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MatPlus.Net Forum General The Official Dummy Pawn Thread
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(21) Posted by Joost de Heer [Wednesday, May 27, 2020 20:58]


Maybe need to dig out an 1862 version of Stockfish (implemented on Charles Babbage's Analytical Engine) to check.

Or reprogram Stockfish's tablebase generator to allow pawn promotions.
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(22) Posted by James Malcom (Rewan Demontay) [Wednesday, May 27, 2020 22:31]

Here’s a fun fact that’s relevant: I’ve found that although that computer version Stockfish on Lichess won’t load analysis with pawns on the first and 8th ranks, the mobile app actually does for some reason. I intend to keep it like that by not telling the app developers since it helps me greatly.
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(23) Posted by James Malcom (Rewan Demontay) [Thursday, May 28, 2020 21:18]; edited by James Malcom (Rewan Demontay) [20-05-28]

Here is a different use the dummy pawn. Feel free to find a longer such sequence or a correct one if this is not so.

(= 13+0 )

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(24) Posted by Siegfried Hornecker [Friday, May 29, 2020 10:45]; edited by Siegfried Hornecker [20-05-29]

Seems to have many duals?
1.Kf5 2.Qb8 3.Qa8 4.Bc7 5.Bb8 6.c7 7.Rd6 8.Rd8 9.Be8 10.d6 11.Rh5 12.Rh8 13.Rf8 14.g8P 15.Ke6 16.Kd7 17.Kc8 18.d7

Moves can be made in nearly any order at the end.
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(25) Posted by Andrew Buchanan [Saturday, May 30, 2020 02:44]; edited by Andrew Buchanan [20-05-30]

Here's a new example of this steampunk theme, orthodox in 1862:

J.Malcom version A.Buchanan
motto: "The toast of Simpson's!"
(= 13+10 )
C+ Popeye v 0.4.7

I love the mottos from 19th century problems. They seem so cheesy and unnecessary, and underscore the difference in sensibility between their time and ours. And yet the language of chess problems themselves remains at base relatively unchanged since then. Dummy pawns are absurd and paradoxical, yet as the ultimate under-promotion they are very cool for composition. They are as fiddly and footling as en passant captures, but those came to occupy a special place at the heart of the retro genre. There's an extra thrill that comes for me as I imagine Howard Staunton incandescent with rage at the whole thing. And of course the dummy pawn theme offer so much virgin design space across all problem genres.

The motto here does not refer to Homer's breakfast. Simpson's-in-the-Strand was "the most important venue in Britain for chess in the 19th century" ('s-in-the-Strand). The "carvery" eat-as-much-as-you-want style is still a staple of British cuisine. The chess went away, but came back in 1980. I lived in London for several years, and it's ridiculous that I never visited. Mentioned twice in Sherlock Holmes (product placement?) it's now on my bucket list that one saner day I can lunch there - I hope with other problemists?
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(26) Posted by James Malcom (Rewan Demontay) [Saturday, May 30, 2020 03:43]; edited by James Malcom (Rewan Demontay) [20-05-30]

Andrew found a nice way to shorten P1376373-wonderful job!

Alas, it is cooked as note Siegfried. Here is a simple fix that avoids the king journey and should be correct.


(= 13+0 )

Sol: 1. Ka8 2. Qb8 3. d6 4. Rh5 5. Rh8 6. Rc8 7. Bd8 8. c7 9. Be8 10. d7 11. Rh6 12. Rh8 13. Rf8 14. g8=P=

Also, I have found a shorter version my two dummy s#4.

Dedicated To Henrik Juel
(= 10+5 )

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(27) Posted by Geir Sune Tallaksen Østmoe [Saturday, May 30, 2020 08:52]

There seems to be a different way:

1.Ka8 2.Qb8 3.Bd8 4.c7 5.Bd7 6.Bc8 7.Rd6 8.Rd7 9.d6 10.Rh5 11.Rh8 12.Re8 13.f8P 14.g8P=

There are move order duals on move 1, 2, 5, 6 and 13.
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(28) Posted by Peter Wong [Friday, Jun 5, 2020 16:09]

@Geir Sune, I have sent you a message through Notes here. Please check your Inbox!
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(29) Posted by James Malcom (Rewan Demontay) [Tuesday, Jun 16, 2020 18:08]; edited by James Malcom (Rewan Demontay) [20-06-16]

I've managed to create a PG that has another theme added in. Try to solve it!

