[blind-chess] Spoiler Alert Problem WAC037
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Sun, 3 Oct 2010 15:37:20 +0100
Hello all,
.
This posting is divided into various parts. You can jump to the headings of the
sections by search/find for **, a pair of asterisks
.
** Positional evaluation of the problem
.
White: Three pawn islands, the main feature is that d4 pawn. It is isolated,
but is protected no less than 4 times. The king is ready to advance in
anticipation of the endgame, however this is still a middle game, despite the
absence of queens. The rooks are not working to the best of their ability, the
c2 rook is unprotected on a file where black has doubled rooks, and therefore
should be of concern. The bishop is restricted by the d4 pawn, but should black
ever push e5, then it will come to life. The b5 knight has a fine outpost, it
can not be shifted by a pawn. The b3 knight is also offering protection to the
d4 pawn, but would be much better placed on f3, fighting for kingside dark
squares. White is employing over-protection to the d4 pawn, any of rook,
bishop, or either knight can freely move away whenever they want
.
Black: Three pawn islands, and despite having 2 backward pawns, b6 and e6, they
are safe from attack at the moment. The black king is ready to move to the
centre when the endgame arrives. The rooks, are working well, by being doubled
on the only open file. However, the c7 rook is attacked by the b5 knight, a
matter which must be resolved. The bishop is putting pressure on the d4 pawn,
and has an x-ray attack on the b2 pawn, should the centre open up. The a2
knight, placed on the edge of the board, which is usually regarded as not being
too good, is in fact working well, denying white the option to double rooks on
the c-file, which must occur at some point if white is going to put up a fight.
The c6 knight is putting pressure on the d4 pawn, and also supports a potential
e5 break, but is pinned to the attacked c7 rook
.
** Hints section, 5 hints
.
** Hint 1, to find the key move
.
Just because a piece is attacked does not mean it has to move
.
** Hint 2, to find the key move
.
Examine all forcing moves
.
** Hint 3, to find the key move
.
The power of the pin is to paralyse, but does it apply here?
.
** hint 4, to find the key move
.
Has white invested wisely in over-protection?
.
** 5th and final hint, to find the key move
.
There is an x-ray attack on the c2 rook
.
** Proposed solution to WAC037
.
Finding the first move may have occurred to you quite quickly, however the
analysis to confirm it is correct gets more complicated than usual.
It is a forcing move, a capture with check, 1. ... Nxd4+, and now white has 5
choices
.
Reply A: The first is to move the king, and there are 2 choices. Firstly to
advance with 2. Kd3, but quite remarkably 2. ... Nb4+ is mate. Note: This king
advance, and knight mate, can also occur in a number of lines that will follow.
So instead a retreats, to either e1 or f1, seem similar,
2. Ke1 Rxc2 3. Bxd4 Bxd4 4. Rxd4 Rxb2, and black is an exchange and pawn up
.
Reply B: The bishop capture, 2.Bxd4 Rxc2+, and black is an exchange and pawn
up. Perhaps 3. Ke3 Bxd4+ 4. Rxd4, and again the simple 4. ... rxb2 leaves white
with no play
.
reply C: The rook capture 2. Rxd4, trying to confuse matters. Black should not
fall for 2. ... Bxd4, because 3. Rxc7+ Rxc7
4. Nxc7 Bxe3 5. Kxe3 Kxc7 6. Nd4 Kd6 7. Nb5+ and white is getting some play, it
should be won after 7. ... Kd7, retreating instead of advancing so as to not
give the knight play with Nc7, attacking the e6 pawn at some point, and
heading into the kingside via e8, and the black pawns will be harassed. So
after 2. Rxd4, simply 2. ... Rxc2+ 3. Rd2 Rxd2+ 4. Kxd2 Kc6, black is an
exchange and pawn up
.
Reply D: The b3 knight capture, 2. N3xd4 Rxc2+ 3. Nxc2 Rxc2+ 4. Rd2 Rxd2+ 5.
Kxd2 Kc6, is simplest for the win, and if 6. Nd4+ Bxd4 7. Bxd4 g6, and black
will regroup the knight to c5, via either c1and b3, or b4 and a6, depending
where the white king moves
.
Reply E: The b5 knight capture, 2. N5xd4, will transpose into the variation for
move D above
.
** Condensed proposed solution
.
This line is selected as the main line simply because it is the one offering
black more chances to mess up a winning ending.
1. ... Nxd4+ 2. N3xd4 Rxc2+ 3. Nxc2 Rxc2+ 4. Rd2 Rxd2+
5. Kxd2 Kc6 6. Nd4+ Bxd4 7. Bxd4 g6
.
** Other tactical variations considered, and rejected
.
Not really a tactic, but 1. ... Rb7 would just give away the winning
opportunity. There are no other serious tactical tries, since the attacked rook
on c7 must be considered
.
** Alarm bells
.
1. Over-protecting a piece or pawn is often a good strategic idea, but other
factors in the position may make the protection an illusion
.
2. White did not pay attention to a forcing move, the potential capture with
check of the d4 pawn
.
3. Unprotected pieces, namely the c2 rook, should prompt one to seek ways to
exploit it's potentially precarious state
.
Paul Benson.
-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 29/09/2010 19:42
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC037
Good Morning Puzzlers,
This problem is from Mario Lang's puzzle web page at
http://delysid.org/chess/epd.cgi
and is reported to be from Fred Reinfield's book "Win At Chess" 1958.
Problem WAC037
Black to move
FEN Problem Setup:
2r5/
2rk2pp/
1pn1pb2/
pN1p4/
P2P4/
1N2B3/
nPR1KPPP/
3R4
b - - 0 1
Short Algebraic Problem Setup:
White: Ke2, Rc2, Rd1, Be3, Nb3, Nb5, Pa4, Pb2, Pd4, Pf2, Pg2, Ph2
Black: Kd7, Rc7, Rc8, Bf6, Na2, Nc6, Pa5, Pb6, Pd5, Pe6, Pg7, Ph7
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