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MatPlus.Net Forum General obtrusive force: what say you?
 
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(1) Posted by Eugene Rosner [Wednesday, Jan 16, 2013 15:54]

obtrusive force: what say you?


is it an absolute no-no, or is it perfectly acceptable if a good chess idea cannot be shown any other way? Have attitudes changed on this in recent years? I'm also curious what the new Anthology of Chess Problems has to say on this...
 
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(2) Posted by Sven Hendrik Lossin [Wednesday, Jan 16, 2013 21:08]; edited by Sven Hendrik Lossin [13-01-16]

I think this depends on the editor of the chess column/magazine.

If I were the editor I'd try to figure out if the flaw is justified by the theme.
I have seen a selfmate with a promoted piece recently in feenschach and I think in a magazine like feenschach this should be okay because it is mainly devoted to fairy chess where you would never pose the question if a piece is obtrusive or not.

And boy, editors opinions can differ more than you can figure out. I have sent a helpmate that shows a valladao to two magazines and the first editor said that he does not accept valladaos as this is not a theme in his view. The second editor thanked me for that very funny work.

But you should consider to ask some very good composer if he finds a version without the obtrusive piece.
 
 
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(3) Posted by Kevin Begley [Wednesday, Jan 16, 2013 22:54]

There used to be interesting article on the Israeli Chess Composition Society site (I can not locate it now), with some interesting arguments in favor of obtrusive force (suggesting it be considered a minor flaw, at most).
I don't completely agree, but I found myself wanting to try it.

Obtrusive force is generally considered a very minor flaw (if at all) in fairy problems.
But, in orthodox settings, it can be the difference between a prize, and nothing.

I think your thematic expression (whatever that may be) should be treated as King.
Thus, you may sacrifice anything necessary (material economy, fairy element economy, constructional aesthetics, obtrusive force etc) to save your King (express your idea).

If you overlooked a better construction (e.g., without obtrusive force), you should expect a harsh penalty in judgment.
And, even if your construction proves optimal, the judge must still ask the separate question: is it worthwhile?
The beauty of your expression must be weighted against even the necessary constructional costs.

Judges (particularly those with an orthocentric disposition) commonly fail to ask this question, when it comes to excessive fairy elements -- a mistake which is generally detrimental to fairy problems.
But, they will go overboard addressing obtrusive force.

The real challenge, of course, is trying to weight your sub-optimal tradeoffs.
For example, is obtrusive force worse than a zero-position with 9 extra units?

It would serve us all well -- particularly beginners! -- if detailed consideration were given to cases of various constructional flaws (from the slightest promotion dual, up to, and including, positions which can not be legally reached).
Ideally, each case should offer both a scheme to demonstrate the flaw's severity, and a problem to demonstrate that the flaw is less than absolute.
 
   
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(4) Posted by Sven Hendrik Lossin [Wednesday, Jan 16, 2013 23:00]

For those who understand German this might be of interest:
http://www.berlinthema.de/legal.htm
 
   
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(5) Posted by Kevin Begley [Thursday, Jan 17, 2013 12:04]; edited by Kevin Begley [13-01-17]

Interesting article (though probably much better if I didn't have to suffer through google's universal translator).
So that's why Lieutenant Uhura had to study foreign languages!

Walther von Holzhausen
version C.S.Kipping
Akademische Schachblätter 1901
(version: Salut public 1929)
(= 5+2 )

#2

Forget about absolute constraints -- let's just look at this from a cost standpoint.
Is it cheaper to add more material (to provide black a last move), or is it cheaper to present the problem as retro-illegal?

Does it matter that a leap above 7 units surrenders the status of "miniature."

I think any composer who comes to such a crossroads would feel obliged to look for some way to make good use the additional material necessary to relieve this retro-illegality.
All the while asking: is either remedy worthwhile?

As it relates to the issue of "obtrusive force," just consider adding a black grasshopper at c1.
[note: this is not some version I am proposing, I would advocate against a fairy unit here -- just trying to make a point.]

