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MatPlus.Net Forum General Codex question
 
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(1) Posted by Joost de Heer [Friday, Feb 5, 2021 11:59]

Codex question


 QUOTE 

Article 18 – Repetition of Position

A position is considered as a draw if it can be proved that an identical position [21] has occured three times in the proof game combined with the solution.

[21] Identical position means the same kinds of pieces on the same squares with the same move rights.


IMO this is missing 'and the same side to move' in the footnote. And should 'and will forcibly occur in the future of the proofgame' also be included?
 
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(2) Posted by Torsten Linß [Friday, Feb 5, 2021 12:53]

I think this is [intended to be] included in "move rights". If it's black to move, then white pieces have no right to move, and vice versa.

Hmm, unless there are only neutral pieces on the board...
 
 
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(3) Posted by Andrew Buchanan [Friday, Feb 5, 2021 15:23]

I’ve always interpreted this is a being just a reminder of the real rule in the Laws. There are semantic issues there. If move rights don’t exist when one doesn’t have the move then how does that impact checks & castling. There are no terrible paradoxes but it’s something one only wants to go through once and it should be in the Laws
 
   
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(4) Posted by Neal Turner [Friday, Feb 5, 2021 19:24]

Do these type of rules have anything to do with problem chess?
We have the rules of the game - which are pertinent to chess problems - and then there's Tournament Rules, which are about regulating the play under tournament conditions.

With the Repetition rule the draw isn't automatic - one of the players has to actually claim the draw by calling over the arbiter.
Did you see Peter Leko, commentating at Wijk, telling how sometimes players would keep repeating as it was considered to be losing face to be the one to call the arbiter!

With a chess problem there is no arbiter, so how can one claim a draw?
 
   
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(5) Posted by Nikola Predrag [Friday, Feb 5, 2021 20:14]

Well, in problems, some abstract perfect arbiter is supposed to be watching. Otherwise, how would we deal with illegalities?
But the question is - what might be a natural purpose of repeating a position in problems and claiming a draw, as a part of a solution?
 
 
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(6) Posted by Joost de Heer [Saturday, Feb 6, 2021 09:05]

 QUOTE 

Do these type of rules have anything to do with problem chess?

Retractors use the repetition rule quite extensively.
 
   
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(7) Posted by Nikola Predrag [Saturday, Feb 6, 2021 13:27]

Repetition in chess is not the same as it is in problems (where no player's claim is needed for ending the game). The purpose of the rule is essentially different.
So, why a 3-times occurrence? For trivial repetition of the same moves, one repetition should be enough.
For possibly 'interesting' (longer and different) ways, more repetitions should be allowed.
(Has the swapping of 2 or more pieces of the same type been done?)
 
   
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(8) Posted by Andrew Buchanan [Saturday, Feb 6, 2021 14:41]

 QUOTE 
With a chess problem there is no arbiter, so how can one claim a draw?

And chess problems have no players, no clocks and no score pads, all parts of the over the board ritual of claiming draw by repetition. Instead the codex replaces all this complexity with a convention that the game definitively ends if the position occurs for a third time.

This is the default way that a game will finish in draw if there is no stalemate. Arguably we need it so that some end game study outcomes are well defined. So there is no truncation of interesting play (such as can happen with 50 move and dead position) so that there is no interest to restrict the draw by repetition application to just retro problems (although both 50M & DP can also make some forward problems sound which would otherwise not be so.

Three is the magic number in life generally. Here it allows for both retro and forward play to be combined in a problem. Five doesn’t get us anything more.

The definition of position itself can be taken from the rules which I think in the last few years have become clear, and discussed extensively elsewhere.

