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problem 4040 misses an alternate solution

 
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Jazz Writer
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Joined: 25 Nov 2008
Posts: 3

PostPosted: Tue Nov 25, 2008 3:26 pm    Post subject: problem 4040 misses an alternate solution Reply with quote

problem 4040 overlooks another solution. After white sacrifices his bishop, queen and newly queened pawn to black's bishop:

1. a8-g2 h1:g2
2. d1-h1 g2:h1
3. a7 h1-f3
4. a8 (Q) f3:a8

the following moves will avoid the stalemate:

5. c1-e1 / a8-c6
6. a2-b4

Regardless of where the black bishop moves, one of the two white rooks will succeed in obtaining a back rank mate, as the bishop must move and can no longer guard both a8 and e8 from the rooks. Also, there is no way for the bishop to check the king immediately, nor for the black king to free itself.

For example if 6.... c6-e4, 7 e1-e7 and the bishop can't successfully hold both 8th rank squares.

I'd love to get a pm if someone has spotted a flaw in my reasoning. I haven't been playing much lately but have found some of these chess problems to be of interest.

Hopefully, my notation is correct. I still use the old-fashioned English descriptive, which is harder to keep up with but gives me a better idea of what's happening in a game at a glance.
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888
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Joined: 17 Dec 2007
Posts: 35
Location: China

PostPosted: Tue Nov 25, 2008 11:14 pm    Post subject: Reply with quote

Well, black does not need to go Bc6 to e4, there is a better defence for black: 1...Ba4!!
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888
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Joined: 17 Dec 2007
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Location: China

PostPosted: Tue Nov 25, 2008 11:21 pm    Post subject: Reply with quote

Sorry, after further investigation, I will say your are right, after 1...Ba4!, white can pushes d pawn to force bishop go to d7.
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papadoble
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Joined: 15 Jan 2006
Posts: 85
Location: Yerres, France

PostPosted: Wed Nov 26, 2008 5:07 am    Post subject: Reply with quote

5.Re1? Be4!, similarly 5.Rf1? Bf3!
This composition is very interesting and not so easy to solve, e.g. 2.a7? is tempting but leads to nothing after 2...~ 3.a8=Q+ Bxa8 4.Qh1 Bxh1 because the c1 square is not cleared.
You may also comment on problems directly on the relevant problem pages, we are a few to track comments on http://www.chessproblems.com/rss/comments.php
Btw welcome Smile
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Jazz Writer
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Joined: 25 Nov 2008
Posts: 3

PostPosted: Sat Nov 29, 2008 11:10 am    Post subject: Reply with quote

The problem resulted from the flawed Black move 5... Bc6
that automatically followed in response to my 5. Re1.

I agree that 5... Be4 forces the stalemate, as does 5 Rf1 Bf3.

There must be a bug in the program, as my move still wins after 5...Bc6? There is no stopping a back rank mate.
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888
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PostPosted: Sat Nov 29, 2008 6:42 pm    Post subject: Reply with quote

But can't white goes 6.Ra8+! to win? Because the a7 pawn is not longer on the board.
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papadoble
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Joined: 15 Jan 2006
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Location: Yerres, France

PostPosted: Sun Nov 30, 2008 1:38 am    Post subject: Reply with quote

There is no bug in the program because there is no program for endgame studies (only for #1/2/3).
The wrong reply 5...Bc6? to 5.Re1? had been entered by puzzle setter.
The solution is now edited.
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