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MatPlus.Net  Forum General Alsatian Circe: is there a definitive definition? |
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| | | (1) Posted by Eugene Rosner [Thursday, Aug 29, 2013 03:51] | Alsatian Circe: is there a definitive definition?
Hi again everyone! I'm currently in the middle of a new Alsatian but I'm unsure of the exact definition of AC. can anyone provide the absolute definition?
| | | (2) Posted by Kevin Begley [Thursday, Aug 29, 2013 06:30]; edited by Kevin Begley [13-08-29] |
"Alsatian Circe is a Circe where a capture is not allowed if the resulting position is illegal under the rules of orthodox chess."
Source: http://www.janko.at/Retros/Glossary/Circe.htm
Is there some specific ambiguity?
Example:
Jean Zeller
Feenschach, 1980
 (= 4+1 )
h#2 Circe + Alsatian
1.Kb7 Ba1 2.Ka8 b7# (3.Kxb7 [+wPb2] ?? is illegal).
ps: if you really want to take advantage of this rule definition (which is based upon an undefined orthodoxy), you might consider applying dead reckoning analysis (to rule certain minimalist positions as illegal).
Edit: surprisingly, this very simple definition seems quite resilient -- I don't see how Dead Reckoning puts a dent in it.
| | | (3) Posted by Eugene Rosner [Thursday, Aug 29, 2013 13:48] |
can the diagram position be illegal in orthodox chess, rendering basic captures and rebirths illegal?
while during the play, certain captures can become legal....
| | | (4) Posted by Thomas Brand [Thursday, Aug 29, 2013 20:11] |
@ Eugene:
No, the diagram must be a legal position according to the orthodox chess rules. This is explicitely stated in the defining article (Jean Zeller: Elsässisches Circe; feenschach 49, 1980, pp.298-303).
@Kevin:
I don't see why the 'orthodoxy' might be undefined? A position is 'orthodoxly legal' if and only if there exists a proof game according the orthodox rules of chess leading to this position.
So in the Zeller example (taken from the feenschach article mentioned above) the move 3.Kxb7[Pb2] is illegal, since the resulting position were 'orthodoxly illegal', i.e. there is no orthodox proof game resulting in this position, notably with wBa1 & wPb2.
| | | (5) Posted by Kevin Begley [Thursday, Aug 29, 2013 20:46]; edited by Kevin Begley [13-08-29] |
@Thomas,
>I don't see why the 'orthodoxy' might be undefined?
>A position is 'orthodoxly legal' if and only if there exists a proof game according the orthodox rules of chess leading to this position.
In theory, orthodox is well defined; but, in practice, not everybody agrees on it -- particularly given dead reckoning, which prematurely ended some old orthodox studies, before their intended stalemates; and, it likely has impacted a number of stalemate problems (without anybody noticing -- particularly in s=n, where the orthodox game typically ends, now (under the new DR rules), prior to the achievement of a stalemate.
Orthodox chess rules are not fixed; and, defining fairy conditions according to the FIDE Players Rulebook has proven to be a flawed enterprise.
This is an issue nobody likes to admit, because it's more comforting to pretend that orthodox chess has been consistent, since before Paul Morphy went to the Opera.
>So in the Zeller example (taken from the feenschach article mentioned above) the move 3.Kxb7[Pb2] is illegal, since the resulting position were 'orthodoxly illegal',
>i.e. there is no orthodox proof game resulting in this position, notably with wBa1 & wPb2.
Agreed -- and that is certainly an interesting feature of the condition.
And, as I stated, the condition seems fairly resilient (at first I thought that dead reckoning might impact it, but it doesn't immediately seem possible).
The only questionable term I find, in this very elegant definition, is the exact meaning of "position."
Many positions are retro-legal, only if a given player is on the move.
I presume that the term (position) applies not only to piece arrangement, but also to all hidden variables (e.g., player on the move, and castling rights, and en passant rights).
That's the one issue I don't find fully elaborated, in the definition I find for this condition.
