Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Full definition for FEN

Author: Dave Gomboc

Date: 10:54:53 06/05/99

Go up one level in this thread


On June 05, 1999 at 13:22:31, José de Jesús García Ruvalcaba wrote:

>On June 04, 1999 at 20:20:38, Dave Gomboc wrote:
>
>>On June 04, 1999 at 19:39:36, Mike Leahy wrote:
>>
>>>On May 27, 1999 at 20:48:55, Dann Corbit wrote:
>>>
>>>>From the PGN Standard
>>>
>>>
>>>>16.1.4: 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/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
>>>
>>>This is problematic.  The position is identical to...
>>>
>>> rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1
>>
>>The position you describe with the string not containing "e3" is not technically
>>reachable (even ignoring the ply count for now) because Black can't lose a move
>>while White slides a pawn first to e3, then to e4.
>>
>
>	If we ignore the ply counts, then the position is reachable: 1. e3 Nc6 2. Bd3
>Nb8 3. Be2 Nc6 4. Bf1 Nb8 5. e4
>	Of course, the last digit for the fen string would now be 5 instead of 1, since
>it follows black's fifth move.

Good point.  I forgot that the bishop was free to slide after e3.

Dave



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.