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MatPlus.Net Forum Helpmates Is this symmetry a flaw?
 
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(1) Posted by Marcos Roland [Wednesday, Nov 28, 2007 00:19]

Is this symmetry a flaw?


This is one helpmate I composed in the late eighties.

Marcos Roland
UBP 1990(?) Commended

(= 5+7 )

h#3 2.1.1.1.1.1.

To see the solution, drag the mouse over here: a)1.Bc5 Bf2 2.Re3 Sb4 3.Kd4 Sf3# b)1.Bf5 Bc2 2.Rcd3 Se2 3.Ke4 Sc3# .

So, I'd like to propose two questions: i) is this problem, total or partially, symmetrical? ii)if so, is this symmetry a serious flaw?
 
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(2) Posted by Harry Fougiaxis [Wednesday, Nov 28, 2007 10:23]

There is a certain feeling of symmetry here, but imho it is not so disturbing. Personally I would be more concerned by the following inaccuracies :

1. In the second solution, there is no critical move by the Bd3 like in the other solution.
2. In the second solution, Black can choose which rook to move to allow the king step forward and he should be careful not to unblock a flight, while in the first solution there's no such an option.
 
 
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(3) Posted by Marcos Roland [Wednesday, Nov 28, 2007 12:47]

Thank you, Harry, for your comments. About the flaws you mentioned, as far I remember, I was aware of them,specially the second one, but didn't overcome the constructional difficulties: too many cookies in the diferent versions I tried to express the original idea.
 
   
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(4) Posted by Jacques Rotenberg [Wednesday, Nov 28, 2007 17:56]; edited by Jacques Rotenberg [07-11-28]

I do like this problem very much, it can be described as follow :

- Chameleon-Echo model mates
- Umnov-Mates
- h3# with 4 white pieces are not frequent
- The construction is successful and light
- The critical move in one solution is balanced by the choice of the Rook in the other one
 
   
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(5) Posted by Harry Fougiaxis [Thursday, Nov 29, 2007 00:52]

I myself like it too, but the construction is not so successful. You see, it's quite easy to save the bQ and one of the bishops at the cost of a pawn. Apart from that, it is a sweet problem.
 
   
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(6) Posted by Jacques Rotenberg [Thursday, Nov 29, 2007 07:42]

you mean something like that ? :

(= 5+6 )


but you lose on the quality of the echo, so I could understand that the author wants to keep the two Bishops
 
   
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(7) Posted by Harry Fougiaxis [Thursday, Nov 29, 2007 11:01]; edited by Harry Fougiaxis [07-11-29]

Yes, with a black pawn on c7 instead of the knight. To my eyes, the echo move by a second bishop is visual dressing only and not so important. In fact, I would have preferred to have a single black unit carrying out the self-blocks @B1, but it seems not to work with the queen on c8 or f8 (without additional material.)
 
   
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(8) Posted by Jacques Rotenberg [Thursday, Nov 29, 2007 11:25]; edited by Jacques Rotenberg [07-11-29]

Ok, you are right Harry, even if you want to keep the Bishop you can save the Queen :

BBa7 instead of the Knighta6 (and then put the BBg6 in h7 for visual effect)
 
   
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(9) Posted by Marcos Roland [Thursday, Nov 29, 2007 11:37]

Have you computer checked these proposals?
 
   
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(10) Posted by Jacques Rotenberg [Thursday, Nov 29, 2007 11:47]

yes
you can also choose a twin form :
with only one Bishop
a) BBb6
b) BBg6
 
   
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(11) Posted by Marcos Roland [Thursday, Nov 29, 2007 11:53]

At the time, I didn't think of twins, but, now considering, that would be nice indeed.
 
   
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(12) Posted by Jacques Rotenberg [Thursday, Nov 29, 2007 12:11]

I don't know at all
this kind of question is very difficult for me : to choose or twins or not twins
 
   
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(13) Posted by Marcos Roland [Thursday, Nov 29, 2007 16:01]

Jacques, in your version with twins, is there a black pawn on a5?
 
   
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(14) Posted by Jacques Rotenberg [Thursday, Nov 29, 2007 22:55]

yes in both twins you need it, to prevent a mate with the King on place and 3.Sb4#

However finally I think it is better without twins
 
   
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(15) Posted by Paz Einat [Friday, Nov 30, 2007 23:24]

Guys, the "twins" issue is semantic. Even without twins it is clear that one bishop is not needed in each solution. In such a case I think it is better to use twins.

At any rate, the problem is really nice!
 
   
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(16) Posted by Marcos Roland [Saturday, Dec 1, 2007 01:13]

I found an aristocratic version:

(= 5+4 )

h#3

b)BBh6
 
   
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(17) Posted by Jacques Rotenberg [Saturday, Dec 1, 2007 20:26]

Very nice Marcos! Now you have no plug at all.
Still I think that with the 2 Bishops and 2 solutions it is slightly better.
The main reason is because it is much more comfortable to solve : only one position.

In any case, this new version is worth a publication, I think.
 
 
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MatPlus.Net Forum Helpmates Is this symmetry a flaw?