which
      leaves his king on a square attacked by any of his opponent's
      pieces.

10.2  Check must be parried by the move immediately following. If any check
      cannot be parried, the king is said to be "checkmated" ("mated").

10.3  Declaring a check is not obligatory.


Section 11: The Completed Game

11.1  The game is won by the player who has checkmated his opponent's king.
      This immediately ends the game.

11.2  The game is won by the player whose opponent declares he resigns.
      This immediately ends the game.

11.3  The game is drawn when the king of the player who has the move is
      not in check, and this player cannot make any legal move. The
      player's king is then said to be "stalemated". This immediately ends
      the game.

11.4  The game is drawn when one of the following endings arises:
      (a)  king against king;
      (b)  king against king with only bishop or knight;
      (c)  king and bishop against king and bishop, with both bishops
           on diagonals of the same color.
      This immediately ends the game.

11.5  The game is drawn upon agreement between the two players. This
      immediately ends the game.

11.6  The game is drawn when the same pattern of pieces appears for the
      third time for a given player. The pattern is considered the same if
      pieces of the same kind and color occupy the same squares, and if all
      the possible moves of all the pieces are the same.


TABLE OF CONTENTS


FIGURE 1

_ _ _ _ _ _ _ _ _ _ _ _ | | | | | | 10 > | |* * *| | |* * *| |_ _ _|_ _ _|_ _ _ _ _ _|_ _ _|_ _ _| | | | | | | | 9 > |* * *| X |* * *| |* X *| | |_ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _| | | | | | 8 > |* * *| |* * *| | |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | 7 > | X |* X *| X |* X *| <-- |_ _ _|_ _ _|_ _ _|_ _ _| | Black's Board overlaps the | | | | | | Neutral Board on these ranks 6 > |* X *| X |* X *| X | <-- |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | 5 > | X |* X *| X |* X *| <-- |_ _ _|_ _ _|_ _ _|_ _ _| | The Neutral Board overlaps | | | | | | White's Board on these ranks 4 > |* X *| X |* X *| X | <-- |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | 3 > | |* * *| |* * *| _ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _ | | | | | | | 2 > | |* X *| |* * *| X |* * *| |_ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | 1 > |* * *| | |* * *| | |_ _ _|_ _ _| |_ _ _|_ _ _| ^ ^ ^ ^ ^ ^ a b c d e f

Asterisks (*) indicate dark squares. X's indicate overlapping squares.

FIGURE 1

Return to Section 2.2


FIGURE 2

FRONT VIEW SIDE VIEW 11 12 |___________| black |___________| | | board | | 9 10 6 8 |___________| neutral |___________| | | board | | 5 7 2 4 |___________| white |___________| | | board | | 1 3 ^ ^ QUEEN KING PINS PINS

FIGURE 2

Make your choice: Return to Section 2.3 OR Return to Section 7


FIGURE 3

_ _ _ _ _ _ _ _ _ _ _ _ | | | | | | | r |* p *| | p |* r *| |_ _ _|_ _ _|_ _ _ _ _ _|_ _ _|_ _ _| | | | | | | | |* n *| p/b |* q *| k |*p/b*| n | |_ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _| | | | | | |* p *| p |* p *| p | |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | |* * *| |* * *| |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | |* * *| |* * *| | |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | |* * *| |* * *| |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | |* * *| |* * *| | |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | P |* P *| P |* P *| _ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _ | | | | | | | | N |*B/P*| Q |* K *| B/P |* N *| |_ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | |* R *| P | |* P *| R | |_ _ _|_ _ _| |_ _ _|_ _ _|

LEGEND

Asterisks (*) indicate dark squares.

K - white king k - black king Q - white queen q - black queen R - white rook r - black rook N - white knight n - black knight B - white bishop b - black bishop P - white pawn p - black pawn B/P- white bishop over p/b- black pawn over white pawn black bishop

FIGURE 3

Return to Section 3.2


FIGURE 4

_ _ _ _ _ _ _ _ _ _ _ _ | | | | | | | a10 |*b10*| | e10 |*f10*| |_ _ _|_ _ _|_ _ _ _ _ _|_ _ _|_ _ _| | | X | | | X | | |* a9*| b9 |* c9*| d9 |* e9*| f9 | |_ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _| | | | | | |* b8*| c8 |* d8*| e8 | |_ _ _|_ _ _|_ _ _|_ _ _| | X | X | X | X | | b7 |* c7*| d7 |* e7*| <-- |_ _ _|_ _ _|_ _ _|_ _ _| | Black's Board overlaps the | X | X | X | X | | Neutral Board on these ranks |* b6*| c6 |* d6*| e6 | <-- |_ _ _|_ _ _|_ _ _|_ _ _| | X | X | X | X | | b5 |* c5*| d5 |* e5*| <-- |_ _ _|_ _ _|_ _ _|_ _ _| | The Neutral Board overlaps | X | X | X | X | | White's Board on these ranks |* b4*| c4 |* d4*| e4 | <-- |_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | b3 |* c3*| d3 |* e3*| _ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _ | | X | | | X | | | a2 |* b2*| c2 |* d2*| e2 |* f2*| |_ _ _|_ _ _|_ _ _|_ _ _|_ _ _|_ _ _| | | | | | | |* a1*| b1 | |* e1*| f1 | |_ _ _|_ _ _| |_ _ _|_ _ _|

Asterisks (*) indicate dark squares. X's indicate overlapping squares.

FIGURE 4

Return to Section 6


About the Chessboard

The design of the chessboard pictured above is based on information given in the Starfleet Technical Reference Manual, though it was modified slightly as indicated below:

The chessboard is 26.625" high overall. The fixed boards are 9.625" square with an 8" spacing between the top surfaces of adjacent fixed boards.

The bottom-most portion of the stand was made from the base of a microphone stand. The remainder of the base is aluminum, and the circular frame is 0.5" steel bar stock. The boards and corner pins are made of Acrylite, and the attack board posts are plexiglass tubing.

TABLE OF CONTENTS


Origin of the Rules

After the completion of my own chessboard, I began the search for rules of play. I found them in great abundance, but each seemed flawed in some way. A common example involves the starting position of the movable attack boards, where White's pieces are positioned on a level between fixed boards, while Black's are not.