@Nikola: someone must have a shot at transposing identical units but I can’t think of any offhand. Go for it! :-)
 
   
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(9) Posted by Hauke Reddmann [Saturday, Feb 6, 2021 16:37]

@Andrew:
You mean like...(wants to castle)(realizes that Rh1 has run around)
(flash of genius)(Ra1 never moved yet)(J'ADOUBE!!)(swaps Ra1 and Rh1)
(castles)(gets nuked by arbiter)
 
 
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(10) Posted by Nikola Predrag [Saturday, Feb 6, 2021 16:39]

Andrew, are you serious about the 'magic' reasons?
In OTB games, it's a part of the battle - in an unclear position, both players repeat once, to test whether the opponent is willing to take a risk for the win, before one's own decision.
As long as the stipulation clearly determines the goals of each side, such a testing is pointless and thus superfluous.
 
   
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(11) Posted by Andrew Buchanan [Sunday, Feb 7, 2021 08:00]

@Nikola: am I ever serious? :-) See https://en.wikipedia.org/wiki/Rule_of_three_(writing)

 QUOTE 
The rule of three is a writing principle that suggests that a trio of events or characters is more humorous, satisfying, or effective than other numbers.

We are a tribe of trickster storytellers, so this principle can be relevant. But other numbers also pop up. For helpmates, 2 is generally sufficient, as it allows a theme to be visited in a binocular way. 3 is the gateway to cycles. Alexandr Kisljak felt the number 4 was the most significant (4 corners, 4 orientations of the board, 4 promotion targets for allumwandlung, board size=4x4x4, etc). But here in Asia, 4 is very unlucky. 5 is Excelsior, 6 is the number of different units, etc.

For over the board chess, if a single repetition was enough for someone claim a draw, it would be too easy to stumble into, or to make a move which does not allow to be undone. It would be a kind of orthodox Haaner Schach! So less chaotic, more deliberate, to insist that a position occurs three times before draw is claimed.

And for so-called "retroactive" compositions with both retro & forward play, 3 is perfect as it allows past, present & future occurrences.

Let me finish by sharing the lyrics of one of the best old English folk songs. It builds, like "The twelve days of Christmas", but with a much better tune, and the final verse goes:
 QUOTE 

I'll sing you twelve, O
Green grow the rushes, O
What are your twelve, O?
Twelve for the twelve Apostles
Eleven for the eleven who went to heaven,
Ten for the ten commandments,
Nine for the nine bright shiners,
Eight for the April Rainers.
Seven for the seven stars in the sky,
Six for the six proud walkers,
Five for the symbols at your door,
Four for the Gospel makers,
Three, three, the rivals,
Two, two, the lily-white boys,
Clothed all in green, O
One is one and all alone
And evermore shall be so.

 
   
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(12) Posted by Nikola Predrag [Sunday, Feb 7, 2021 13:48]

Are you serious? Are you serious? Are you serious?
Are Are Are you you you serious serious serious ???
AAArrreee yyyooouuu ssseeerrriiiooouuusss???
:-) :-) :-)
 
   
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(13) Posted by Nikola Predrag [Sunday, Feb 7, 2021 13:55]

I'm not sure which way of repeating the same thing you think would be best in our 'tribe of trickster storytellers'.
 
   
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(14) Posted by Andrew Buchanan [Sunday, Feb 7, 2021 14:15]

Well now, since you ask... :-)
"Am I ever X?" is an ambiguous rhetorical question.
It could mean "I am never X" or in American usage it could mean: "I am totally X".
and that's probably as far down this rabbit hole as I should go: I will let you have any last word should you choose.
 
   
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(15) Posted by Nikola Predrag [Sunday, Feb 7, 2021 18:16]

I just don't understand the meaning and relevance of your post (11) and I suspect you don't understand it yourself. I won't even try to understand your last post (14).
 
   
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(16) Posted by Alain Villeneuve [Sunday, Feb 7, 2021 23:25]

Sretno, Nikola !!!
 
   
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(17) Posted by Nikola Predrag [Monday, Feb 8, 2021 00:23]

Hvala Alain, puno sreće i dobro zdravlje! Hopefully, we'll meat again reasonably soon.
 
 
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MatPlus.Net Forum General Codex question