[blind-chess] Spoiler Alert: Problem BWTC428
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Sun, 29 Jul 2012 17:55:15 +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 and 2 pawns ahead. There are no pawn
weaknesses to comment on, except for the d4 pawn, which is undefended and
attacked by the black queen. The king is lacking piece protection, but this is
not important, as black can not create any threats in his direction. The queen
is excellently placed on e7, but is challenged by the black queen, and might
not be able to remain on the 7th rank for much longer. The a1 rook is a couple
moves away from developing on a central file. The g7 rook is aggressively
placed, combining with the queen on the 7th rank, creating a number of
interesting attacking opportunities. The c1 bishop is yet to develop, though
there are several good squares awaiting this piece. The c4 bishop is undefended
and attacked, by the black b6 knight, but is however well placed on the a2-g8
diagonal, pointing directly into the black kingside
.
Black: Two pawn islands, and an exchange and 2 pawns down. There are no pawn
weaknesses to comment on, however, the kingside pawn structure has a serious
dark square weakness, in particular the h6 square. The king is in severe
difficulty, only a knight on f6 offering defensive support, against the nearby
presence of the white queen and rook, as well as the raking effect of the white
c4 bishop. As if that was not bad enough, the black king his trapped in a
corner, with no legal moves. The queen on d6 is attacking the white d4 pawn,
though capturing this pawn will lead to instant loss. The black queen could if
permitted, exchange itself for the white queen, which would remove much of the
white attacking pressure, but being an exchange and 2 pawns down, a queen
exchange is almost always deemed undesirable for the player behind in material.
The a8 rook is out of play. The c8 bishop needs to develop and challenge the
powerfully placed white c4 bishop. The b6 knight is attacking the undefended
white c4 bishop. The f6 knight is attempting to fight off the aggressively
posted white queen, rook, and c4 bishop, an almost impossible task
.
** Hints section, 5 hints
.
Hint 1, to find the key move
.
Richard III, allegedly offered to trade his kingdom for what?
.
Hint 2, to find the key move
.
If this were an Equestrian event at the Olympics, the judges would be seeking
to disqualify this competitor
.
Hint 3, to find the key move
.
Perhaps an overloaded individual should be given early retirement
.
Hint 4, to find the key move
.
Find a mate threat, and what is preventing that threat, and then what?
.
Final hint, to find the key move
.
Big rewards often demand the biggest investment
.
** Proposed solutions to BWTC428
.
White has excellent attacking potential, due to the doubled queen and rook on
the 7th rank, which is strengthened by the c4 bishop, and despite appearances
because it is undeveloped, the c1 bishop is also assisting. It should not come
as a surprise, that there are 2 variations which lead to checkmate. Both are
imaginative, though the first choice is somewhat more appealing
.
Solution 1
.
White has a rather spectacular move, which makes this variation the first
choice solution. It goes, 1. Qxf6, the white queen removes the only defender in
the black kingside, but surely she is not protected here? Correct, black can
play, 1. ... Qxf6, but would receive a shock with, 2. Rg8+ mate. The white
queen sacrificial capture of the black f6 knight, to weaken the g8 square would
be fully justified. However, black does not have to capture on f6.. Oh, and
while black is wondering what to do, it is worth pointing out that white now
has a threat of, 2. Rg8+ double discovered check and mate. It seems that black
has 2 replies. Firstly, 1. h5, freeing the h7 square for flight, but after 2.
Rg8+, a double check, Kh7 3. Rh8+ mate would occur. Instead, secondly, black
could try, 1. Nxc4, removing the attacking supporter for the g8 mate threat.
White has the option to simplify matters with, 2. Rxg6+, forcing black to reply
with, 2. Qxf6, and now after, 3. Rxf6, white is 3 pawns and an exchange ahead,
clearly winning but not checkmating. So after, black plays, 1. Nxc4, white
instead creates several unstoppable mate threats with, 2. Qf7, doubling against
the weak h7 pawn and threatening, Rxh7+ mate, and also threatening either,
Qg8+, or, Rg8+, both being mate. Black can only lengthen the game with, 2.