This adds a variation (albeit with a mating promotion dual -- sigh!), but consider black's last move: must have been a grasshopper promotion onto c1.
Therefore, this would constitute obtrusive force -- agreed?

From a cost standpoint, some infractions do fall onto a definite scale:
Extra legal force (e.g., 10 Bishops of a color, on the same color square) must be worse than promoted force (e.g., 2 Bishops of a color, on the same color square), which must be worse than obtrusive force (e.g., 1 Bishop, which must have promoted) -- right?

So, my question is this: if you must incur obtrusive force, can we say definitively that there are preferred methods to conceal it?
Is structural obtrusiveness not worse than retrograde promotion?
And, should we prefer that the promotion be hidden/evident?
 
   
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(6) Posted by Ian Shanahan [Friday, Jan 18, 2013 00:44]; edited by Ian Shanahan [13-01-19]

Personally, I have no problem with obtrusive force. Since proof-games to many problems are highly unlikely to have occurred in any chess game anyway - and indeed may even have necessarily included promotions whereby the promotees have disappeared (see my recent thread on this topic http://matplus.net/pub/start.php?px=1358465971&app=forum&act=posts&fid=xshowr&tid=1180), this not being regarded as a flaw - it is logically inconsistent to object to obtrusive force ... though, to avoid controversy, if I could circumvent it without extra force or whatever additional constructional pain, I'd do so. I think this is the prevailing attitude nowadays (though I do know of some contemporary problemists with very old-fashioned attitudes on the subject). Force additional to the initial array of men (e.g. 3 wRs or 2wBs on Black squares) are another matter entirely, and in my opinion should be deployed only to show something that is impossible to demonstrate with the standard force.
 
   
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(7) Posted by Kevin Begley [Friday, Jan 18, 2013 07:49]; edited by Kevin Begley [13-01-18]

@Ian,

>"Personally, I have no problem with with obtrusive force."

Your opening statement is not clear -- you regard obtrusive force to be what?
a) Not the end of the world?
b) Not a major flaw?
c) Not even a minor flaw?

I presume you are arguing that obtrusive force should not even be considered a minor flaw.
I don't agree -- obtrusive force should definitely be considered a minor flaw (read: avoid, when possible).
When this flaw can not be avoided (without incurring some other defect, or compromising thematic intent) -- like all unavoidable flaws! -- it should be weighted (holistically) against the thematic expression.
It should be viewed as a cost, which composers should strive to avoid paying.

Furthermore, I don't see any valid support provided for your claim that "...it is logically inconsistent to object to obtrusive force...", nor do I buy your claim that yours is "the prevailing attitude [read: convention] nowadays."

Consider your argument...
First, you make a faulty comparison of two different standards -- standards imposed upon an orthodox forward problem (#n) are not the same as those imposed upon proofgames!
Beyond the changed aim, there is a significant difference between a "help-game-n" and a "help-mate-n" -- the former may may use retro-promotion to stage the backward play, whereas the latter (unless it is a retro) has only a forward component.
Standards of retrograde promotion may be entirely different, for problems with a retro-aspect (this may include proofgames).
Indeed, even the standards for obtrusive- and promoted- force (remaining in the diagram) may be entirely different!

Second, some of your argument is based upon the implicit supposition that retrograde-promotions ("whereby the promotees have [demonstrably] disappeared [from the diagram]") should be considered equivalent to the obtrusive force flaw.
If this were the case, it would also hold for all promoted force in the diagram (beyond that which is based upon obtrusive promotion).

Your "reasoning" here provides little more than a false equivalence -- (promoted force, obtrusive force, and retrograde promotion are not necessarily of equivalent severity).
Units which remain in the diagram, as a product of obtrusive promotion, are not equivalent to promoted units which have been annihilated.
If you want to argue that they should be treated equivalently, nonetheless, you have yet to provide us with any rationale (beyond your subjective favoritism).

If your intent was only to note your personal, subjective preference, I certainly do appreciate your position.
But, it should be clarified that no objective support has been provided.
Also missing is a coherent philosophy which could be used to preclude the extension of this logic.

