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Help For Chex

(Copyright (c) 1994 David Smith)


Welcome to the network Chex server. The rules of Chex are below. The Chex "move" and "draw" commands are explained here. Other commands are the same for all pbmserv games.

chex move board userid password move[#moveno]
Make a move. A move is one of the following forms:


<piece> names the piece moved
<capture> indicates that the move is a capture
<to> names the destination square

These will be explained in more detail in a moment. But there are a few things to clarify first. The chex board consists of ranks (horizontal rows) and files (vertical columns). Ranks are described by a number, 1+, while files are described by a single letter, a+. Pieces are described byb a single letter, K for king, Q for queen, R for rook, B for bishop, N for knight, and P for pawn.

Most moves are described simply as a piece (one character) and where to move it to (two more characters). For example, Nf3 moves a knight to f3. If more than one knight can move to f3 (such as from d2 or g1), you'll need to distinguish between them by including the knight's rank or file, such as Ngf3 or N1f3.

In some cases the notation is ambiguous. For example, Bc4 could mean 'move a bishop to c4' or 'move a pawn from file b to c4'. The server will try to interpret the move both ways. If there is only one correct interpretation, that move will be made. Otherwise, the move will be rejected. In this case the player can resort to the <from>-<to> format.

Now for the details:

(1) If the piece moved is not a pawn, it must be named (with the letter K, Q, R, B, or N). If more than one such piece could move to the destination square, the original rank or file must be specified. On rare occasions both rank and file may be necessary. For example, if rooks at A1 and H1 could both move to D1, use RA to specify the rook at A1.
(2) If the piece moved is a pawn, it is not named. If it is capturing, the original file must be specified.
An 'x' indicates that the move is a capture. This is *not* required-- if omitted, the server will figure out it's a capture. However, if an 'x' is included, the server will reject the move if it is not a capture.
This is of the form <file><rank>.
chex draw board userid password
chex move board userid password draw
Draw a tile from your stack. Once drawn and revealed, you will then place the tile with a move indicating the position when you would like it placed.

Rules of Chex

Here are the basic rules for Chex (Copyright (c) 1994 David Smith) a variant of Chess

Object of the Game

To capture your opponent's king.

Unlike standard Chess, Chex is played on a dynamic board which grows and shrinks to enclosed the pieces currently in play. The board is not limited to 8x8. It may grow to any width and/or height.

The players' pieces do not start on the board. Rather they are off the board, and "drawn" randomly to be added to play.

Movement Rules

White moves first. On your initial turn, you draw a piece and put it into play at position, A1. A border row of 1 tile is then added to the board, so the piece will appear to be at B2. Black then draws a piece and puts it into play at some position adjacent to the white piece.

Thereafter, a turn consists of either:

  1. Drawing a piece and adding it to the board
  2. Making a "normal" chess move (see chess help page) subject to the following restriction:

    When the movement or capture is complete, any remaining pieces must remain connected (directly or indirectly) to all other pieces. In other words, you may not "break the board".


           a   b   c   d   e
        +---+---+---+---+---+     Black
      4 |:::|   |:::|   |:::|  4
      3 |   |:N:| B |:::|   |  3
      2 |:::|*P*|:::|*P*|:::|  2
      1 |   |:::|   |:::|   |  1
        +---+---+---+---+---+     White
          a   b   c   d   e

In this example, white's bishop can not move. He is currently, "tagged" by the black pawns. If he moves, he would leave a "break" in the board. White's kNight is free to move to D4,D2,C1 or A1. Similarly, black's pawns are also unable to move. If it were black's turn, he would be forced to draw a piece.

When a player has drawn and placed in play all 16 own pieces, the game continues with that player being reduced to moving his or her pieces only until a result is achieved.

White pawns move "north". Black pawns move "south".

There is no pawn promotion, en passant capture or castling in this variant of chess.

Victory Conditions

The game is over when one player's king has been captured. There is currently no check/checkmate detection in this chess variant due to the complexity of the "breaking the board" condition.

The game is a stalemate if a player draws their King and is unable to put it into play "safely" (such that the next player would immediately capture it. Again, this is not currently detected by the game engine. If you draw your King, and can not put it into play, simple propose a "draw". Your opponent is honor bound to accept it.

The game is also a stalemate if you have no pieces remaining to draw, and are unable to make a legal move (that is, without "breaking the board"). Again, if this happens, propose a draw for your opponent to accept.


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