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MatPlus.Net Forum General Most squares the Black king could be mated on in one, without being on the board?
 
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(1) Posted by James Malcom [Friday, Nov 6, 2020 05:55]

Most squares the Black king could be mated on in one, without being on the board?


I know I've seen this somewhere before on the forum, but I can't seem to find it again (and/or I'm to lazy to :]). The task stated that the Black king wasn't on the board, but no matter where they are, you could mate them in one. The goal was to maximize how many squares where it was possible. I vaguely recall a matrix with queening that allowed for a theoretical max of 32, but no one actually did it, as far as I remember.

It wasn't actually that hard to pull off, and even very economically as well.

#1 (-:
(= 8+6 )

1. gxf8=Q#

EDIT: wP5 has been removed.

Isn't this theme called Kriegspiel or the other?
 
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(2) Posted by Rosie Fay [Friday, Nov 6, 2020 09:09]

The construction task you describe in your message is different from the one in your title. Do you mean "Construct a position with bK missing, and find a White move, so that that move mates if bK is added on any of n squares, for n as great as possible"? Your title does not indicate that White has to play the same move in each of the n cases.
 
 
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(3) Posted by Hauke Reddmann [Friday, Nov 6, 2020 09:42]

(= 10+15 )


@Rewan: Has been done, my usual suspect is Karl Fabel. Couldn't find it on PDB or YACPDB though. Maybe WinChloe + matrix search?
@Rosie: Indeed, see matrix with 39 mates. (Now if someone could top that or
make a legal version thereof? :-) I bet this was done already either. Why, oh, why, don't we have an online construction task records wiki?)

Addendum: Legal but only 38. Next question: w/o promoted material.
(= 9+3 )

 
   
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(4) Posted by Juraj Lörinc [Friday, Nov 6, 2020 11:19]

Ah, juvenilia: http://www.jurajlorinc.com/chess/m2_5.htm#uloha2
 
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(5) Posted by Andrew Buchanan [Friday, Nov 6, 2020 11:22]

The text surely trumps the title. Rewan is talking about kriegspiel - i.e. there is just one mating move, and that must succeed wherever bK is located. I think he can remove wPb5, or am I missing something?
 
   
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(6) Posted by James Malcom [Friday, Nov 6, 2020 14:52]

Rosie, while the title may be unexact, please do read the actual text body, as Andrew points out. Juraj's #1 joke that he linked is exactly the kind of thing that I am looking for the same White move. White, on move, mates the Black king on whichever square they are allowed to stand, and without a choice of where it stands, with THE mating move.

However, on the second interpretation, I'll accept it, and Hauke's work, as an alternative construction task as well. It is similar, but instead White may choose where the Black king before commencing a mating move.

Andrew, you are right-white pawn edited out!
 
   
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(7) Posted by Jacques Rotenberg [Sunday, Nov 8, 2020 19:14]

https://matplus.net/start.php?px=1604858389&app=forum&act=posts&fid=xshowm&tid=595
see (11)
Jacques Rotenberg
after Michael McDowell
Matplus forum Sept. 10 2009
(= 8+6 )

1# Kriegspiel
1.gxf8Q#

I think I choose a queen on f8 so that you can say the key changes the color of the queen.
 
   
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(8) Posted by James Malcom [Sunday, Nov 8, 2020 21:03]

Ah yes, there is that thread! Thanks Jacques-the complete anticipation is a welcome expectation.

So, for Hauke, it seems that your thoughts on Fabel were indeed correct. Your task, of White placing the BK anywhere-not Kriegspiel, may I remind, is legally done by Fabel with a total, of 36 in the above linked thread. So congrats still on your illegal 39! Perhaps you may try legally with promoted pieces, as Fabel did without.

Karl Fabel, Fairy chess review 1939
(= 7+6 )

 
   
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(9) Posted by Hauke Reddmann [Sunday, Nov 8, 2020 22:41]

I already did, I edited the post after you read it :-)
 
 
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(10) Posted by Jacques Rotenberg [Sunday, Nov 8, 2020 22:43]

Perhaps another interesting related task : same request but in addition with as many mates as possible, two different stipulations :
a) each mate must be a different white move
b) as many different white mating moves as possible - with repeated white moves allowed -
a') and b') dual of promotion allowed/forbidden
 
   
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(11) Posted by Hauke Reddmann [Monday, Nov 9, 2020 11:09]

Just for comparison, the record of #2 variations (24) was done
by Petrovic (#91.624 Albrecht). Your suggestion is fascinating,
but a few attempts proved I better finish my thesis first :-)

EDIT: Even 16 are tricky if you do it systematically. For starters, 15:

(= 7+8 )

 
   
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(12) Posted by Jacques Rotenberg [Monday, Nov 9, 2020 18:20]

Well done Hauke,
a first (and naive) attempt without promotees :
(= 13+7 )

14 mates and a kind of AUW :
Kb7 : c8=Q#
Kf8 : c8=R(Q)#
Ka6 : c8=B(Q)#
Kd6 : c8=S#
= "special AUW"
Ka8 : Bd5#
Kc8 : b7#
Kh8 : g7#
Kh6 : Bxe3#
Ka4 : Rb4#
Kd4 : Rd5#
Kf4 : Rf5#
Kh4 : Rh5#
Kh3 : Qxh2#
Ka1 : Rc1#
 
   
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(13) Posted by Jacques Rotenberg [Monday, Nov 9, 2020 18:58]

Hauke, like that it looks slightly lighter :
(= 7+7 )

 
   
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(14) Posted by Hauke Reddmann [Monday, Nov 9, 2020 21:26]

Another suggestion:
How many mates can a single piece type give that way?
Simply can't get Ke3 no matter how I try... Q11 is to beat

(= 8+19 )

Qxb7/Qg8/Qd8/Qb5/Qf7/Qg5/Qa2/Qh5/Qa5/Qxd2/Qh1/Qg2
 
   
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(15) Posted by James Malcom [Monday, Nov 9, 2020 21:49]

Seems you could simply add +wBh1?
 
   
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(16) Posted by Hauke Reddmann [Monday, Nov 9, 2020 22:15]

Nope, doesn't work. Ruins Qh1#. Also, the problem with Ke3 is
Sg2#, and I can't protect g2 as Qg2# is needed. Maybe some
rotating helps.

Here is P6:
(= 6+16 )

exf8Q/exd8Q/d8S/e8Q/e8S/exf8S
 
 
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(17) Posted by Joost de Heer [Monday, Nov 9, 2020 22:18]

Dual in the Ka1 variant (Sc2)
 
   
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(18) Posted by Hauke Reddmann [Monday, Nov 9, 2020 22:51]

A Pc2 fell into a black hole :-)

S8 (showing white line combination is my second name :-)

(= 11+18 )

 
   
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(19) Posted by James Malcom [Monday, Nov 9, 2020 23:40]

For a rook, I also managed 8 as well, somewhat surprisingly for myself. I'm not so sure that 9 can be done.

(= 14+15 )

Rc2/Rxd2/Rb3/Rb4/Rb5/Rb6/Rb7/Rb8
 
   
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(20) Posted by Jacques Rotenberg [Tuesday, Nov 10, 2020 00:06]

what about f2, g2, a5, a7, and the others...
 
   
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MatPlus.Net Forum General Most squares the Black king could be mated on in one, without being on the board?