[blind-chess] Spoiler Alert: BWTC427
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Sun, 22 Jul 2012 20:23:23 +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 a pawn down. The symmetric nature of the queenside
pawns, 3 white against 3 black pawns, means neither side can forcibly create a
passed pawn. The white pawn on c4 is unprotected, but not likely to come under
pressure for some moves. The h5 pawn is also unprotected, and could be a target
as it is blockaded and on light squares, though black would be ill advised to
go after this pawn without trading heavy pieces off first. The h5 pawn is
always going to be a weakness in the long term. The king on b2 is not in any
immediate danger, though the open nature of the position, combined with the
presence of queen and rook each, means white will always need to keep pieces
nearby. The queen on d2 is undefended and also attacked by the black queen, but
has good activity down the fully open d-file. The rook on e5 is posted on a
fully open e-file, and is also undefended. The c2 bishop is offering some
defence to the king. Despite it's apparent inactive location, it is controlling
important light squares on the b1-h7 diagonal, and can not be easily challenged
for control of those squares
.
Black: Two pawn islands, and a pawn up. The 3 queenside pawns have no
weaknesses, and being on dark squares, can not be attacked by the white light
square bishop. Similarly, the 2 kingside pawns on dark squares are safe from a
bishop attack, though the fact they have advanced to h6 and g5, means the h6
pawn could become a target for future pressure from white heavy pieces. The
king on f8 has only a rook offering defence. The b1-h7 diagonal is totally
under white's control, and limits the movement of the black king, should white
invade. The queen on f2 is actively placed and threatening to trade queens, a
favourable trade for black, since being a safe pawn up, all piece exchanges
will be desirable. The f7 rook is trying hard to offer defensive protection for
the king, but in doing so, it could also be regarded as restricting the
movement of the black king. The bishop on b7 is pointing into the white
kingside, but can not gain anything from it's present location. At some point,
black should consider challenging the white bishop on c2, to remove it's
potential threats in the black kingside
.
** Hints section, 5 hints
.
Hint 1, to find the key move
.
The black king needs restricting in a straight-jacket
.
Hint 2, to find the key move
.
In boxing terms, white's one-two sequence, is a push followed by a punch
.
Hint 3, to find the key move
.
The black king is not being given any choice in this mating attack, each reply
move is forced
.
Hint 4, to find the key move
.
This is a dark square destruction
.
Final hint, to find the key move
.
The black king starts on the edge, and is pushed over to another edge
.
** Proposed solution to BWTC427
.
White has a forcing sequence of moves, and as it happens, black will only have
one legal reply to each white move. These types of combinations are the easiest
to calculate, since there are no branch points in the analysis
.
The first move is relatively easy to find, since it follows natural attacking
principles. White plays, 1. Qd8+. This natural invasion has taken control of
the entire 8th rank, an important factor in the process of surrounding the
black king. Black must play the forced reply, 1. ... Kg7. Now all the
unoccupied squares around the black king are attacked by white units. Now white
must find a strong move, since any non-critical move will allow black to defend
with, 2. ... Qf6, relieving much of the white pressure. The only white piece
not yet contributing to the attack, makes a powerful blow with, 2. Rxg5+, and
again all the potential flight squares for the black king are covered by white.
So, black replies, 2. ... hxg5. What has white gained from the rook sacrifice?
The black pawn which was previously on h6, is now on g5, a deflection, leaving
the h6 square unoccupied. Ah, but the absence of a black h6 pawn, also means
the previously blockaded white h5 pawn, now has mobility. White keeps up the
assault with, 3. h6+, and yet again black has only one reply. Black plays, 3.
... Kxh6. So, what has white gained for the donated rook and pawn? The black
king is now on the edge of the board, which means only 5 potential flight
squares, one of which is occupied by the g5 pawn. This means white now only has
to cover 4 unoccupied squares to snare the black king in a mating net. White
continues with, 4. Qh8+, which takes complete control of the h-file, denying
the black king escape down that route. The controlling influence of the white
bishop on c2 is now fully appreciated, as the g6 and h7 squares are guarded.
Black has to play, 4. ... Rh7, to block the check, but the rook has landed on a
square which is twice attacked by white. The game ends with, 5. Qxh7+ mate, a
dark square destructive attack ends with a light square mate
.
** Condensed proposed solution
.
1. Qd8+ Kg7 2. Rxg5+ hxg5 3. h6+ Kxh6 4. Qh8+ Rh7
5. Qxh7+ mate
.
** Other tactical variations considered, and rejected
.
Since white is a pawn down, entering the endgame with heavy piece exchanges is
undesirable. So, 1. Qxf2 Rxf2, only assists black, and should be avoided, the
pawn structure in the black position has no obvious weaknesses to exploit, and
the white h5 pawn is beginning to appear very weak
.
Instead, white could attempt a dark square invasion, down the a1-h8 diagonal
with, 1. Qc3. The plan is to follow up with a rook move such as, either 2. Re6,
or, 2. Re3, which creates a threat of, 3. Qh8+ mate. This is a good try, but is
far too slow. Black can challenge this immediately with, 1. ... Qf6. This pins
the white rook to the white queen, and since the white king is also on the
a1-h8 diagonal, white will find it almost impossible to prevent some heavy
piece exchanges
.
Another try for white is, 1. Re2, which prevents a queen trade, and also opens
up the a1-h8 diagonal for potential queen invasion. However, black can play, 1.
... Qf6+, and take control of that diagonal, and at the same time offering more
protection to the black king. Pushing the black queen like this has gained
white nothing. Black must still play carefully, but the big opportunity for
white has been missed
.
** Alarm bells
.
1. White has a queen and a rook located on the 2 fully open centre files. Black
has queen and rook doubled on the f-file. Generally speaking both are
considered beneficial
.
2. Despite the black heavy piece doubling on the f-file, black was in trouble.
Once the white queen penetrated to the 8th rank, vital flight squares for the
black king were denied, and the black queen and rook became helpless spectators
.
3. The apparent black kingside defensive pawn structure and blockade, was soon
destroyed, by the actively placed white rook. What appears to be a static area
of the board, can quickly become mobile, once the inspiration to open the
position comes to mind
.
4. Sacrifices can come in a range of flavours. If the white move, 2. Rxg5+,
could be regarded as a Madras curry, hot but not the hottest, then the pawn
sacrifice, 3. h6+, could be described as an ice-cream sundae. Cool and sweet
.
5. Compare and contrast each bishop. The black bishop points into an empty
white kingside. The white bishop controlled 2 vital potential flight squares.
Attacking down an empty diagonal can be just as powerful as having a target
somewhere in the distance
.
Paul Benson.
-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 16/07/2012 16:07
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem BWTC427
Good Morning Puzzlers,
Another checkmate problem, but from a different part of the file.
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 "1001 Brilliant Ways to
Checkmate" .
This problem can also be obtained from G. Ossimitz's chess page at:
http://wwwu.uni-klu.ac.at/gossimit/c/chess.htm
Problem BWTC 0427
White to move
FEN:
5k2/
pbp2r2/
1p5p/
4R1pP/
1PP5/
8/
PKBQ1q2/
8
w - - 0 1
Short Algebraic Problem Setup:
White: Kb2, Qd2, Re5, Bc2, Pa2, Pb4, Pc4, Ph5
Black: Kf8, Qf2, Rf7, Bb7, Pa7, Pb6, Pc7, Pg5, Ph6
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07:34:00
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