Is it your intention to suggest that we should, similarly, "have no problem" with any instance of promoted force (in a diagram)?
I wouldn't be entirely displeased to find out I was wrong, but I expect most judges would have a problem with this.

In fact, if "obtrusive force" were generally considered "no problem" (as you suggest), for what purpose does the term still linger?
There are cases where judges have expressly imposed some penalty, for the inclusion of obtrusive force (even when they could not provide an clean remedy).
[note: I don't necessarily disagree with such judgment -- even the optimal construction may be downgraded by the necessary costs of the expression. Unfortunately, judges rarely take the opportunity to clearly explain this point.]

And, whereas an obtrusion may be easily overlooked, this is hardly evidence that the flaw has been embraced as unsubstantial.
Where has this ever been expressly embraced as insubstantial?
 
   
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(8) Posted by Hauke Reddmann [Friday, Jan 18, 2013 12:33]

Kevin wrote: "Where has this ever been expressly embraced as insubstantial?"

Like: in the Kraemer/Zepler book on a problem of Brunner (? - too lazy,
didn't search), where those two giants show a clearly distinctive opinion.
Kraemer (or was it Zepler) says (not literally) "Buggrit, I couldn't care less",
Zepler (or was it Kraemer) says "I do care, at least until I tried myself",
and gives a setting without the obtrusive bishop.

Which is my default approach. (I optimized away smaller blemishes than this one
in other peoples #2...)

Hauke
 
   
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(9) Posted by Sven Hendrik Lossin [Friday, Jan 18, 2013 13:10]; edited by Sven Hendrik Lossin [13-01-18]

I have seen once that the judge noted that the position could only arise by several promotions in the retro play. That was somehow surprising to me.
See P1255258 in the PDB by Safarov, #3, Schwalbe 2005, 3rd commendation.

P.S.
Hauke wrote: (I optimized away smaller blemishes than this one in other peoples #2...)
This is what I meant with "But you should consider to ask some very good composer if he finds a version without the obtrusive piece."
I don't know if Hauke is a "very good composer" since I haven't the slightest idea what the #2 is about but as far as I know him I guess he is a good optimizer.
 
 
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(10) Posted by Kevin Begley [Friday, Jan 18, 2013 13:28]

Hauke,

Your comments seem rather incoherent.

OK, the Kraemer/Zepler book suggests that opinions may differ on this issue.
However, ultimately, doesn't its story suggest that a composer should consider obtrusive force to be a flaw, and TRY to find a way around it (whenever possible)?
That's the moral I get out of it -- and, this agrees completely with my statement.

Obtrusive force is a flaw -- not the end of the world, but a flaw nonetheless; and, one that should be remedied if possible.
You seem to agree with this position yourself -- otherwise, why would you bother to "optimize away smaller blemishes" ??

So, my question remains: Where is it expressly stated that obtrusive force is not a flaw?

ps: and yes, laziness is the mother of increased productivity.
 
   
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(11) Posted by Kevin Begley [Friday, Jan 18, 2013 13:43]; edited by Kevin Begley [13-01-18]

@Sven,

The judge actually penalized this problem (P1255258), because of retrograde promotions?
I see that judge Volker Zipf awarded it only 3rd Commendation (according to Win Chloe).
Unless my eyes deceive me (maybe I'm unaware of forerunners with related thematic content!?), that does seem a very poor judgement.
It baffles me why anybody would want to wrestle with orthodox conventions -- when you can bask in retro-illegal fairies.

ps: If you doubt Hauke's mad Spartan composing skillz, feast your eyes on this:

Hauke Reddmann
Die Schwalbe, 1985
(= 4+1 )

h#6 Grasshoppers (unobtrusive)
 
   
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(12) Posted by Juraj Lörinc [Friday, Jan 18, 2013 16:42]

And do you know what Hauke himself said about the grasshopper position? Voila: http://jurajlorinc.com/chess/dlhm_09.htm#uloha8

By the way I have just checked the solving speed and it took less than 3 seconds instead of Hauke's one day 28 years ago.

(Sorry, if it looks like thread hijacking, I just instantly remembered the position from CCM early years.)
 
