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MatPlus.Net Forum General Isardam and en passant
 
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(21) Posted by Michel Caillaud [Sunday, Dec 19, 2010 22:50]

I made the same search in PDB and found 5 more problems, all by Nikita Plaksin, all with "Last move?" stipulation (different Isardam types...). So ??
 
 
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(22) Posted by Kevin Begley [Sunday, Dec 19, 2010 22:52]; edited by Kevin Begley [10-12-19]

On PDB (not Win Chloe) there are 8 problems which are returned by the search: K='isardam' and sol='ep'

One is the excellent problem by Juraj -- which you already mentioned.
At first glance, it seems this one does not apply; however, what is the the bPf5 doing here?
Perhaps I am overlooking another function of this pawn, but it seems to me it prevents an en passant capture in Isardam.
That is, by explicitly eliminating the retraction (-1...e2-e4??), it prevents any claim of cook (by en passant).

The other 7 are last-move retros, by two composers, which actually do play an en passant capture (in Isardam).

Either these two composers are mistaken (and their problems are unsound), or they aim here to express an ambiguity in the rules.
[or perhaps they have invented a new form of Isardam.]
 
   
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(23) Posted by Kevin Begley [Sunday, Dec 19, 2010 23:01]; edited by Kevin Begley [10-12-20]

>I made the same search in PDB and found 5 more problems, all by Nikita Plaksin, all with "Last move?" stipulation (different Isardam types...). So ??

There are 5 by Nikita Plaksin, and 2 by Arno Tüngler...

So... are these unsound? are they exploiting a loophole in Isardam rules? are they a new form of Isardam?
[Is the bPf5 necessary in Juraj's problem (or an extra)?]

Can anyone really say for sure?

It would be nice if a Fairy Rules Council (appointed by WFCC) could say what is definitely legal, what is definitely illegal, and what is currently ambiguous (at least for sanctioned fairy elements)... maintain some version control... and suggest how to eliminate ambiguities (pending approval by WFCC delegates).

Do the original rules of Isardam explicitly state whether it prohibits all (or only mutual) types of Madrasi paralysis?
Even if so, it may not be a slam dunk...
After all, A. J. Karwatkar's original Madrasi rules (and problems) proved surprisingly different from our present interpretation.

Original Madrasi Rules:
"When a man, other than a K, attacks an enemy man of the same kind, both men become inert. Hence a capture between equals would be illegal."

So, even in Madrasi, going by the original rules, en passant captures would be illegal -- are the original Isardam rules any better?

For that discussion, see: "http://www.milanvel.net/mp/snapshot/rescbody.php?px=1244212404&fid=gen&tid=377";
The really sad part about it is, here, 28 months later, I'm still saying the same exact thing -- why don't I simply surrender?

"So non-reciprocal Madrasi paralysis, as supported by Popeye and (probably) other solving programs, doesn`t conform to the original Madrasi. Ouch!"
-Thomas Maeder.
 
   
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(24) Posted by Juraj Lörinc [Monday, Dec 20, 2010 13:49]; edited by Juraj Lörinc [10-12-20]

In my Valladao retro, bPf5 is needed especially in the Patrol Chess phase. It prevents the last move Be4-a8+.
 
   
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(25) Posted by Kevin Begley [Monday, Dec 20, 2010 16:24]; edited by Kevin Begley [10-12-20]

@Juraj,

D'oh, of course... I always miss the "obvious" in this cursed Patrol. :)
Lovely problem, though!

hehe... and, who would have guessed that your placement of bPf5 prevents (invalid?) claims of a cook, by an en passant in the Isardam phase!?

@All,

It is probably fair to conclude that en passant captures are illegal in Isardam (unless facilitated by an additional condition).
And, those 7 Isardam problems, showing en passant as the last move, are probably unsound (as is).

Perhaps they should be reclassified as "Mutual Isardam" (where moves resulting in mutual madrasi paralysis are illegal, but non-mutual madrasi parlaysis is OK).
This would seem to offer many interesting possibilities...
 
   
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(26) Posted by Axel Gilbert [Monday, Dec 20, 2010 21:00]

All right,

I shall conclude that en passant (and "move that would lead to an en passant possibily") is forbidden in "standard" Isardam.
And more generally, moves that lead to any one-way paralysis.
Winchloé and old versions of Popeye can C+ problems with this rule.

As for the Xmas tournament, the director (speaking) can verify problems for you if you need.

I guess other conventions are acceptable if stated so (and assuming that they may not by computer-checked)
 
 
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(27) Posted by Michel Caillaud [Monday, Dec 20, 2010 21:05]

Yes, en passant is illegal according to known "rules" (Winchloe or "sound" (=before 4.47) Popeye).
And, yes of course, one can imagine variants of Isardam where it becomes legal.
I cannot speak for the other judge Eric Pichouron, but I will consider them in my section if there are some. That doesn't mean they will be in the award : it is to the composer to demonstrate that the new variant (asking more investment for the judge...) is worth it...
 
   
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(28) Posted by Axel Gilbert [Thursday, Dec 23, 2010 16:24]

Eric Pichouron (judge for the retro section) says he would consider both conventions (the "standard one" and the convention allowing the double-step) for Xmas tournament.
So it's up to you now !
 
 
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MatPlus.Net Forum General Isardam and en passant