[Retros] 50-moves rule and mate

pastmaker at aol.com pastmaker at aol.com
Tue Jan 16 12:17:42 EST 2007



This aging lawyer disagrees with my esteemed colleague's legal conclusion.

I have no problem with a reading of this statute that entails that every "move" is tentative -- after all, it might have been patently illegal (a bishop moving horizontally, for example). But surely the other player can not be "on the move" if the determination of the legality is in process. Similarly, if a determination of the effect of a move is required (e.g. is it correct, as asserted by the player who has just moved and claimed a draw by repetition, that he has just made a move that recreates a position he has existed twice before after his move?), it cannot be the case that the other player is "on the move" before that determination is complete.

I'm OK with limbo while the validity or effect of a move is under determination, but not with the move shifting to the other player (along with those rights that belong to a player "on the move") during that limbo. How can the move shift if we are still finding out what happened? During the determination process, both must be in limbo.

Once it is determined that the move is valid, then (and only then) does the "on the move" status shift, unless, of course, the game ended by virtue of something that resulted from that now determined-to-be-valid move, such as that it gave checkmate.

I stand by my earlier reasons.


Tom


-----Original Message-----
From: andrew at anselan.com
To: retros at janko.at; pastmaker at aol.com
Sent: Tue, 16 Jan 2007 10:59 AM
Subject: RE: [Retros] 50-moves rule and mate


Hi Tom,

Thanks for your interesting mail. You wrote:


>under the FIDE rules for over-the-board play only the player on the move

>can claim a draw. The checkmating move is unassailable under that regime

>because the other player (i) is not on the move when the checkmating move

>is played, and so must remain mute while the move is played, and (ii) never

>regains the move, as the play of the checkmating move ends the game.


I agree with your conclusion that # trumps 50M (if it's the mated player who
wants to claim), but I disagree with how you reach that conclusion.

In order to know that it is #, you have to examine the new position,
according to Art 1.2 ("The objective of each player is to place the
opponent's king 'under attack' in such a way that the opponent has no legal
move which would avoid the 'capture' of the king on the following move.")

In this position, the possibly checkmated player already has the move.
Firstly, because Art 1.1 says he does ("A player is said to 'have the move',
when his opponent's move has been made.") Secondly, because in the new
position you can't verify the legal moves correctly unless the right player
has been assigned the move. Thirdly, note the use of the present tense in
Art 1.2.

Surely Guert Gijssen at Chess Café must have answered this question before?
It's not really something we problemists should have to guess.

Notes:

(1) My reading is that stalemate and dead position are checked for at the
same time as checkmate... just after the player has acquired the move, but
before the new player can do anything.

(2) I think Draw by Repetition is handled in the same way as 50M, and if it
mattered (which I don't think it ever can in the game of chess because the
situations are mutually exclusive) would be trumped by mate/pat/death.

(3) But we've really only handled half of it. We were assuming that it was
the mated player who wanted to claim the draw. In the weird world of
composition, it could easily be the mating player who wants to claim the
draw, in which case if we look at the Laws of the Game again, it is 50M
which trumps #.

(4) Now how does that affect chess compositions? The Codex doesn't give me
adequate support to answer that question.

The key point is that in the game, depending on who does the claiming, 50M
or # may prevail. For this reason, it will not be so easy for Guus to craft
a similar convention for 50M which worked to some extent for Rep.

Regards,
Andrew.
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