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MatPlus.Net Forum General proper name of theme?
 
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(1) Posted by Eugene Rosner [Sunday, Oct 4, 2015 22:38]

proper name of theme?


In the solution of a directmate #2 the variations line up this way...
1...a 2.A,B,C
1...b 2.A,B
1...c 2.A

other than "mate reduction" does this have a name?
 
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(2) Posted by Ian Shanahan [Monday, Oct 5, 2015 04:39]

In Rice, Lipton and Barnes's book "The Two Move Chess Problem: Tradition and Development", this is labelled as "Progressive Separation". That name has been established for about 50 years. However (as one who has worked a lot with separation themes)...

If A, B and C are threats (primary or secondary), then I'd call it "Progressive Separation";

But if they're not threats, but simply duals, then "Mate Reduction" seems more appropriate.

When some of ABC are threats, some duals, go with the majority. Years ago, I composed a problem where three primary threats were separated combinatively (i.e. seven variations), but a random move by a particular Black piece defeated all three primary threats yet lead to a progressive separation of five new mates - four of which were secondary threats, but not the fifth. So I went with the moniker "Progressive Separation".

I hope this helps, Eugene.
 
 
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(3) Posted by Eugene Rosner [Thursday, Oct 8, 2015 15:24]

many thanks Ian-
I also found an example in JMR's new ABC!
 
 
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(4) Posted by shankar ram [Friday, Oct 9, 2015 03:42]

Ian, could you post your problem here?
I can't recall seeing any example of a combination of combinative AND progressive separation!
 
   
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(5) Posted by Hauke Reddmann [Friday, Oct 9, 2015 22:20]

Seconded.
 
   
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(6) Posted by Geoff Foster [Saturday, Oct 10, 2015 00:00]

This seems to be the problem.

Ian Shanahan
(dedicated to Michael Lipton)
The Problemist 1998
(= 9+8 )
#2

1.Qxd6! (>2.Qd4,Qd5,Qxe5)
1...Sb7 2.Qd4,Qd5,Qxe5
1...f6 2.Qd4,Qd5
1...Qxg4 2.Qd4,Qxe5
1...Sb3 2.Qd5,Qxe5
1...Saxc4 2.Qd4
1...Sac6 2.Qd5
1...gxf5 2.Qxe5
1...Sf3 2.gxf3,Qxf4,Rxf4,Bxf3,Bd3
1...Sec6 2.Qxf4,Rxf4,Bf3,Bd3
1...Sexc4 2.Rxf4,Bf3,Bd3
1...Sd3 2.Bf3,Bxd3
1...Sxg4 2.Bd3

This also shows the Dalton theme (key unpins a black piece which then pins the key piece)!
 
   
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(7) Posted by shankar ram [Saturday, Oct 10, 2015 05:52]; edited by shankar ram [15-10-10]

Very fine problem, Ian!
Primary combinative separation of 3 threats and secondary progressive separation of 5 threats. Plus the Dalton theme!

You say "...four of which were secondary threats, but not the fifth..."
I think think you're referring to 2.gxf3#? Only 1...Sf3 contains the weakness allowing this particular mate.
This IS a tricky question! Depends on the exact definition of "secondary progressive separation".

The combinative expert, Gerhard Maleika has a series of problems in which there is a mixture of both primary and secondary mates in the combination. So, perhaps, your case could also be treated similarly.
 
   
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(8) Posted by Ian Shanahan [Wednesday, Oct 14, 2015 07:07]

Thank you, Shankar. Yes, 2.gxf3# is NOT a secondary threat - because it is entirely reliant upon a specific arrival effect (i.e. occupation of f3).

I know the Maleika problems to which you refer. If I recall correctly, you yourself wrote an article titled "Duals Galore!", which was published in "The Problemist" during the 1980s; Maleika himself presented even more examples within a lengthy article in "Themes 64"(?), 1989(?). Anyway, I think the best ones are those that combinatively separate 3 primary threats and 3 secondary threats. (The Velimirovic Encyclopedia - which I don't have immediately to hand - calls this the "Maleika Blend", if memory serves.)
 
   
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(9) Posted by shankar ram [Wednesday, Oct 14, 2015 19:55]

Yes, Ian! I did write that small article. It was more a quick compilation of Maleika's mind numbing achievements in this field.

As you might know, T.R.Dawson composed the first example, to illustrate primary and secondary defence mechanisms, during the course of his "Systematic Terminology" series of articles in the B.C.M in the late 1940s. Soon A.R.Gooderson composed the first 4 fold example, which was also published at the same time, in the B.C.M. I think TRD would have been astonished and happy to see the way Maleika has carried forward the theme.

I dream of a 5-fold example, with 31 variations..! Should be possible in a fairy setting. (Don't know if Maleika's already done it!).
 
   
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(10) Posted by Hauke Reddmann [Wednesday, Oct 14, 2015 20:57]

In a fairy setting it's fairy...eh, fairly trivial.
Just set up proper combinations of leapers and
solve the resulting diophantine equation :-)
(In this way I once set up a super-carousel or what the
cycle is named, but it didn't make it to Cyclone...
rightfully. :-)

32 variants...compare with the record for variants
(looked up in the handy Morse, of course)
without conditions. Impossibru!

Hauke
 
 
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(11) Posted by Ian Shanahan [Friday, Oct 16, 2015 18:10]; edited by Ian Shanahan [15-10-19]

Yes, Shankar, I'm well aware of the origins and history of combinative separation [c.s.]. Edgar Holladay was an early proponent of such themes too. There was a theme tourney conducted for them in an American publication ("Cleveland Plains Dealer"?) in 1948, with Holladay as the judge. In the early 1960s, the now long-defunct Italian magazine "Il Due Mosse" conducted another theme tourney in 1962 from which emerged the Mentasti theme (cyclic pairs of duals). In fact, a few years ago, the late Christopher Reeves - who composed a fantastic 4-fold c.s. where all the Black defences were Pawn moves, including double AUW(!), and who wrote a seminal article, "Multiple Play in the Two Mover" ("The Problemist", September 1970),* which discusses the history of 'thematic duals' - sent me the award to both tourneys, as well as correspondence on the theme from Holladay and A. R. Gooderson. Of course, I treasure these primary sources. Gooderson, moreover, was the first to compose an example of changed (secondary) 3-fold c.s., an astonishing achievement - 1st Pr, B.C.M. (1966). At present, Maleika and I seem to be the only composers still actively pursuing the theme. My only original contribution to the evolution of c.s. are several examples of 3-fold c.s. blended with Black correction - see a brief article about this in "MatPlus" (1997), called "Black Intelligence", for examples - something I hope will eventually become known as the "Shanahan Blend" (as a cousin to the "Maleika Blend"). Finally, nobody has succeeded in composing a 5-fold example of c.s. - orthodox or Fairy - and I'm inclined to think that that task is impossible. But I'd love to be proven wrong!

* A PDF of this issue can be downloaded from the BCPS website, if you are a member of the BCPS.
 
 
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MatPlus.Net Forum General proper name of theme?