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Subject: Re: 3fold repetition, ep squares and EGTBs

Author: Rafael Andrist

Date: 02:09:13 08/05/01

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On August 04, 2001 at 13:03:50, Bruce Moreland wrote:

>On August 03, 2001 at 16:57:06, Miguel A. Ballicora wrote:
>
>>On August 03, 2001 at 15:44:09, Dieter Buerssner wrote:
>>
>>>A small question about chess rules. Assume the following position (which does
>>>not make any other sense, than to show my point):
>>>
>>>[D] 3kr3/8/8/8/3p4/8/4P3/3RK3 w - - 0 1
>>>
>>>1. e4
>>>
>>>Now black cannot capture ep. Then just some stupid moves:
>>>
>>>1...Kd7 2. Ke2 Kd8 3. Ke1
>>>
>>>Again the same postion as after 1. e4.
>>>
>>>3...Kd7 4. Ke2 Kd8
>>>
>>>Can at this point White claim a draw, by saying "I intend to move Ke1 - 3fold
>>>repetion"?
>>>
>>>I assume yes. If this is correct: Are you handling this correctly in your
>>>chess-engine?
>>
>>Yes, it can be claimed draw because the 3 positions are identical. In neither of
>>those dxe3 is possible. I do not remember the exact wording but the spirit of
>>the rules were that the 3 positions should be "photographically" and
>>"dynamically" identical.
>
>The other interesting case is castling.
>
>Let's say we are in a position where castling is "possible" for white, but not
>legal now.  The reason it isn't legal is that white is in check, and is forced
>(in this case) to move his king.
>
>If this position appears again, the same exact moves are legal in both cases,
>but when I asked this question in rec.games.chess.misc, people seemed to think
>that this was a different position.
>
>The castling flags differentiate the position up until the piece is actually
>moved.  The position is checked for sameness right before the piece moves.
>
>I wonder if anyone at FIDE has thought this through?
>
>bruce
>

According to the FIDE rules, the positions are different.

Rafael B. Andrist



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