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MatPlus.Net Forum General Madrasi
 
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(1) Posted by Joost de Heer [Wednesday, Jul 16, 2008 21:20]

Madrasi


Is it enough for a madrasi paralysis for a piece to be guarded by a piece of the same nature, or should the capture be legal?

Case 1:
W: Ke8 Rc7
B: Kd1 Rc6
Circe Madrasi

Is the rook on c6 paralysed or not? White can't capture Rc7xc6[bRa8] because this would be an illegal selfcheck.

Case 2:
W: Kb1 Sg1
B: Kh1 Sf3
AntiCirce Madrasi

Is Sf3 paralysed or not? Sg1xf3 is an illegal move under AntiCirce.

Case 3:
Is Madrasi + Captureless chess possible?

My personal answers:
1: Yes, Rc6 is paralysed.
2: Yes, Sf3 is paralysed.
3: Yes, this is possible.
 
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(2) Posted by Thomas Maeder [Wednesday, Jul 16, 2008 22:53]

 QUOTE 
Is it enough for a madrasi paralysis for a piece to be guarded by a piece of the same nature,

Yes.

 QUOTE 
or should the capture be legal?

[I assume that you mean: should it be legal without Madrasi]
No, that is not necessary.

 QUOTE 
Case 1:
W: Ke8 Rc7
B: Kd1 Rc6
Circe Madrasi

Is the rook on c6 paralysed or not?

Of course it's paralysed or not :-)

Serious: it *is* paralysed.


 QUOTE 
White can't capture Rc7xc6[bRa8] because this would be an illegal selfcheck.

True, but irrelevant.

 QUOTE 
Case 2:
W: Kb1 Sg1
B: Kh1 Sf3
AntiCirce Madrasi

Is Sf3 paralysed or not? Sg1xf3 is an illegal move under AntiCirce.

Paralysed

 QUOTE 
Case 3:
Is Madrasi + Captureless chess possible?

Yes.

 QUOTE 
My personal answers:
1: Yes, Rc6 is paralysed.
2: Yes, Sf3 is paralysed.
3: Yes, this is possible.

We agree.
 
 
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(3) Posted by Juraj Lörinc [Wednesday, Jul 16, 2008 22:57]

I would say there is difference between captures that are illegal because of self-check (like case 1) and captures that are physically impossible (like case 2).

In the first case White could theoretically make the move.

In the second case it is not possible to make capture. The paralysis should be one-way only in that case, in my view.
 
   
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(4) Posted by Jacques Rotenberg [Thursday, Jul 17, 2008 12:47]; edited by Jacques Rotenberg [08-07-17]

After WChloe (Christian Poisson) you have

1: Yes, Rc6 is paralysed.
2: no, Sf3 is not paralysed.
3: Yes, this is possible. It means in Madrasi+captureless, the Madrasi is like in orthodox

It goes like Juraj wrote, in captureless chess the captures are seen as possible, and forbidden, for example a King can be checked

I feel it is very natural to do so
 
   
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(5) Posted by Thomas Maeder [Friday, Jul 18, 2008 18:15]

 QUOTE 
I would say there is difference between captures that are illegal because of self-check (like case 1) and captures that are physically impossible (like case 2).

I don't see a reason why Anticirce should take precedence over Madrasi. Other conditions, such as Maximummer, don't either.

Therefore I consider
 QUOTE 
2: no, Sf3 is not paralysed.

a programming error.
 
   
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(6) Posted by Joost de Heer [Friday, Jul 18, 2008 19:20]

- If you accept that the AntiCirce case is not a paralysis, then you have to accept that Madrasi+NoCapture is nonsense (NoCapture is Rex Exclusive, so only Madrasi RI would work, and only kings can paralyse each other).
- How does MarsCirce + Madrasi work? Is the paralysis line the orthogonal line, or the line from the Circe rebirth square? I.e. is a black Bd2 paralysed by a white Bc7? Or is a black Bh2 paralysed by a white Bc7?
 
   
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(7) Posted by Juraj Lörinc [Friday, Jul 18, 2008 20:14]

I like the way Joost has set the questions and the way he has answered. His personal answers. I have given only my view too. No single view is definitive in this case unless it is carved into stone and generally accepted.