   
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(13) Posted by Ian Shanahan [Saturday, Jan 19, 2013 05:09]; edited by Ian Shanahan [13-01-19]

@Kevin. I see no reason whatsoever why obtrusive force prior to the diagram position is in any way fundamentally different to obtrusive force in the position itself. The former (rightly) is disregarded, so logically the latter should be too. Why exactly is obtrusive force present in the diagram regarded as even a MINOR flaw - particularly when promotion in the play is OK? It smacks of double standards. I'd only avoid obtrusive force in order not to be subjected to the adverse criticism of those whose composerly aesthetics are nearly a century old.

"I don't agree -- obtrusive force should definitely be considered a minor flaw (read: avoid, when possible).
When this flaw can not be avoided (without incurring some other defect, or compromising thematic intent) -- like all unavoidable flaws! -- it should be weighted (holistically) against the thematic expression.
It should be viewed as a cost, which composers should strive to avoid paying."

WHY???

"First, you make a faulty comparison of two different standards -- standards imposed upon an orthodox forward problem (#n) are not the same as those imposed upon proofgames!"

You totally miss the point. I'm not comparing PGs with #n at all, but focussing on the proof-game of a #n in deciding the position's legal status. So that comparison IS perfectly valid and indeed NECESSARY!

"Indeed, even the standards for obtrusive- and promoted- force (remaining in the diagram) may be entirely different!"

Yes - I already acknowledged that!

"Second, some of your argument is based upon the implicit supposition that retrograde-promotions ("whereby the promotees have [demonstrably] disappeared [from the diagram]") should be considered equivalent to the obtrusive force flaw.
If this were the case, it would also hold for all promoted force in the diagram (beyond that which is based upon obtrusive promotion)."

That doesn't necessarily follow. The promotees that have disappeared may not have all been present together and may not have called on any units beyond the standard game line-up (i.e. each might have been strictly obtrusive, and not EXTRA 'promoted force').

"Your "reasoning" here provides little more than a false equivalence -- (promoted force, obtrusive force, and retrograde promotion are not necessarily of equivalent severity).
Units which remain in the diagram, as a product of obtrusive promotion, are not equivalent to promoted units which have been annihilated."

Your 'reasoning' here provides little more than a false distinction! You give absolutely no reason as to why obtrusive units present in the diagram should not be considered equivalent to promoted units which were annihilated earlier (and which themselves might be obtrusive).

"If you want to argue that they should be treated equivalently, nonetheless, you have yet to provide us with any rationale (beyond your subjective favoritism)."

I already did! On the contrary, you need to move beyond subjective favouritism and argue why they - disappeared promotees (obtrusive or not) and obtrusive force in the diagram - should be treated differently. You are yet to proffer a valid argument why obtrusive force is a flaw. (That compositional aesthetics from many decades ago happened to regard obtrusive force as such - inconsistently! - is not valid reasoning.)

"Is it your intention to suggest that we should, similarly, "have no problem" with any instance of promoted force (in a diagram)?"

Not at all! And I already said so - as well as WHY. i.e. that blatantly promoted force - beyond the standard game-array - should only ever be used in a #n to show something otherwise unobtainable. (I wrote in my previous post: "Force additional to the initial array of men (e.g. 3 wRs or 2wBs on Black squares) are another matter entirely, and in my opinion should be deployed only to show something that is impossible to demonstrate with the standard force.")

"There are cases where judges have expressly imposed some penalty, for the inclusion of obtrusive force (even when they could not provide an clean remedy)."

They are wrong in doing so - engaging faulty, inconsistent logic!

"And, whereas an obtrusion may be easily overlooked, this is hardly evidence that the flaw has been embraced as unsubstantial."

Again you PRESUME it's a flaw (based on ye olde aesthetic?).

"Where has this ever been expressly embraced as insubstantial?"

In several articles by Edward Beal in "The Problemist" during the 1970s, for starters. In a discussion within a British text about a Loshinsky 1st-Prize-winner from the 1930s with an obtrusive Bishop. And in many modern chess-problem texts I have read (John Rice's "Chess Wizardry" I think?). Comfortable acceptance of obtrusive (as distinct from promoted) force is already nearly half a century old, albeit not universally so!
 
