[blind-chess] Spoiler Alert Problem WAC031
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Wed, 8 Sep 2010 19:14:41 +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 is a pawn up, but it is a doubled one, and has 3 pawn islands. The pawns
on the b-file and d-file are isolated which means, in the long-term they may
become targets. The white king is safe from any immediate threats, though the 3
unmoved pawns in front of him may leave the back rank vulnerable, should
tactics start flying around
.
The white queen is very active, and controls a number of squares in the black
position. She can also capture a rook on a8. The big question is, is that rook
a tasty snack, or will she get food-poisoning? The rook is well placed behind
the d5 pawn, and the knight has several options to improve. Every white piece
is better-placed than the corresponding black unit, this should lead one to
search for a decisive continuation
.
Black has a miserable position. While the kingside pawns are neat, they also
put the king in danger of a potential back-rack mating net. The a6 pawn sits on
an open file, always a potential target
.
The queen on f8 is rather inactive, at this stage of the game she should be
looking to put pressure on any weaknesses in the white position. The rook is
unmoved, has few prospects for improvement. It may or may not have a future,
depending on the appetite of the white queen. The bishop hems in the rook, but
is at least making a token effort for the black forces, by vaguely pointing
towards the white kingside
.
** Hints section, 5 hints
.
We are told there are two winning lines, one is considerably more instructive,
and that is the one I shall be hinting at
.
** Hint 1, to find the key move
.
Examine the sensible captures first
.
** Hint 2, to find the key move
.
Are x-rays beneficial to the black cause here?
.
** Hint 3, to find the key move
.
however discouraging a line may appear, analytical persistence in the face of
adversity is necessary here
.
** hint 4, to find the key move
.
The first 2 moves may lead one to abandon the winning line, it is the 3rd white
move that clinches the deal
.
** 5th and final hint, to find the key move
.
Sometimes the most powerful can be humbled, and forced into submission by
coordinated teamwork from the less powerful
.
** Proposed solution to WAC031
.
Time to analyse tactics,and it is all about the black rook. The black queen is
giving x-ray protection to it. So what? that is not stopping me. So, 1. Qxa8,
and the onus is on black now. If there were no black bishop then the white
queen is lost. So, black plays 1. ... Bxh2+, a capturing check which reveals
the black queen's x-ray forces, aimed at whatever sits on the a8 square. Now
white is losing the queen. After 2. Nxh2 which is the better capture here, if
the king were to capture it might be exposed to a check at a vital point later.
Black has 2. ... ... Qxa8, and there is material imbalance. Now white
demonstrates how teamwork wins with 3 d6, the move which had to be found when
considering taking the a8 rook. This passed pawn is going all the way. If 3.
... Kf8 4. d7, and the king can not blockade the pawn, that must be done by the
queen. So 4. ... Qd8, and now it is time to think again
.
If the queen ever moves, the pawn will be promoted immediately, and after all
exchanges on d8 white will be a piece up. White just keeps the rook on d1, and
move the knight around until it lands on either c6 or b7, which attacks the
queen. If black could have got the king to d8, then the queen would be free to
roam the board, and easily prevent the knight journey
.
A sample line: 5. Nf3 f6 6. Ne1 e5 7. Nc2 a5,note how the knight can not step
onto the d-file, and now black is trying to stop it getting to c6 via the b4
square. Now 8. b4, and if black captures, the knight will get to c6 in 2 moves.
If black pushes past, then white pushes the b4 pawn to b7, transfer the knight
to c6, and one pawn costs black a queen, the other pawn will become a queen.
.
** Waffle-free proposed solution WAC031
.
1. Qxa8 Bxh2+, 2. Nxh2 Qxa8, 3. d6 Kf8, 4. d7 Qd8, 5. Nf3 f6, 6. Ne1 e5, 7. Nc2
a5, 8. b4 and the white knight has a clear path to c6 winning
.
** Other tactical variations considered, and rejected
.
A less dramatic way to achieve a decisive advantage is 1. dxe6 fxe6 2. Ra1,
doubly attacking that a6 pawn. If now 2. ... Ra7, then 3 Qc6, and black has the
a6 and e6 pawns attacked.
If then black tries 3. ... Qf7, to protect the e6 pawn and stop any white Qe8+
ideas, then 4. Qc8+ Qf8 5. Qxe6+ Qf7 6. Rxa6 Rxa6 7. Qxa6 Qxb3 8. Qe2, and
white has 2 extra pawns. White slowly regroups to push the black queen back,
starting with g3 and kg2, and then the knight can start moving around. This is
a long game in prospect
.
** Alarm bells
.
1. Black thought the rook was protected by an x-ray defence, which it was, but
other factors were more important.
2. A paradox. The white queen was so well placed, and the black rook and bishop
were contributing little. Yet, the correct route to victory was to give up the
strong queen for rook and bishop.
3. This is only so, because white could have a well-advanced passed pawn,
supported by a rook, and most importantly, the defending king could not
blockade the passed pawn
.
Paul Benson.
-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 07/09/2010 16:04
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC031
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.
Apparently, in this problem White has the happy choice of more than one
solution.
Problem WAC031
White to move
FEN Problem Setup:
rb3qk1/
pQ3ppp/
4p3/
3P4/
8/
1P3N2/
1P3PPP/
3R2K1
w - - 0 1
Short Algebraic Problem Setup:
White: Kg1, Qb7, Rd1, Nf3, Pb2, Pb3, Pd5, Pf2, Pg2, Ph2
Black: Kg8, Qf8, Ra8, Bb8, Pa7, Pe6, Pf7, Pg7, Ph7
Other related posts:
