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MatPlus.Net Forum General The \$80 Theme

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### The \$80 Theme

Here's a little fun for you all.

h#4, "The \$80 Theme"
(= 6+9 )

This should be self explanatory. Of course it has a small resemblance to Jeno Ban's h#5.

Now, the challenge: Who can do it more economically with no promoted force and/or find a predecessor?

Better yet, feel free to retract a move, with promoted force allowed then. :D

Well, one obvious way to save three pieces is to move position one line left:
(= 5+7 )

It only actually saves one piece, as the other Black pawn is there for thematic reasons, which necessitates a BP on c4.

(= 5+9 )

The more popular way to make the 100 dollars easier to achieve is, of course, use of promoted material, the idea of an "80 dollar" version of the theme (would the prize really be proportional to the number of moves? ;) ) was unknown to me so far, but a quick search in the pdb showed that you were not the first to think of it. I used the search command
STIP='h#4' AND SOL='4. _1=S%=S#'
and found https://pdb.dieschwalbe.de/P0502375 (more than 50 years old!) and two problems using a board with only seven rows: https://pdb.dieschwalbe.de/P1287420, https://pdb.dieschwalbe.de/P1270997.

@ Rewan
My position in post (2) is correct and it does not have cook (position with three saved pieces). Can you please give us definition of \$80 theme? I do not see any difference in solution (in original and my position there are two promotions to black knights). Not sure why are you assuming the everyone is familiar with \$80 theme?

Thanks for finding a predecessor Jakob! P0502375 fits the bill perfectly, and it is much more econmic as well.

@Miodrag While your postion is correct in terms of the solution, I meant that it is not thematically correct. Sorry for the confusion; I cleaned up my post a little.

The concept of “The \$80 Theme” was somewhat of joke. It’s just the \$100 minus the double step for the respective pawns. By my definiton, the themetic pawns must have been able to make a double-step on the game turn before the presented diagram. I call it “\$80,” as 100/5=20-in other words \$20 a move. :-)

(= 3+3 )

(Admin, can we have an option for nonstandard boards? This shall be 8*3)
1.cxd1S b3S#. Rewan, you owe me 20€ :-)

Why not 21x3? So it's almost a real chessboard with 63 squares.

(= 3+3 )

(= 3+3 )

I knew from many years ago there was a code for custom board sizes and shapes. But as the help never was completely written, how exactly did it go?
Also, what was the spoiler code?
Maybe someone can write the complete help file?

Nonstandard board sizes: http://matplus.net/start.php?px=1578997693&app=forum&act=posts&fid=gen&tid=3

@Rewan - Problem isn't cool enough yet :-)
(And THX @Joost for reminding me)

(= 3+2 )

B promotes to Bishop
(= 3+2 )

B promotes to Rook

Anybody able to do all three underpromos with twinning?

If you add another half move, you can call and \$ 90 theme)). Here we already get a checkmate in five moves.
4bnq1/4nk2/6p1/3pp3/p1pP1p2/P1P2P2/2KPP3/B7
1...e4 2.exd4 exd5 3.dxc3 d6 4.cxd2 d7 5.d1=S d8=S#

Nice idea Kenan! :-)

But in my opinion, the themeatic Black should have been able to do a double-step on the game turn before the diagram to be fully themeatic. But that’s just my skittles!

Dear Rewan, back in 2010, at the suggestion of Rauf Aliovsatzadeh, I started working on this theme. Then I got it with two turned bishops. Then numerous analyzes showed that in a complete set it will not be possible to fulfill the theme. Compared with the rest of the tasks compiled, we see here in the 5th move two promotions on a S.The conditions of the theme require it, in 5 moves per S. As well as reciprocal excelsior. According to the rules of the genre 4.5 there are 5 moves))

P1111722
Kenan Velikhanov
608 The Ural's Problemist 61 2010

(= 8+13 )

h#5
1) 1. a5 a4 2. axb4 a5 3. bxc3 axb6 4. cxd2 bxc7 5. d1=S cxd8=S#
2) 1. e6 a4 2. Lf6 a5 3. Lxc3 axb6 4. Lf6 bxc7 5. Ld8 cxd8=S#

Kenan, just to be clear, are you saying you have proved the 100\$-task to be impossible? And if so, how did you do it? By going through all potential combinations of white and black excelsiors?

If you read carefully above, then I'm pointing to \$ 90, I also meant% 90.There is a mutual excelior in the problem, but not from the initial position. Ultimately, the consecutive movement of pawns and promotion into horses indicates the completion of the theme.I’ll work a little more, and I’ll give black turn

Thank you dear Frank! I somehow did not save this task. I was just looking for her))