   
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(14) Posted by Kevin Begley [Saturday, Jan 19, 2013 18:03]; edited by Kevin Begley [13-01-19]

@Ian,

Please examine your argument more carefully:

First, you argue that obtrusive force present in the diagram should NOT be regarded "as even a MINOR flaw" because it "smacks of double standards" to hold "promotion in the [forward] play" by a different set of standards (from those which apply to obtrusive promotions appearing in the diagram).

Logically, you are suggesting that any standard which applies to forward play, should also apply to the diagram; yet, you vehemently insist that promoted force in the diagram should be treated by a standard altogether different (from that in the forward play)!

Second, you have argued that the same standard should apply when there is retrograde proof that promoted force must have existed.
If that's the case, then this not only applies to obtrusive force -- it also applies to promoted force!

This is why your double-standards argument falls apart entirely: your logic begs us to treat all promotions equally (forward and retrograde, diagrammed and captured), yet you insist on favoring only obtrusive promotions (and, at a very opportune moment)!

Why must these long held standards suddenly change now?
Where were you on this issue prior to having struggled (in vain) to overcome this flaw, in your own work?

Your second argument is to attack the old standards.
I do entirely sympathize with this argument!
Orthodox standards were long ago crafted to serve practical players (more than to advance the art of chess composition).

You asked me to explain why is obtrusive force in the diagram considered a flaw... you may not like my answer:
Because that's the long enduring standard that people have come to expect from orthodox chess problems!

For the same reason that promoted force in the diagram is considered a flaw, so too is obtrusive force (though the former may be considered more severe).
Why is the standard different for promoted units which were captured?
Because they are DIFFERENT (no longer in the diagram), they can be treated differently!
That's how to standards developed, that's how the standards have endured (all these long years).

Some composers and judges may not deduct at all for obtrusive force.
OK, big deal -- some have argued that promoted force is not a flaw!

I think standards should be reexamined -- but not relaxed in some illogical, artificial fashion.

I submit that two separate standards are fundamentally necessary:
1) For problems where retrograde considerations play some essential role, anything should be accepted (obtrusive force, promoted force, etc) which does not jeopardize the retro-legality of the position.
2) For problems with no retrograde content, anything and everything should be accepted (obtrusive force, promoted force, and yes, even retro-illegal positions).

That's what I'd like to see; and, with standards steadily eroding in that direction, maybe we will get there -- but, until we do, I would prefer that everyone were judged by similar standards.

The constant -- ever timely! -- piecemeal erosion seems to me a deliberate mechanism to inject bias into what is already a beauty contest plagued by rampant favoritism.
 
   
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(15) Posted by Kevin Begley [Saturday, Jan 19, 2013 19:15]; edited by Kevin Begley [13-01-19]

If you tried, even in the slightest, to avoid obtrusive force in your diagram, you must concede that obtrusive force is a flaw.

Consider the following problem:

Robert Lincoln
The Problemist, Jan 2012
(= 4+3 )

#2

At first glance, I am inclined to disfavor this problem, primarily because I consider the key to be flawed.
[note: for the purpose of discussion, I will ignore another flaw (of lesser significance) that I find in this problem.]
But, a good judge is obligated to look beyond that first impulse.

First, we should presume that the composer is well aware of this flaw.
[note: not only because we recognize this is a prolific composer -- we should always presume that the composer decided that this flaw is justified!]

So, what might justify this flaw?
I presume that the idea must be to show a Rook-Pawn Grimshaw, in orthodox miniature #2 form.

The first question that immediately comes to mind:
1) Is this flaw really justified?

A good judge must wrestle with whether this can be equivalently shown, without the flaw (or with a lesser infraction).
It would surprise me if this can not be shown without this flaw, but I haven't tried.

Suppose, after extensive effort, the judge concludes that this flaw can not be avoided, and significantly lesser infractions are nowhere to be found...