Must the position be reachable by some "Shortest Proofgame," or must it be reached by a Proofgame of exact length? (I presume the latter).
| | | (6) Posted by Eugene Rosner [Thursday, Aug 29, 2013 21:46] |
thanks gentlemen. the reference to the original article is key! I'm glad I didn't spend any more time than I had! Oh well, let's see where this idea goes now!
| | | (7) Posted by Kevin Begley [Friday, Aug 30, 2013 03:42] |
Very interesting condition (for anybody who, like me, enjoys both retro and fairy elements)...
And it applies not only to circe (and all forms of circe), but all kinds of fairy conditions (e.g., there's a few Einstein + Alsatian problems).
Good luck with it, Eugene.
| | | (8) Posted by Eugene Rosner [Friday, Aug 30, 2013 03:50] |
thanks Kevin! If I have a chance over the weekend I'll post my idea, although flawed by the improtant alsatian rule that I wasn't sure about!
| | | (9) Posted by Kevin Begley [Friday, Aug 30, 2013 04:35]; edited by Kevin Begley [13-08-30] |
Actually, it took me some thinking, but I think I did find a stress point in the armor of this definition.
Consider:
scheme:
 (= 5+2 )
#1?
Alsatian + Circe Exchange
Is 1.O-O# legal??
Note that there is no legal defense, since all three defenses (...Kxa2[+wPa1]??, ...Kxb2[+wPa1], and ...Kxc2[+wPa1]), would produce an illegal position (no orthodox PG will reach a position with pawns on the first rank) -- despite the fact that all three would be legal under Circe Exchange, where pawns on the first rank cannot move, capture, or give check (don't even get me started on this condition's inconsistency with the default circe form).
So, this would appear to be mate; but, is castling really legal?
According to the rules of Alsatian, the diagram position is retro legal, and the final position (after 1.O-O) is retro-legal.
That is, you can reach both positions by an orthodox proofgame.
Since Alsatian says nothing about the moves (the moves themselves, under the fairy form, in this case circe exchange, can be ortho-illegal) -- Alsatian only pertains to the positions reached after a move -- it would seem to be legal.
However, as I had noted before, it is not exactly clear whether castling rights are part of the "position."
Note that this "position" can NOT be reached, in an orthodox Proofgame, such that it affords white castling rights!
Therefore, it's highly ambiguous (at least to me) whether white can actually castle here -- it all depends upon your definition of "position."
Maybe somebody can ask the inventor to comment.
| | | (10) Posted by Eugene Rosner [Friday, Aug 30, 2013 05:22] |
the orthodox diagram shows that WK must have let in the BK rendering 0-0 illegal. no solution. that's what I think at least!
| | | (11) Posted by Kevin Begley [Friday, Aug 30, 2013 05:35]; edited by Kevin Begley [13-08-30] |
@Eugene,
I was inclined to guess that the move can be ortho-illegal, since the definition of Alsatian pertains only to the resulting diagram (and you can, after all, make ortho-illegal moves, providing the diagram returns to ortho-legality).
However, if this is indeed the case, it begs the question: should the definition use the word "diagram" rather than "position."
I think it's a coin toss, at best, to guess the inventor's intent (I would attempt a consultation, before delving deeply into any of the deliberately murky possibilities).
And, even if castling is legal, I don't think it necessarily answers whether ortho-legality depends upon the player on the move -- though, for the sake of elegance, it would seem preferable to either attribute legality to the diagram, or the full position (including all hidden variables: whose move, castling rights, en passant rights).
The codex already gives an exemption from the hidden variable pertaining to the 50-move rule (so, I don't think that need be explained).
ps: my scheme is poor, because there is no real retro content in any miniature Circe Exchange problem (it begs the question whether castling can be legal under the condition -- I can add a white unit somewhere, to make castling look legal, but it doesn't really provide retro-justification for castling)...
Hopefully, it conveys the idea.
| | | (12) Posted by Thomas Brand [Friday, Aug 30, 2013 16:18] |
@Kevin:
A few remarks:
We can't discuss Zellers intention with him, since he passed away some years ago.
