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Subject: Re: Is This A Repetition?

Author: Mike S.

Date: 14:36:11 06/06/03

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On June 06, 2003 at 15:48:33, William H Rogers wrote:

>Not according to my understanding of the rules of chess. The repetition must be
>complete duplication of the last three moves. In other words the player must
>make the same moves three times in a row, not seperated by a few others in the
>mean time.

No, the rule is repetition of the *position* (not the moves), with the same side
having the move and the same move rights. Also, it's not necessary that the
repetition happens directly within 4 moves, IOW. 8 plies. It can be "somewhere
earlier" in the game too, that's sufficient.

(It's not possible to repeat a position *twice* with three moves... :-))

The original FIDE wording is:

"5.2  (...)

The game may be drawn if any identical position is about to appear or has
appeared on the chessboard at least three times. (See Article 9.2)

9.2  The game is drawn, upon a correct claim by the player having the move, when
the same position, for at least the third time (not necessarily by sequential
repetition of moves)

is about to appear, if he first writes his move on his scoresheet and declares
to the arbiter his intention to make this move, or

has just appeared, and the player claiming the draw has the move.

Positions as in (a) and (b) are considered the same, if the same player has the
move, pieces of the same kind and colour occupy the same squares, and the
possible moves of all the pieces of both players are the same.
Positions are not the same if a pawn that could have been captured en passant
can no longer be captured or if the right to castle has been changed temporarily
or permanently."

The last paragraph points to an interesting possibility:

Zepler, Die Schwalbe 1929
[D]r3k3/2Qp3R/1p6/1b2K3/4p3/8/5p2/8 w q - 0 1
# in 4 (! not longer)

Some engines will never find it (some do). - But I think, this is a special
detail engines can afford to miss... although, it *may* lead to wrong draw
claims.

Btw. in the "60 memorable", Fischer points to that detail of the rule once (I
can't remember in which game at the moment).

But of course, engines should always recognise the more "normal" cases, when the
position(s) occured many moves ago, too.

Regards,
M.Scheidl



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