That brings the judge to the second question:
2) Even if the construction is optimal, is the thematic expression significant enough to warrant the flaw?

It's not my intent to answer these questions, for this particular problem.
Suffice it to say, while I do appreciate efforts to push the boundaries of miniature problems, I would be strongly inclined to question whether an arbitrary economy standard (7 men) should be deemed more paramount than a good key.

My point is just that this consideration process should apply to all flaws (regardless of severity).

And, if you agree, that we should strive to remove obtrusive force, whenever possible, from a diagram, then you are admitting this is a flaw.

A flaw (no matter how bad!!) does not render your problem worthless -- some flaws may be fully justified; and, beyond that, some problems with flaws are fully worthy of high praise!
A problem with flawed elements is not necessarily a flawed problem.

So, what's the debate?
Would you really employ obtrusive force in the diagram, which could be easily avoided?
Nobody would deliberately do this (without good reason) -- therefore, it must be, to some degree, a flaw.

However, an unsound problem (which is a far more important standard to settle!) is another story!
Why should we debate petty flaws, when we can't even yet agree on the fundamental question of soundness (e.g., promotion duals, duals in the final moves of selfmates, duals in general, etc etc etc)?
We can't even define the divisions by which we sub-divide the Album, or even the rules which govern some fairy elements.
And, if you want to talk about double-standards, explain why studies are worth more album points than problems (including fairy studies)!

How can we possibly agree on the standards which should apply to obtrusive force (except to agree that it should be removed, whenever possible)?
 
   
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(16) Posted by Hauke Reddmann [Saturday, Jan 19, 2013 20:26]; edited by Hauke Reddmann [13-01-20]

@Kevin: I may sound incoherent because I AM incoherent :P -
I insist on judging obtrusive force (or any other flaw) on a
diagram-to-diagram basis. This includes -@Ian- making a
difference between on-board and "Pronkin" [EDIT: must read "Frolkin",
I confused the retro themes] force.

Here, have some R-P-Grimshaw (of mine, SCHWALBE 13402)
(= 7+6 )

Also just an example - we could now discuss the pros and cons
of my setup (which are quite obvious, so let's omit that :-).
Likewise, we could discuss e.g. Qb4->Rb4, Ke8->e7,+Pc4 in the
retro-illegal problem.
My main point is that I prefer to judge obtrusive force only
on a compare-with-same-diagram-without base. And if I can't
construct such diagram, in a 2# of course, chances are good
that none exists. At this point I declare it as an irrelevant
flaw. Or I find one without, and it doesn't worsen the problem,
at this point I declare the componist a lazy geezer :-)
Anything in-between may happen.

Hauke
 
   
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(17) Posted by Ian Shanahan [Sunday, Jan 20, 2013 01:15]; edited by Ian Shanahan [13-01-20]

@Kevin. The old standard that obtrusive force is a flaw is not as uniformly upheld or as widespread as you think. As I noted, even in the 1930s, Loshinsky was awarded a 1st Prize despite an obtrusive Bishop. The ONLY standards that have remained constant and universal in regard to orthodox problems are:

1. That the position be legal - i.e. some proof-game from the game array to the position exists - and the correct side has the move;

2. That only the force present in the game-array is deployed in the diagram.

My reasoning is based SOLELY on these rock-solid standards. Neither "Pronkin" force (as Hauke calls it) nor obtrusive force necessarily violates either of these principles - i.e. the former does only if the officers aren't obtrusive but instead are supplementary promotees, while the latter (obtrusives) never do - whereas blatantly promoted force always transgresses the second principle (although I gave a context where it is perhaps justifiable).

In my previous post, I noted that "Pronkin" force might well be obtrusive and not promoted (i.e. supplementary to the game-array force), so I have not engaged a double standard myself!

Footnote: "If you tried, even in the slightest, to avoid obtrusive force in your diagram, you must concede that obtrusive force is a flaw."

