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Subject: Re: EPD

Author: Manfred Rosenboom

Date: 03:49:41 11/25/99

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On November 24, 1999 at 22:02:22, Nicolas Carrasco wrote:

>Hi,
>
>While I finished my EPD(basic input) rutines I guessed to know if there are any
>parameter to set the FIFTY move draw variable and the CASTLE status. I think
>that 3 fold repetition data can't be save because it will be unconfortable to
>humans.
>
>Can anyone answer that to me?

Please download the PGN standard from

ftp://chess.onenet.net/pub/chess/PGN/Standard

or have a look at the online verion at

http://www.geocities.com/CapeCanaveral/Launchpad/2640/pgn/pgn_spec/pgn_spec.htm

You will find all your questions answered in the PGN standard:

16.2.3.3: Castling availability
The third field represents castling availability. This indicates potential
future castling that may or 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 present. If White has kingside castling availability, the
uppercase letter "K" appears. If White has queenside castling availability, the
uppercase letter "Q" appears. If Black has kingside castling availability, the
lowercase letter "k" appears. 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.


16.2.5.14: Opcode "hmvc": halfmove clock
The opcode "hmvc" represents the halfmove clock associated with the position.
The halfmove clock of a position is equal to the number of plies since the last
pawn move or capture. This information is used to implement the fifty move draw
rule. It always takes a single operand that is the non-negative integer value of
the halfmove clock.

This opcode is used to explicitly represent the halfmove clock in EPD that is
present by default in FEN as the fifth field. Halfmove clock information is
usually omitted from EPD because it does not affect move generation (commonly
needed for EPD-using tasks) but it does affect game termination issues (commonly
needed for FEN-using tasks). Because of the desire for space optimization for
large EPD files, halfmove clock values were dropped from EPD's parent FEN. The
fullmove number information was similarly dropped.


16.2.5.20: Opcode "rc": repetition count
The "rc" opcode is used to indicate the number of occurrences of the indicated
position. It takes a single, positive integer operand. Any position, including
the initial starting position, is considered to have an "rc" value of at least
one. A value of three indicates a candidate for a draw claim by the position
repetition rule.




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