﻿﻿ MatPlus.Net

Website founded by
Milan Velimirović
in 2006

2:41 UTC
 ISC 2021

Remember me

 CHESS SOLVINGTournamentsRating lists1-Apr-2021
 B P C F

MatPlus.Net Forum Helpmates h#2 with AUW

Page: [Previous] [Next] 1 2

### h#2 with AUW

(= 5+4 )

Olaf Jenkner
harmonie 105 (iii.2011)
h#2

1.Sxf8 exf8S 2.a1R h8Q mate

With the last move (gxf8B+) we have an AUW here. Is the task possible without retro or virtual play?

Witty idea!
A single solution AUW is most probably impossible in a helpmate in 2.

It was done in 2.5 moves for the first time:
Branko Koludrovic, Mat 1984
(= 10+13 )
h#2.5
1…bxc8=D 2.d1=L Dxe3 3.c1=T exd8=S#

and more economically:
Michael McDowell, The Problemist 1996
(= 4+5 )
h#2.5
1…gxf8=L 2.c1=T h8=S 3.Tc8 bxc8=D#

The first time this was done in 3 moves, according to my research:
Branko Koludrovic, Mat 1983, 1st comm.
(= 4+16 )
h#3
1.c1=L a8=T 2.Lg5 gxh8=D 3.f1=S Dxh1#

and more economically:
Martin Hoffmann, after Dirk Borst & Harald Haverkorn, Die Schwalbe 1992
(= 4+5 )
h#3
1.b1=T h8=S 2.Tb7 axb7 3.c1=L bxc8=D#

I think, it is impossible.
Some years ago I spent a lot of time to the theme "single-phase h#2 with 4 promotions". As result I wrote a small article (feenschach 04-06/2003, Nr. 151). Even using promoted force and white king in check the "best" result was the following terrible position with one (unique) cook:

Frank Richter
feenschach 151/2003, p. 64
(= 9+14 )

h#2
1.h:g1T h:g8S 2.b:c1L d:e8D#
1.K:h7 d:e8D+ 2.Dg7 Dg6#

Who is able to do this better?
At least I could compose two problems showing sDtS (P1074760) resp. tTsD (P1074761) promotions.

And P0521591 shows AUW in 2,5 moves too.

with a bQg8 you can take the bPh3 off the board

BQg8 will also remove the cook.

No, it remains the same.

Right :( Noticed after posting my comment. Could not remove it !

You were right to publish this even with the 2nd sol, the matrix and the construction are crafty

Thanks. It seems that in difference to the 100\$ theme it is impossible to find a correct realization even working with bK in chess and/or promoted pieces.
There are only very few matrixes allowing a "only promotion h#2".
The main difficulty is in my opinion to determine the black moves, especially their order.

Besides the question of whether achieving AUW is possible in h#2, w/o retro content, Olaf's fine problem begs 3 questions:
1) can additional retro-content be added, to achieve an AUW in fewer (forward) moves?,
2) can the retro-content be more precise (the last move is, after all, g7x?f8=B+)?, and
3) can anybody combine the AUW with an AUC (where AUC = all units captured/uncaptured)?

I'd most enjoy an answer to the last question.

Dear chessfriends,

because I got already some new positions for part 2 of the article, I'd like to ask not to publish here any results. Please send me your diagrams for publication in next harmonie issue, thanks!

(Just a first glance idea - I haven't studied where all the
problems will pop up in this construction, but I'm aware that

Hauke

You get the AUW-solution, but also with 1.Bg2, 1.Sg2 and 1.Sg6 ...

I already suspected such. (I could have checked with
Popeye first but h#, even 2 moves, are rather slow.
Yes, my PC is a Zuse :-)

Hauke

Frank, I did a random search on PDB today, and while browsing I came across this shocker: https://pdb.dieschwalbe.de/P0509017

Branko Koludrovic, Problem 1980
h#2
(= 7+9 )

1. c1=B hxg8=Q 2. g1=R exf8=N#

Apparently, it's cooked by 1. Kd7 according to PDB, but I suspect it was actually made with both solutions in mind. Someone would have to check the original source, if possible.

So it seems, Franks, under a two solutions pretense, your h#2 AUW idea was done 40 years ago without the garbled mess of promoted pieces! How unfortunate.

bPh3 pretty much shows that the author must have been aware of possible second solutions. Otherwise he wouldn't have prevented 1.g1N 2.Nh3.
But it is also obvious that - with the same moves by White - the 1.Kd7 and 2.Ke8 solution can't have been wanted.

This problem is well-known, and the second "solution" is clearly not acceptable in this context.

It is easy to do in hs#2.5 also!
Edit: seems difficult even in this stip..

You have crossed the line to the fairies!

Page: [Previous] [Next] 1 2

MatPlus.Net Forum Helpmates h#2 with AUW