Actually, for me this has only occurred once. I didn't regard the obtrusiveness as a flaw, but the editor I sent it to did. We worked together to eliminate it and because the construction was coincidentally improved - NOT because the obtrusiveness was eliminated! - I agreed to the reconstructed version. The moral of the tale is that trying to eliminate obtrusiveness is NOT an automatic admission that it's a flaw, but merely an acknowledgement that some of one's colleagues (including editors and judges) illogically see it as such.
 
   
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(18) Posted by Kostas Prentos [Sunday, Jan 20, 2013 09:39]

@Hauke What exactly do you mean by Pronkin pieces? The definition of the Pronkin theme is a promoted piece which returns to the initial square of the original piece of the same type (e.g. a promoted white Queen returns to d1). You probably mean Ceriani/Frolkin i.e. capture of a promoted piece.

In any case, my view on the matter of promoted force during the (theoretical) game that is used to prove the legality of an orthodox position is clear: There is no problem at all. The problem might be a heavy diagram which is the result of such promotions. It is up to the judge to decide whether the position of a problem is too heavy, or if such a heavy position is justified.

About the obtrusive force which appears in a diagram (not during the proof game), this is certainly a flaw. If it weren't, we would not bother trying to reach a position with the normal material. An obvious promoted piece (e.g. bBc6, bPb7, bPd7) is also a flaw, and should be avoided. The use of two Bishops moving on the same coloured squares (e.g. bBd7, bBc6) is a flaw. How bad? This is up to the judge and the people who look at the problem to decide. It depends on whether the content of the problem compensates for this flaw, or not. Like Ian, I have also published a problem with two light-squared Bishops (it even won an honourable mention, if I remember well), but I would gladly avoid them if I could. In my view, this flaw is of about the same importance as zero-position. I would use it, but only if a normal twin were impossible and the content so good that the flaw might be forgiven.
 
   
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(19) Posted by Georgy Evseev [Sunday, Jan 20, 2013 12:17]

There was an interesting discussion concerning this issue in Russian.

See http://ru-chess-art.livejournal.com/173813.html.
 
 
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(20) Posted by Kevin Begley [Sunday, Jan 20, 2013 12:55]; edited by Kevin Begley [13-01-20]

@Kostas,

Do you mean this one?

Andrei Frolkin
Kostas Prentos
3rd Commended, Thema Dancium, 2006
(= 15+12 )

PG16.5

The solution might also help to clarify the Pronkin, and anti-Pronkin Themes:

1.a4 g5 2.a5 g4 3.a6 g3 4.axb7 a5 5.fxg3 Ra6 6.Kf2 Rf6+ 7.Ke3 Rxf1 8.Qxf1 f6 9.Qf4 f5 10.Qa4 f4+ 11.Kd4 f3 12.Ra3 f2 13.Re3 f1=R 14.b3 Rf6 15.Bb2 Ra6 16.Ba1 Ra8 17.b×a8=B

The Bishop on a8 is obtrusive (an obvious promotion).
Whereas the standard for proofgames (which may contain elements of both forward and retrograde construction) certainly should be viewed holistically (read: not necessarily the same as directmates, and in accordance with the artistic achievement), the point remains -- generally speaking, any composer should prefer to avoid an obtrusive promotion.

If it had a path back to f1, or if it could be captured out of the diagram, it would certainly enhance the problem (read: solver's experience) -- even if there were clear retrograde evidence (whether by counting, or by pawn structure), the existence of this obtrusive unit, in the diagram, should be construed to be the means of lesser subtlety.

This is not nearly as bad as having a second bishop still sitting on f1 (but, even this flaw is not absolute -- many proofgames with promoted units have won high distinction).

I would expect that any composer/judge would prefer to remove the obtrusive force from this diagram.
However, this flaw (like all flaws!) should always be relaxed, if it best serves the intended artistic purpose.

The solver can easily deduce that the obtrusive bishop a8 must have promoted, thus the Bishop-phenix is a "diagram apparent" theme.
If that were all there were to this problem, it would likely not have been published (or I'd expect disfavor from the judge).
But, the judge here concluded (I suspect quite correctly) that this problem offers something more (which justifies this "flaw").
 
   
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MatPlus.Net Forum General obtrusive force: what say you?