Wednesday, 26 August 2009

Second Life chess board with rules

Found this chess game in Second Life, with the rules included below:

The Second Life ProChess board V.1.00

The ProChess board is the most advanced chess board available in
Second Life for serious chess enthusiasts, with full support for take
backs and setting up special positions or problems, all for a
relatively low prim count.

For casual play, there is an outstanding table built by XYlor
Baykslef, that you can get for free at the SL Chess Club. Be warned
though, it rezzes a whopping 278 prims at playing time. It's the same
table you may have already found at the welcome area.

How to play

-- Starting a game:

To play a game, you and your opponent simply have to be in view of the
board. Touch (left-click) the White King symbol UNDER the chess board,
a dialog will pop up asking you which color you want to play. Choose
one, and let your opponent pick the other one the same way. Your name
and your opponent's should appear as hovering text above the board.

Next, touch the "RESET" word under the board, to set pieces back to
the starting position (or you can start playing the position

-- Playing a move:

Playing is now just a matter of touching first the piece you want to
move and then the destination square. The touched piece will move if
the move is legal: The board validates moves and assigns turns.

-- Castling:

For castling, touch the square of the king and then the destination

-- En Passant:

To take a pawn "en passant", touch the pawn that will take the other,
and then the destination square, just like a normal move. The board
will take care of removing the taken pawn, if it is legal of course.

-- Take back:

To take a move back, just touch the "TAKE BACK" word under the board.
Your opponent will see a request pop up, and he can either accept or
decline the takeback. If he accepts, the game will reset itself to the
last position where you had to play. If you're playing both sides,
takeback will just move back one ply at a time.

Command line (board owner only)

The owner of the ProChess board can pass commands at any time on
channel 99 (or another configured channel) or by prefixing them with
"@@" on channel 0 (general chat). For example, the owner can RESET the
board at any time just by typing:


Commands and command parameters are case insensitive, except for piece
symbols: white pieces are uppercase, black pieces are lowercase.

Available commands

-- Channel

Sets a channel for board commands. Useful especially if several boards
are in the same location, in tournament situations.

Note that even if you forget the channel you've set previously, the
"@@" syntax on channel 0 (chat channel) is always available to switch
it back to one you know or to invoke the "info" command.

-- FEN:

Sets a position described in FEN notation on the board. For example
this is exactly equivalent to the "RESET" command:

FEN rnbqkbnr/pppppppp/////PPPPPPPP/RNBQKBNR w QKqk -

The following puts queens of alternating colors on the A1-H8 diagonal,
with no care for castling, side to play or en passant, as it is of
course an illegal position:

FEN 7Q/6q/5Q/4q/3Q/2q/1Q/q

-- M :

Moves a piece. Upper and lower case are supported, as is any delimiter
between the squares: "m e2 e4", "M e2-e4", "M e2/e4" are all valid
move commands. The board will NOT play an invalid move.

-- P :

Sets a piece on a square. Uppercase letters designate white pieces,
lowercase letters designate black pieces. An empty square is just a
dash "-". In detail:

P/p : pawn
K/k : king
Q/q: queen
R/r: rook
N/n: knight
B/b: bishop
-: empty square

For example: "P Re4" sets a white rook on square e4, regardless of
what piece may or may not have been there before.

The board does NOT check that the resulting position is legal.

-- Reset

Resets the board to the starting position.

-- Clear

Empties the board.

-- Info

Lists all current board info to channel 0 (main chat).

-- Side

Sets the side to play. "w" for White, "b" for Black.

For example: "side w" to set White to play.

-- Castling

Sets castling rights for the position, in FEN notation (FEN is
described below).

For example: "castling KQ" to disallow Black castling yet allow both
king and queen castling for White.

-- Lock

When lock is on players can not take side anymore. Only the board
owner can unlock the board by saying "lock off".

-- Pop

Pop moves back the game one ply (one move by one player) and that move
is lost, i.e. you cannot move forward again to undo the "pop" command.

-- Back

Back moves the game one ply.

-- Forward

Forwards moves the game forward one ply.

The FEN Notation

The Forsyth-Edwards Notation - Standard is a part of the Portable Game
Notation (PGN) - Standard.

