﻿﻿ MatPlus.Net

Website founded by
Milan Velimirović
in 2006

14:08 UTC
 ISC 2020

Remember me

 CHESS SOLVINGTournamentsRating lists1-Jan-2020
 B P C F

MatPlus.Net Forum General The Black Home Task

Page: [Previous] [Next] 1 2

Hehe. I love puns! A box of chocolates for everyone who can figure it out!

Anyhoo, I had an “idea,” after reseeing an old problem, to force as many Black pieces as possible back home in a selfmate.

Did I achieve four?

Yes, the key is bad, but you gotta live the checks, as otherwise this would be nearly impossible to achieve.

s#5, Cooked?

(= 12+8 )

Solution:

1. bxc8=N+ Bxc8

Killing the guard of the 8th rank, Black’s light-squared bishop covers e6

2. g8=N+ Nxg8

Opening a line for the Black dark-squared bishop

3. f8=Q/B+ Bxf8

The Black dark-squared bishop guards d6

4. Qc5+ Ke8

Preparing the final check

5. Ba4+ Rb5#

Forced checkmate+selfpin

Do you know the 2005 Costeff humor study? White Home, but still.

There is a (quite famous, I think) selfmate with home returns of all eight white officers by Mark Kirtley, PDB P1081510.

Yes, I know of both-Krabbe #288. A box of chocolate for you both!

The final, corrected version of my problem can be seen here: http://superproblem.ru/archive/probl/Sn/Malcom-s5-2019.gif

Now the return of 5 Black pieces has been achieved: http://superproblem.ru/archive/probl/Sn/Malcom-s5-2019-2.gif

Well done!

Thanks seetharaman!

This record was just broken by Grigory Popov - http://superproblem.ru/archive/probl/Sn/Popov-s7-2019-2.gif

This s#7 is an impressive construction, but we should note, that in final position the bQ has left again the original square.
Kirtley's white homebase task (that was taken as inspiration) shows all 8 white pieces in homebase position at the end.

This is of course more difficult, but should be the ultimate target for the black homebase task too.

In my opinion S#7 by Popov is incorrect problem. The 5th white move is not unique (5.b8Q/R+). This is the major dual if it's not on the lat move and I do not think it can be accepted. This cannot be counted as a task.

Adding on to Frank’s words, Popov put his s#7 as a seprate record of 6 pieces going back during the game, while my s#5 is the record for the game ending with the pieces in place.

Popov's stipulation should be: s#1 in 6 moves

Miiodrag, in reagrds to your opinion, then you would also think that my s#5 is incorrect.

See Article 13 of the codex:

https://www.wfcc.ch/1999-2012/codex/

I wonder why dualized problems should not be unsound. In my opinion a promotion dual can be tolerated if the promoted piece is immediately captured. The composer should avoid such promotions, but such problems are never cooked.

13.2 needs major rewording, since the current wording renders compositions with multiple solutions branching after the first move (e.g. 2.2.1.1) as unsound.

Just to confirm. I do think that S#5 is incorrect too. I think that promotion dual can be only accepted on the last move. Although per codex it looks like this dual is only accepted in helpmates on the last move. This would mean that even if there is a dual on the last white move the problem is incorrect.

QUOTE

Yes, I know (although the footnote refers to other types of composition, e.g. direcctmates).

Article 10 – Dual
A dual is said to occur if, after the first move, there is more than one method of satisfying the stipulation.

Article 13 – Unsound Chess Compositions
(2) Help-play compositions are unsound also if they are dualized, except that in the final move a promotion into different pieces having partially the same power (for example queen/rook or queen/bishop) may be tolerated [16]

According to article 10, a helpmate with stipulation 2.2.1.1 is dualistic, since after the 1st move there are 2 methods (i.e. more than one) of satisfying the stipulation.
Accorting to 13.2, dualistic helpmates are unsound (unles[..], which is not relevant here), so a helpmate with 4 solutions, divided as 2.2.1.1 is unsound.

@Miodrag: Duals aren't mentioned in article 13 (which deals about unsoundness) for direct play, so dualistic directmates aren't unsound.

... for direct play, so dualistic directmates aren't unsound.

Hard to believe, but written in the codex.