PG 9.5, C+ By Jacobi
(= 12+13 )

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(30) Posted by James Malcom (Rewan Demontay) [Wednesday, Aug 26, 2020 20:40]

Here is the solution to the last proof game for those who didn’t solve it-1. a4 d5 2. a5 Qd6 3. a6 Qxh2 4. axb7 Qxg1 5. bxc8=P Qxf1+ 6. Kxf1 Kd7 7. Kg1 Kd6 8 Kh2 Nd7 9. Rf1 Rxc8 10. Kg1. The theme is false castling.

The other day, I found another concept that could be combined with the dummy pawn.

PG in 11.0 C+
(= 13+13 )

Dummy Pawn+Belfort Theme

This took Jacobi around 25-26 minutes to verifiy. Time well spent!
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(31) Posted by ichai [Friday, Aug 28, 2020 06:52]

what do mean “Belfort theme” ?
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(32) Posted by Hauke Reddmann [Friday, Aug 28, 2020 10:43]

I googled, it obviously is this:
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(33) Posted by Joost de Heer [Friday, Aug 28, 2020 17:18]

Belfort theme = This was a rapid composition tourney held during the FIDE Congress in Belfort, Jul. 1994. The tourney asked for dual-free SPGs where, in the final position, at least two units occupy initial squares of the corresponding opposite-color unit.

So no Belfort-theme as there is no second unit besides Bc8.
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(34) Posted by James Malcom (Rewan Demontay) [Friday, Aug 28, 2020 19:06]

Joost, I had asked Andrew if there was a theme for when a piece visits the home square of a similar colored piece, and he said Belfort. So what is the theme for a single visitation then?

EDIT: Removed an incorrect PG
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(35) Posted by Andrew Buchanan [Saturday, Aug 29, 2020 07:47]

Yes some slight confusion, sorry :D I naturally think of Belfort as a property of a single piece. Obviously implementing it just once is trivial, and the solver may think: why doesn't the composer extend it to Ceriani-Frolkin or Pronkin? So it's a "more the merrier" kind of thing. I'd forgotten the original tourney definition. The record I believe is P1000196 in PDB by Unto with an amazing 10 Belfort units!

A couple of other nuances on this theme, due to its visual nature:
(1) Any other non-Belfort unit 7th & 8th ranks (i.e. on the wrong squares) are very anti-thematic.
(2) A pawn on the 7th rank is thematic.
(3) A Belfort unit must achieve its status at the end diagram. It can't be on the key square and then go away.
(4) The combination of Belfort with another visual, end-diagram theme, Homebase, gives "Home and Away Base", and only a few examples are known. The legendary pure "Awaybase", where all surviving units are Belfort has never been achieved in a proof game, as far as I know. That would be a stupendous achievement
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(36) Posted by James Malcom (Rewan Demontay) [Wednesday, Oct 14, 2020 17:33]

For Joost de Heer and the lot of you all, a true Belfort.

PG 9.5, C+
(= 13+11 )

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(37) Posted by Andrew Buchanan [Sunday, Jan 9, 2022 13:41]

The idea that an individual piece on the diagram can have the Belfort property is still important. Numerous themes are more specialized than the underlying effect, but it's the *effect* that we want to reuse. We have to be able to move beyond the details of a particular tournament a long time ago.

Another example is Berlin. The granular effect is that a defence delivers mate. However the "Berlin Theme" is a specific implementation of this effect invented by the logical school.

A third recent example is Albino. The granular effect is basically a fountain of four White pawn moves, which may be achieved with a number of fairy conditions (recently Sentinels, Circe), as well as the traditional orthodox forms.

Many themes are already sufficiently granular, in which case no change is needed. But where simplification is helpful for re-use, rather than using confusing and discouraging prefixes like quasi- pseudo- etc, let's talk about them as effects.
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MatPlus.Net Forum General The Official Dummy Pawn Thread