FEN is "Forsyth-Edwards Notation"; it is a standard for describing
chess positions using text.

A single FEN record uses one text line of variable length composed of
six data fields.

1.1 - History

FEN is based on a 19th-century standard for position recording
designed by the Scotsman David Forsyth, a newspaper journalist. The
original Forsyth standard has been slightly extended for use with
chess software by Steven Edwards with assistance from commentators on
the Internet. This new standard, FEN, was first implemented in
Edwards' SAN Kit.

1.2 - Uses For A Position Notation

Having a standard position notation is particularly important for
chess programmers as it allows them to share position databases. For
example, there exist standard position notation databases with many of
the classical benchmark tests for chessplaying programs, and by using
a common position notation format many hours of tedious data entry can
be saved. Additionally, a position notation can be useful for page
layout programs and for confirming position status for e-mail

1.3 - Data Fields

FEN specifies the piece placement, the active color, the castling
availability, the en passant target square, the halfmove clock, and
the fullmove number. These can all fit on a single text line in an
easily read format. The length of a FEN position description varies
somewhat according to the position.

A FEN description has six fields. Each field is composed only of
non-blank printing ASCII characters. Adjacent fields are separated by
a single ASCII space character.

1.3.1 - Piece Placement Data

The first field represents the placement of the pieces on the board.
The board contents are specified starting with the eighth rank and
ending with the first rank. For each rank, the squares are specified
from file a to file h. White pieces are identified by uppercase SAN
piece letters ("PNBRQK") and black pieces are identified by lowercase
SAN piece letters ("pnbrqk"). Empty squares are represented by the
digits one through eight; the digit used represents the count of
contiguous empty squares along a rank. A "/" is used to separate data
of adjacent ranks.

1.3.2 - Active Color

The second field represents the active color. A lower case "w" is
used if White is to move; a lower case "b" is used if Black is the
active player.

1.3.3 - Castling Availability

The third field represents castling availability. This indicates
potential future castling that may of may not be possible at the
moment due to blocking pieces or enemy attacks. If there is no
castling availability for either side, the single character symbol "-"
is used. Otherwise, a combination of from one to four characters are

If White has kingside castling availability, the uppercase letter "K"

If White has queenside castling availability, the uppercase letter "Q"

If Black has kingside castling availability, the lowercase letter "k"

If Black has queenside castling availability, then the lowercase
letter "q" appears.

Those letters which appear will be ordered first uppercase before
lowercase and second kingside before queenside. There is no white
space between the letters.

1.3.4 - En Passant Target Square

The fourth field is the en passant target square. If there is no en
passant target square then the single character symbol "-" appears.
If there is an en passant target square then is represented by a
lowercase file character immediately followed by a rank digit.
Obviously, the rank digit will be "3" following a white pawn double
advance (Black is the active color) or else be the digit "6" after a
black pawn double advance (White being the active color).

An en passant target square is given if and only if the last move was
a pawn advance of two squares. Therefore, an en passant target square
field may have a square name even if there is no pawn of the opposing
side that may immediately execute the en passant capture.

1.3.5 - Halfmove Clock

The fifth field is a nonnegative integer representing the halfmove
clock. This number is the count of halfmoves (or ply) since the last
pawn advance or capturing move. This value is used for the fifty move
draw rule.

1.3.6 - Fullmove Number

The sixth and last field is a positive integer that gives the fullmove
number. This will have the value "1" for the first move of a game for
both White and Black. It is incremented by one immediately after each
move by Black.

1.4 - Examples

Here's the FEN for the starting position:
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

And after the move 1. e4:
rnbqkbnr/pppppppp///4P3//PPPP1PPP/RNBQKBNR b KQkq e3 0 1

And then after 1. ... c5:
rnbqkbnr/pp1ppppp//2p5/4P3//PPPP1PPP/RNBQKBNR w KQkq c6 0 2

And then after 2. Nf3:
rnbqkbnr/pp1ppppp//2p5/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2

For two kings on their home squares and a white pawn on e2 (White to
move) with thirty eight full moves played with five halfmoves since
the last pawn move or capture:
4k3//////4P3/4K3 w - - 5 39

Rober1236 Jua the Cyber Trekker of Second Life
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