But I think it's clear what his intention was: Your idea is to use the "consequential" interpretation of "legal position", i.e. "forget the history of a position". Jean Zeller did not intend this interpretation, although he did not mention it explicitely. But in his introduction article cited above he tells that it is possible to link both Alsacian an consequential idea, and he shows a problem of this kind, dedicated to Michel Caillaud who had introduced the "consequential" condition -- see pdb P0007666.
So I'm sure Zeller had said "In your scheme 0-0 is illegal!"
He had said this just for a second reason: The scheme is "Circe exchange illegal", since there are less then 32 men on board :-)
Best regards,
Thomas
| | | (13) Posted by Hauke Reddmann [Saturday, Aug 31, 2013 15:31] |
In that case, Zellers interpretation should stand and
Kevins version should be named Alsatian Cousin.
Because you can't have enough Morrissey puns :P
Hauke
| | | (14) Posted by Thomas Brand [Saturday, Aug 31, 2013 21:11] |
Hauke,
I think there is no need for a new name, since it's just a combination of well defined fairy conditions: "Consequent Alsacian Circe".
Thomas
| | | (15) Posted by Kevin Begley [Monday, Sep 2, 2013 09:16]; edited by Kevin Begley [13-09-02] |
@Thomas,
Thank you for the clarification!
I very much appreciate that, and I'm very glad to learn that this very interesting condition was so carefully considered by the author!
And, thank you for informing me that Jean Zeller invented this condition, too (I was not aware)!
He was an exceptionally gifted fairy inventor, and it only makes me more inclined to investigate this rich condition.
But, just so I'm 100% clear, since I am not trying to make any consequential argument -- only to learn the rules of this condition...
If we agree to ignore the retro content of circe exchange, and agree that castling *might* be considered legal under the rules of that condition, then -- correct me if I am wrong -- you are saying that any resultant diagram is only legal if it can be reached by an orthodox proofgame which includes ALL of the hidden aspects of the position (e.g., castling rights, en passant rights, player on the move, and possibly repetition information).
Therefore 1.O-O# is illegal, because you can not reach such a position (with white to castle) -- do I have that correct?
I'm afraid that I am now regretting my choice to show this using circe exchange (which really confuses retro content).
I now have successfully confused myself; and, I worry that I may have confused others...
Either way, I don't exactly see how consequent information would fully mitigate this matter.
For example, suppose the problem depends upon some move being illegal, because the resultant position (with the black player on the move) can not be reached from any orthodox proofgame of n+0.5 moves (though you can reach the diagram from an orthodox proofgame in n-moves).
I'm not aware how consequent impacts such legality considerations (and I'm skeptical that consequent would afford an alternative set of rules, in such cases).
For the record, I have no interest in inventing a cousin version of this -- I have had more than enough headaches in life from such involvement.
I want only to fully understand the nuances of the detailed rules, for the given condition.
Originally, I deliberately sought ambiguous rules, just to be confident that I understood the conditions.
At some point, when rule seeking efforts failed to produce clarity, I began entangling myself in these treacherous vines.
Anymore, I just want a clear path, or an exit. :)
ps: I have struggled with whether it is illegal to castle in Circe Exchange, with less than 32 men on the board. I asked some fairy experts for advice on this very matter, and was informed that there was some concocted interpretation of the rules, which allowed castling, in such circumstances. I wasn't exactly pleased with that (particularly after no detailed elaboration ever materialized), but I did rely upon this interpretation in at least one problem... (which won some commendation, despite the retro issue).
It seems to me that it requires fairy problemists to specify whether a problem is fairy (wherein retro rules are sometimes ignored), or fairy-retro (where retro analysis is part of the problem).
I question whether it is fair to require solvers to guess such information, after republication (outside of the column's genre filter).
| | | (16) Posted by Eugene Rosner [Monday, Sep 2, 2013 19:37] |
thanks everyone on the rules explanation. it made a difference! I would've otherwise gone down a a dark and lonely route!
making some interesting progress here on what is my 2nd AC problem. the problem will be testing, as there are no real programs for these!
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