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| (1) Posted by Juraj Lörinc [Wednesday, Oct 15, 2008 21:15] |
Pin-unpin themes
I am just studying twomover themes with dynamic pins. I have noticed there is quite messy terminology here in the area of Schor theme. My two sources even name the same theme by two different names.
According to theme definitions from WinChloe:
Schor - The key selfpins A and unpins a. a unpins A which mates.
Hassberg - The key selfpins A and unpins a which directly selfpins and unpins A which mates.
Mai 1 - The key selfpins A and unpins a. a unpins A which mates using the pinning of a.
Dragoun's Dictionary does not differ considerably.
Given all this, both Hassberg and Mai 1 include Schor, but additionaly require selfpin of a. Mai 1 seem to include Hassberg, but requires use of pin of a in the mate. I.e. any Mai 1 is also Hassberg and Schor, and any Hassberg is also Schor.
Am I right? What are similar, but substantially different themes?
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| (2) Posted by Michael McDowell [Wednesday, Oct 15, 2008 21:37]; edited by Michael McDowell [08-10-15] |
The definition of Hassberg seems to differ from that in Edgar Holladay's book "Hassberg Ingenuity". For example, the following is described as doubling the theme, though it is not the unpinned black piece which moves:
E.M.Hassberg
HM Washington Star 1942
 (= 9+9 )
Mate in 2
1.Qxc3 (>2.Sf2)
1...Qb1 2.Qe3
1...Qxe7 2.Qxc2
Holladay writes "Alain White named one of the pin-unpin restoration themes after Eric Hassberg. In the Hassberg theme the unpinning of a black man and the pinning of a white man are later reversed."
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| (3) Posted by Frank Richter [Thursday, Oct 16, 2008 13:54]; edited by Frank Richter [08-10-16] |
I compared the given definitions with Sidler's compendium "problemschach".
Schor is absolutely identically described.
Hassberg is given with a switchback of A:
E.M. Hassberg
O Xadrex 1946
 (= 10+8 )
#2
1.Q:d3! (2.R:c4#) Q:c3 2.Qd4#
Mari I (not Mai!): The key unpins A and selfpins B (A and B both are white pieces!). Black pins A and unpins B for mating move.
So here is clearly a difference to Chloe.
Another similar theme is Rupp: The key pins a white piece A and a black piece a. The black move unpins both A and a.
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| (4) Posted by Juraj Lörinc [Thursday, Oct 16, 2008 14:56] |
Dragoun's dictionary gives Hassberg theme with switchback as Hassberg II theme, if I remember correctly (I have not it by hand now,but I hope to remember it well). Also James Quah has shown me a few examples of Hassberg theme where the switchback was not required.
WinChloe definitions are available on the WWW as I have just remembered: http://winchloe.free.fr/themes.html
From my point of view the following are "interesting" there:
030 Anti-Rupp
193 Dalton
194 Dalton inverse
317 Hassberg
399 Michel
401 Monreal-Peugeot
665 Mai 1
676 Bograd
680 Castellari
692 Monitor
694 Servais
By the way, isn't there missing a white bishop in the diagram? wBe1 perhaps?
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| (5) Posted by Paz Einat [Thursday, Oct 16, 2008 15:12] |
WBd2 seems to be missing and the threat should be 2.R:c4#
Having these as "themes" looks unnecessary to me, and the mix up in definitions strengthens this point.
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| (6) Posted by Joost de Heer [Thursday, Oct 16, 2008 15:15] |
Threat in Hassbergs composition is 2. Rc4# and not 2. Rb3#.
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| (7) Posted by Frank Richter [Thursday, Oct 16, 2008 15:20] |
You are right, I corrected the position and solution (but the wrong threat in Sidler remains...).
The Dalton definition in WinChloe is analogue to Sidler.
From the other themes I found only Servais:
The key unpins white piece A and black piece a and creates a black and a white halfpin. Black moves every piece from the halfpin for defending the threat. White mates using the pin of the other black pieces with alternating moves by the halfpinned pieces.
I hope, my poor translation is understandable.
In generally, a lot of these "themes" are very mechanical and there are often only one or two working schemes.
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| (8) Posted by Juraj Lörinc [Thursday, Oct 16, 2008 16:15] |
Of course, my interest is not limited to the orthodox field. :-)
I am fully aware of the fact they are usually not very flexible and the names of composers are names for themes is usually making the whole terminology very messy. I prefer the systematic terminology, more in the scientific tone (like that of B. Formanek and J. Brabec for twomovers with changes). Is there anything like that terminology in the pin themes area?
From less used part of my memory I remember an article by F. Abdurahmanovic in feenschach dealing with dynamic pin creation in h#2, where all pins were described by elements for the pin formation. A pin bK - bX - wL can be formed and made active by
A. arrival of bK on the pin line
B. arrival of bX on the pin line
C. arrival of wL on the pin line
D. departure of other black piece from the pin line
E. departure of other white piece from the pin line
The article has shown (if I remember correctly) all combinations of these elements with at least two of them present, in h#2. Of course, 1., 2. and 4. together was impossible in h#2. :-)
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| (9) Posted by Hauke Reddmann [Thursday, Oct 16, 2008 16:20] |
But you can have a move along the pin-line,
which so to say is simultaneously 2 and 4 :-)
Hauke
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| (10) Posted by Michael McDowell [Tuesday, Oct 21, 2008 09:48] |
Is there a theme name for the following two-move idea?
The key pins a white piece A.
The threat pins a black piece B.
Black's defences are anticipatory unpins of B, but also unpin A, which then mates.
T.R.Dawson would have entirely agreed with Juraj about the messiness of much terminology. Someone would do the problem world an immense service if they made his book "Systematic Terminology" available on the web. His scientific approach to the classification of themes was decades ahead of its time.
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