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MatPlus.Net Forum General A construction task
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(1) Posted by Hauke Reddmann [Saturday, Jul 23, 2011 16:28]

A construction task

Give an economic setting for a position with the
following property.

Black is losing. He is allowed to add any material of any color (no K)
and make any series moves (as long as this is legal by the usual
fairy conventions, e.g. as soon as he is checking White, White has the move)
in any order, but he is still lost.

Cheapskate try:

(= 2+21 )

I doubt you can do it in a legal position but surely you can improve my position.
(But not by dropping the Pd2 - think :-)

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(2) Posted by Siegfried Hornecker [Saturday, Jul 23, 2011 20:26]; edited by Siegfried Hornecker [11-07-23]

(= 32+32 )

You never said White needs a king. :-)

(= 5+7 )

And I hope you remember that in Rex Multiplex all kings or no king at all can be in check at once.

EDIT: Eh, the last one does not work, seeing now Black can add White material too. So add a queen on e3, gather all kings around it and capture all other White pieces and then the queen. Meh! Just add two more kings to that schema and it should work.

EDIT: Ok, here is a legal setting. Black has no way of winning any pawn by legal means. And looking at your first diagram he does not move with white pieces (or else 1.Bxg4 - 2.Bxf3 - 3.Bg4 - 4.Bh3 f3 5.Bxg2+ fxg2#). So since he can't legally add any Black pieces he has no way of avoiding the loss once White can move. And White CAN move at some point, or else your first diagram is also cooked. :P

(= 7+1 )

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(3) Posted by Nikola Predrag [Sunday, Jul 24, 2011 01:30]

Sigfried, perhaps I don't understand your rules. Black can add white Sf6,Bg8,Bh7,Ph6 and play Kg7-h8. Presuming that White may not play a series of moves, it looks as a draw.
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(4) Posted by Bojan Basic [Sunday, Jul 24, 2011 02:45]

Besides, as I understand Hauke, Black is not constrained by the requirement that the resulting position must be legal (therefore, in Siegfried’s example, Black also may add black pieces).
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(5) Posted by Hauke Reddmann [Sunday, Jul 24, 2011 17:22]

Yes. Black must keep the legality check-wise but NOT material-wise.
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(6) Posted by seetharaman kalyan [Monday, Jul 25, 2011 20:35]

Can we add fairy pieces? Black can mate white using fairy pieces.
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(7) Posted by Hauke Reddmann [Tuesday, Jul 26, 2011 13:15]

No fairy material or conditions.
(I hate problem composers, they are such wiseguys :-)
Yes, I see the usual snag: why allow one illegality
and forbid another?

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(8) Posted by Rewan Demontay (Real Name: James Malcom) [Saturday, Feb 1, 2020 00:36]

It’s probably just further cheating, but here’s a position that is four units lighter, ;-)

(= 2+17 )

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(9) Posted by Ulrich Voigt [Saturday, Feb 1, 2020 10:10]

How about this:

(= 7+4 )

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(10) Posted by Rewan Demontay (Real Name: James Malcom) [Saturday, Feb 1, 2020 15:55]

@Ulrich, that does not work. Do read the task rules.
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(11) Posted by Jakob Leck [Saturday, Feb 1, 2020 17:51]

Rewan, what should be wrong with Ulrich's idea? I think it is well within the rules. The black pawns could be left out, right? And the black queen as well?
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(12) Posted by Rewan Demontay (Real Name: James Malcom) [Saturday, Feb 1, 2020 18:12]; edited by Rewan Demontay (Real Name: James Malcom) [20-02-01]

Jakob, it is ENTIRELY wrong. The task is to make the most economic position where White has a mate in one, and Black can place any amount of Black and White pieces, minus kings, and can make any series of legal moves, but cannot stop the mate.
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(13) Posted by Joost de Heer [Saturday, Feb 1, 2020 18:46]; edited by Joost de Heer [20-02-01]

In this position, white has a mate in 1, because it's black's move. (see Codex, footnote 19). Without the queen, James would be correct in that it isn't a #1. The pawns can't be left out because of e.g. +bSf7, +bRg7.
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(14) Posted by Jakob Leck [Saturday, Feb 1, 2020 21:48]

"Black is losing" does not mean that there has to be a #1.
Thank you, Joost, I did not think of the cross-check idea. So the black pawns are necessary. And the queen as well, because if the game is over then black is not losing, he has lost.
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(15) Posted by Rewan Demontay (Real Name: James Malcom) [Saturday, Feb 1, 2020 22:23]

Ah I see that I misunderstood the task, Thanks Jakob.
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(16) Posted by Hauke Reddmann [Sunday, Feb 2, 2020 12:17]

Sounds legit. (I didn't specify whether Black is in check and even
whether the position itself is legal. Of course I *meant* the last
one, otherwise one could try e.g. illegal double checks. I also
intended Black not to be in check but so there. :-)
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MatPlus.Net Forum General A construction task