Maximummer as limiting condition selecting specific move(s) from the set of all possible without maximummer is naturally different from conditions changing rules. Maximummer is thus applied as the last condition by convention.

However precedence of conditions changing rules has usually not been defined and if they do interact (unlike e.g. Circe and Madrasi that do not interact and the combination is without problems), some rule has to be chosen by author.

Whenever in doubt, my preferred approach to Madrasi is as follows. I look at the position how it would work without Madrasi and which captures are physically possible (even if leading to selfcheck). Whenever piece A of type X may capture opposite piece B of the same type X, I consider piece B paralyzed by piece A when adding Madrasi.

This works well with "orthodox" Madrasi, Madrasi with fairy pieces as well as Madrasi with other fairy conditions. If I would have to consider Madrasi first, I would stipulate the precedence.

Madrasi combined with No Capture is not nonsense in this approach, just there would be no paralysis.

Mars Circe with Madrasi would work exactly as you have described in the first case. Paralysis line (usually one-way) leads from Circe square of capturing piece, wBc7 would paralyse bBd2.
 
   
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(8) Posted by Vlaicu Crisan [Saturday, Jul 19, 2008 20:43]

I agree with Juraj's point of view, which seems logical to me (Madrasi paralysis is seen as a result of possible capture, not a trivial orthodox observation). Unfortunately Popeye does not seem to have the same approach when considering Madrasi in combination with other fairy conditions, but that's an entirely different story.

I think we should carefully consider Madrasi in combination with other genres. In certain situations, when Madrasi is used in combination with Koeko, Maximummer, AntiCirce or even neutral pieces, it is possible to have only one-way paralysis.

Some years ago Harmonie organized its 12th TT dedicated to Madrasi problems showing this special effect of "Halb Laehmung" (i.e. partial paralysis instead of ordinary mutual paralysis). The judge of the tourney was Hans Gruber and his judgment can be found at http://www.problemschach.de/harmonie/thematur/tt12.pdf.

My question is: should we throw away all these problems because of a "composing error"? Or are we going to repeat the same scenario as in the Republican Chess thread (with pros and cons)?
 
   
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(9) Posted by Jacques Rotenberg [Sunday, Jul 20, 2008 00:47]; edited by Jacques Rotenberg [08-07-20]

Let us try to be slow and clear

1) It seems natural to see Madrasi as a capturing matter and to say that a piece (of nature X) gives Madrasi effect -paralysis- (to a piece of same nature) if, without Madrasi it could capture.

2)
"Case 1:
W: Ke8 Rc7
B: Kd1 Rc6
Circe Madrasi

Is the rook on c6 paralysed or not? White can't capture Rc7xc6[bRa8] because this would be an illegal selfcheck."

Here also I can give only a "natural" way of understanding, and not an "objective" one. It seems natural to say "because there is a possibility in circe -when there is no selfcheck- to consider the capture Rc7xc6, then this move has to be seen as possible, and the Madrasi condition therefore is effective." The fact that due to other properties of the peculiar position, this move is forbidden does not change the view.

To say it in other words : Would be a bK on c6 it would be checked! it says that this capture has to be considered. It says that Madrasi effect can be here.

This seems to be homogeneous with Madrasi orthodox where a pinned piece has Madrasi power though the peculiar capture would induce a selfcheck and therefore would be illegal.

However, in the different opinions, it seems that everyone agree here.

In the meantime, I could accept a theoretical conception that would say that because the peculiar capture is not legal, the piece cannot Madrasise.

3)
"Case 2:
W: Kb1 Sg1
B: Kh1 Sf3
AntiCirce Madrasi

Is Sf3 paralysed or not? Sg1xf3 is an illegal move under AntiCirce"

Let's go on with the same "natural test" : would be a bK on f3 it would not be checked! -as long as b1 is occupied-
So again the "natural" answer seems to be "the Sf3 is not paralysed"

You can see that as an intercepted piece in orthodox : a wRh3 with something on g3 cannot Madrasise a bR on f3, because it does not reach it. In Anticirce it is as if the way for the wS from g1 to f3 goes trough b1 : You can see it as an interception, the wSg1 is intercepted by the wKb1 to f3!

