[blind-chess] Spoiler Alert: Problem WAC095
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Mon, 3 Sep 2012 22:03:44 +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: Two pawn islands, and an exchange down. The c3 pawn is isolated and is
going to be difficult to defend. The e5 pawn is supporting the f6 knight. The
doubled f-pawns are at present not easy targets, but they will become exposed
as any endgame proceeds. The king on g2 has little pawn cover, and is in check
from the black queen, this must be immediately addressed. The queen on e3 is
protecting the e5 pawn, is attacking the checking black queen, and is also
pinning the black queen to the black king. The a1 rook is ready to invade down
the a-file, but might find defensive duties are going to be needed soon. The f6
knight has a splendid outpost, it controls several squares in the kingside, and
can not be removed from the outpost by a black pawn. Without a doubt, the best
placed of the white forces, though it might be worth pointing out that the
knight at present has no safe move
.
Black: Two pawn islands, and an exchange up. This extra exchange will soon
prove very difficult for white to neutralise. The h5 pawn is passed, and will
increase in strength as further material disappears from the board. The central
e6 and d5 pawns are effectively blocked, but this is not permanent, as the
white c3 pawn is weak, and likely not to remain in the game for long. The king
on h6 has some pawn cover, is protecting the black queen, whose presence is
intended to neutralise any white kingside activity. The queen on g5 is giving
check, can be potentially removed from the board if white chooses to trade
queens, and is pinned to the black king. The b7 rook is located on a fully open
file, and is ready to invade up the board, possibly pressuring the weak white
c3 pawn. The c8 rook is attacking the weak white c3 pawn, and should that pawn
fall, the d5 pawn will become the second protected passed pawn for black
.
** Hints section, 5 hints
.
Hint 1, to find the key move
.
White reverses the Richard III offer regarding a kingdom
.
Hint 2, to find the key move
.
Sometimes, going backwards is progress
.
Hint 3, to find the key move
.
Is it possible to force lines open by passivity?
.
Hint 4, to find the key move
.
Should a line open up, who could be pushed around?
.
Final hint, to find the key move
.
Surprisingly, someone is going to lose a queen
.
** Proposed solution to WAC095
.
A curious position. It might be worthwhile investigating just what the previous
2 moves were. Since it is white to move, and the white queen is on the same
diagonal as the black king, though the black queen is in between. So, black's
last move must have been to move to g5, which blocked a check from the white
queen, which also gave check to the white king. It might have been that the
white queen was sitting on e2, and the black queen on f5. White played, Qe3+,
and black blocked with, Qg5+. So, curiosity satisfied, now for the proposed
solution
.
White is an exchange down with no obvious positional compensation, any endgame
will be slow torture, the black rooks are soon to demonstrate their powers to
the full. However, what is potentially in the short distant future, is not
automatically destined to occur. The black king might seem to be safe,
appearances can be deceptive, once tactics start to flow. White takes a leaf
out of black's book, and blocks a check with a check, and plays, 1. Ng4+. Black
has little choice here, and must play, 1. ... hxg4, which opens up the h-file.
Note, if instead, 1. ... Kg7, the only defence to the black queen has been
removed, and white can play, 2. Qxg5, winning. So after, 1. ... hxg4, white
reveals the point of giving up the knight with, 2. Rh1+. The h-file has become
opened up by the retreating knight sacrifice, permitting the a1 rook to
suddenly invade on an area of the board where no action was previously
expected. Black can not block this check, the queen on g5 is pinned to the
black king by the white queen. So, the black king must retreat with, 2. ...
Kg7. White has undermined the defence of the black queen by pushing the black
king away, and now gains a decisive material advantage by playing, 3. Qxg5.
Black could choose to play a few more moves, hoping only for massive blunders.
Perhaps, 3. ... gxf3+, but since white has complete control of the kingside,
white should avoid complications of capturing this pawn, and calmly advance the
king with, 4. Kg3. Black is now threatened with, Qf6+, followed by, Rh8+ mate.
For those wishing to sharpen their finishing skills, here is how quickly the
game could be concluded. There are 3 defensive tries for black
.
Firstly, 4. ... Rf7, allows white to invade on the dark squares and force mate
in 2 moves with, 5. Qh6+ Kg8 6. Qh8+ mate
.
Secondly, black tries, 4. ... Rf8. There are several ways for white to win
here. The simple, 5. Rh6, creates unstoppable threats to the black king, once
the g6 pawn is captured. There is also the apparently materialistic, 5. Qh6+
Kg8 6. Qh8+ Kf7 7. Qh7+ Ke8 8. Qxb7, white has won a rook, and is now a whole
queen ahead, and mating ideas are still present, simply transferring the h1
rook back to a1 seems crushing, though there are other equally good ways for
white to deliver mate
.
Thirdly, black tries, 4. ... Kf7, leaving white a variety of ways to win. The
simplest is to invade on the 7th rank with, 5. Rh7+, forcing the black king to
the back rank. Now, there is nothing wrong with simply winning a rook with, 6.
Rxb7, as mate will surely follow. Instead of snatching the rook, white can
actually play for a forced mate against any of the 3 king retreats to the back
rank, beginning with a queen check against any of black's moves. The key to the
mating attack is for white to to be able to play, Qf6, with check, which then
allows the queen to move to the h8 square with mate. For example, if 5. ... Kf8
6. Qf6+ Kg8 7. Qh8+ mate. Instead, after 5. Rh7+, the black king can avoid the
immediate dark square invasion by retreating to a light square with either, 5.
... Kg8, or, Ke8, it actually does not matter which. Now white must manoeuvre
for that dark square queen check, starting with, 6. Qxg6+, and assuming black
does not interpose a rook, then the black king must move to a dark square,
which allows white to play, 7. Qf6+, leading to a mate again on the h8 square
.
** Condensed proposed solution
.
1. Ng4+ hxg4 2. Rh1+ Kg7 3. Qxg5
.
** Other tactical variations considered, and rejected
.
Anything which involves a queen trade is rather dismal. White will have no
compensation for the exchange deficit. White would be desperately trying to
salvage a draw
.
Option 1: White plays, 1. Qxg5+ Kxg5, and now white has to protect the c3 pawn
with, 2. Ra3. Note, if instead white tries for counterplay with, 2. Ra6,
attacking the black e6 pawn, black has, 2. ... Kf5, which not only protects the
e6 pawn, but also attacks the white e5 pawn. So after, 2. Ra3, black has
either, 2. ... Kf5, attacking and winning the e5 pawn, or, 2. ... Rbc7,
doubling the attack on the c3 pawn, which is now lost. Black is quickly picking
up at least 1 pawn, soon to become 2 pawns gain. Note, if white loses the e5
pawn, the f6 knight will be without support, and appears to have no safe escape
squares on the kingside, black is easily winning
.
Option 2: White plays, 1. Kf1, to escape the check, but this permits black to
trade queens with, 1. ... Qxe3. After, 2. fxe3, black wins a pawn with, 2. ...
Rxc3. White has no sensible means of creating complications, black only has to
play carefully to win
.
** Alarm bells
.
1. The position arose by black choosing to block a white check with a counter
check. This is uncommon. White was aware of the opportunity to play similarly,
and find a winning tactic
.
2. It is said, that finding retreating piece moves for pieces which have no
reason to retreat, is one of the most difficult of tactical opportunities to
find. Be aware, that well-placed pieces can retreat for bigger gains
.
3. White resisted the temptation to make the simple move, that of trading
queens. Instead, inspiration combined with some tactical calculation,
discovered a move which apparently loses a piece. Just because a piece can be
immediately lost, should not rule it out of consideration
.
4. The white rook on a1 surely had no ambitions of kingside activity. It is
easy to think a piece has duties to perform on one side of the board only. With
the forcing knight sacrifice, the opening of the h-file, permitted the rook to
be transferred the complete width of the board, and contribute to a surprising
attack with with devastating effect
.
5. The king is a vulnerable defender, any check, which is essentially an
attack, it receives must be resolved immediately. Other pieces have the option
to ignore an attack, and instead counter activity can be sought elsewhere on
the board. The lack of mobility for the black king led to the defender being
forced to leave the black queen defenceless
.
Paul Benson.
-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 29/08/2012 19:15
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC095
Good Morning Puzzlers,
Another WAC series problem.
This problem is from Mario Lang's puzzle web page at:
http://delysid.org/chess/epd.cgi
Problem WAC095
White to move
FEN Problem Setup:
2r5/
1r6/
4pNpk/
3pP1qp/
8/
2P1QP2/
5PK1/
R7
w - - 0 1
Short Algebraic Problem Setup:
White: Kg2, Qe3, Ra1, Nf6, Pc3, Pe5, Pf2, Pf3
Black: Kh6, Qg5, Rb7, Rc8, Pd5, Pe6, Pg6, Ph5
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10:33:00
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