4)
"Case 3:
Is Madrasi + Captureless chess possible?"

let's take the same position as case 2 :
W: Kb1 Sg1
B: Kh1 Sf3
and let's apply the same test : a bK on f3 would, yes, be checked! -cause in no capture chess, checks a considered as effective!- so the capture on f3 is theoretically possible and therefore the Sf3 is Madrasised!

But would you ask the question with powerless pieces that don't capture at all, even check they do not give, the answer would be else. In the same position but with powerless Knights, you can apply the test and answer : a bK on f3 would not be checked, therefore there is no Madrasi effect.

5)
In Mars-circe + Madrasi, in Maximum + Madrasi, I go on and apply the same test

6)
I, of course, admit that this is by no mean mandatory or obligatory to understand things that way. In all the cases where a common agreement is not accepted, the best way seems to specify the choice of the author with the stipulation.

7)
It is very interesting to see how "simple" questions can induce passionate discussion and disclose unsuspected gaps of opinions
 
   
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(10) Posted by Joost de Heer [Sunday, Jul 20, 2008 11:26]

I've always interpreted Madrasi as 'paralysation by observation', not as 'paralysation by threatening to capture'. With this interpretation, in the AntiCirce example, Sf3 is paralysed, because it's observed. Madrasi+NoCapture is possible with this interpretation too.

For most cases, the observation starts from the square the piece is on, but for some cases (e.g. MarsCirce, there are probably more), the start-of-observation square is a different one (MarsCirce: The circe rebirth square is s-o-o square).

Another example: Do two bishops on a8 and b7 in gridchess paralyse each other in Madrasi? With the observation interpretation: yes. With the capture interpretation: no.

The following composition started a discussion in feenschach, on how Madrasi+NoCapture works, and on how Madrasi+MarsCirce works:

9224 - Joost de Heer
feenschach 158
(= 2+1 )

h=2** MarsCirce, Madrasi, NoCapture

1. .. b7 2. e1=Q+ b8=Q=
1. .. b7 2. e1=R+ b8=R=
1. e1=B b7 2. Bd2 b8=B=
1. e1=S b7 2. Sf3 b8=S=
Babson
 
   
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(11) Posted by Thomas Maeder [Sunday, Jul 20, 2008 11:32]

Rather than arguing the pros and cons of different interpretations, I'd like to find out how Madrasi was originally defined.

Can anybody dig up the original definition?
 
 
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(12) Posted by Jacques Rotenberg [Sunday, Jul 20, 2008 11:46]; edited by Jacques Rotenberg [08-07-20]

I think that your idea of "observation" is not so clear as it seems at first.
When does a piece "observes" another ? What is your criterion ?
 
   
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(13) Posted by Joost de Heer [Sunday, Jul 20, 2008 12:12]

Observation is similar to capture, without the actual capturing (and involved effects, like rebirths).

But I agree with Thomas. I actually had that question in my previous reply, but cut it out for some reason.
 
   
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(14) Posted by Jacques Rotenberg [Sunday, Jul 20, 2008 12:46]; edited by Jacques Rotenberg [08-07-20]

I agree that searching for origins maybe helpful, but it maybe also helpless, and may be disappointing...

In any case the idea of Madrasi is clear enough as is, for common sense. But it seems that sometimes simple common sense is not enough.

Joost, you say ;

"Observation is similar to capture, without the actual capturing (and involved effects, like rebirths)."

what is the difference between this wording, and "possibility of checking" that I use ?

I repeat the very short and simple test - criterion - I propose :

"...a piece A controls (observes, threatens...) a piece B of same nature. Would the piece B be a King (same colour as B) would it be checked by the piece A - without Madrasi - ?
- if yes B is paralysed (Madrasised)
- if not B is not paralysed (Madrasised)"
 
   
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(15) Posted by Joost de Heer [Sunday, Jul 20, 2008 16:13]; edited by Joost de Heer [08-07-20]

In fairy forms where checks are 'fairy' (e.g. UltraMaximum, AntiCirce) there is a difference between observation and check. Furthermore, your definition isn't complete for several RI forms (e.g. Circe RI).
 
   
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(16) Posted by Jacques Rotenberg [Sunday, Jul 20, 2008 16:42]; edited by Jacques Rotenberg [08-07-21]

I think it works also for Madrasi Rex Inclusive (RI) cases. It may work well also with Ultramaximum with a Madrasi effect that may not last and may be nicely intricate.
For Circe Rex Inclusive and other fairy forms that change the usual meaning of check, you are right, I agree that the test I propose "as is" may be not enought.... well, so the composer that will get to those fields will tell us how he wants it to work!
 
   
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(17) Posted by Vlaicu Crisan [Sunday, Jul 20, 2008 21:08]

The Madrasi debate "threat vs. observation" is not new. In Problem Paradise 40/2007, I wrote the following comments, which I think are worth quoting here.

F315 and F316 feature an interesting duo, based on different interpretation of observation under Madrasi condition. While in F315 the observation is interpreted as "simple guard of field", in F316 the observation is interpreted "possibility of capturing on that field". Intriguing, that's why the solution in F316 b) is quite different from the solution from F315 b)! Even chess solving problems will give different verdicts: Popeye solves F315 but not F316, while WinChloe is able to solve F316, but not F315!

This situation escalated a dilemma based on the obvious question: which program is right? In the end, as Hans Gruber rightly suggested, "because it is not a matter of logic here, but of definition, and because there is no legal power to force one of the programmers to change his program, we should take it pragmatically and to note as a composer the program used for testing".

And here are the above mentioned problems:
F315 - Peter Harris (C+ Popeye)
(= 3+7 )

H=3.5
A) AntiCirce Isardam
B) AntiCirce Madrasi
Lions a7, a8, b2, c2, d2, g2, g7, h2
a)1...LIa3 2.LIa2 LIh1 3.LIgc2 Kb3+ 4.LIca4 Kc2=
b)1...Kb3+ 2.Kb1 Kxc2(>Ke1) 3.LIa1 Kxd2(>Ke1) 4.LIa2 Kd1=

F316 - Peter Harris & Guy Sobrecases (C+ WinChloe)
(= 3+7 )

H=3.5
A) AntiCirce Isardam
B) AntiCirce Madrasi
Lions a7, a8, b2, c2, d2, g2, g7, h2
a)1...Ka4 2.LIg7 Ka3 3.LIg8 Kb3+ 4.LIc7 Kxc2(>Ke1)=
b)1...LIa5+ 2.LIa2 LIg5 3.LIg6 Lib5 4.LIb7 LIb8=
 
   
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(18) Posted by Jacques Rotenberg [Monday, Jul 21, 2008 08:31]; edited by Jacques Rotenberg [08-07-21]

..."..."because it is not a matter of logic here, but of definition, and because there is no legal power to force one of the programmers to change his program, we should take it pragmatically and to note as a composer the program used for testing"..."...

I am not sure it is so, perhaps, in fact, as Thomas suggested it there is or in Popeye or in Chloe an error, or an error of logic.

I tried to explain as I could the logic I could understand on the side of Chloe, and to show how it can be seen as a "natural" way of understanding. Now let's have a look at the Popeye side...

It seems to me that it is a good occasion to enter deeper into the question.

I must say that I did not understand very well how it works in Popeye, I tried different possible rules, but each time there are exceptions.

So I would much appreciate to be explained how it works. Perhaps, Thomas, will you agree to spend a little time for that ?

Thank's a lot.
 
   
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(19) Posted by Siegfried Hornecker [Monday, Jul 21, 2008 10:42]

The best thing (for programmers) would be to define Madrasi type A and Madrasi type B with one of these the standard type A and the other type B. So both kinds could be solved. Of course, the composer would have to give "type B" in the stipulation if it matters, giving a big hint to solvers.

Best,
Siegfried
 
   
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(20) Posted by Frank Richter [Monday, Jul 21, 2008 12:52]

As far as I know, the original definition of Madrasi speaks only about the "guarding in orthodox sense" as condition for the paralysis, and there is nothing to read about the possibility of capturing. So I think, the given "tricky" interpreting of the rules is not in the meaning of the innovator and should be labeled by another term as a simple "Type B".
 
 
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