Qxh2+, rather pointless really. White captures with, 3. Kxh2, and black can
prevent the mates on the g8 square with, 3. ... Be6, the a8 rook now covering
g8, but allowing, 4. Rxh7+ mate.
.
Solution 2
.
White can be more subtle, and instead of boldly snatching material, can demand
that black be forced to receive material. White plays, 1. Qe8+, which offers
both the queen and the g7 rook to black, and also powerfully demonstrates, the
potential weakness of not completing queenside development. So, what can black
do here? Firstly, the greedy, 1. ... Nxe8, removes the protection of the g8
square, and allows, 2. Rg8+ mate. Instead, black can give away material, by
interposing with, either, Ng8, or, Qf8, followed by, Ng8, but in each case, the
white queen just captures whichever piece chose to intervene, ultimately
leading to a mate on the g8 square. Lastly, so, it seems if black wishes to
struggle on, the g7 rook must be captured, 1. ... Kxg7. Note here that the
black king still has no flight squares, that h6 square is covered by the lazy,
c1 bishop. White proceeds with the plan by forcing the black king back into the
corner, where again the king will have no legal moves. So, 2. Qf7+ Kh8. Note
here, that with the white queen placed, "a knight's jump", away from the black
king, any check by white, other than from the queen who must stay in place on
f7, will be mate. So, now the ecclesiastical "cavalry" charges in with, 3. Bh6.
White now threatens mate on g7 with both the queen and bishop. If black tries
to defend the g7 square with the f6 knight, 3. ... Ne8, or, 3. ... Nh5, then
yet again that g8 square has lost it's defensive cover, and, 4. Qg8+ mate,
would occur. Black can only resort to desperation with, 3. ... Qxh2+. Normally,
such queen throw-aways have no meaning. However, this time there is some
validity. After, 4. Kxh2 Ng4+, the black knight forks white king and h6 bishop.
Play continues with, 5. Kg1 Nxh6, and now the black knight has prevented the
immediate mate on g7, and also covered that perpetually threatened g8 square,
and rather cheekily attacked the white queen. White concludes with, 6. Qf6+
mate, the c4 bishop covers the g8 flight square. That bishop on c4, has been a
passive thorn in the side for black for virtually every move in this solution.
If, "Chess Piece Oscars", exist for supporting roles during a combination, I
nominate the c4 bishop for such an award
.
** Condensed proposed solution 1
.
1. Qxf6 Nxc4 2. Qf7 Qxh2+ 3. Kxh2 Be6 4. Rxh7+ mate
.
** Condensed proposed solution 2
.
1. Qe8+ Kxg7 2. Qf7+ Kh8 3. Bh6 Qxh2+ 4. Kxh2 Ng4+
5. Kg1 Nxh6 6. Qf6+ mate
.
** Other tactical variations considered, and rejected
.
Option 1: White can simplify the position with, 1. Qxd6, effectively giving up
the search for checkmate. This move leads to a decisive advantage, and is a
safe choice, but misses the big chance of immediate victory. Play would
continue, 1. ... cxd6. Now, white has 2 pieces attacked, the g7 rook and the c4
bishop. Both can be defended with, 2. Rc7. Black can now try, 2. ... Ne8, which
attacks the c7 rook, and the rook has no means to move along the c-file, and
therefore the white bishop is going to lose it's defence from the rook. White
is however still winning, as, 3. Re7, attacks the undefended black e8 knight.
So, both black and white have a piece attacked, and the best try for black is
now, 3. ... Bf5, protecting the e8 knight with the a8 rook. White now
consolidates with, 4. Bb3, leaving white still an exchange and 2 pawns ahead,
and winning in the long term
.
Option 2: White unnecessarily grabs another pawn with, 1. Qxc7, protecting the
c4 bishop, and also removing the defender of the black queen. If black trades
queens with, 1. ... Qxc7, play could follow the idea of Option 1 given above,
but with white having an extra pawn. However, there is a trick here. The white
queen is overloaded, defending both the c4 bishop and the g7 rook. Black
ignores the attack against the undefended queen, by capturing with, 1. ...
Nxc4, which places a backward guard on the black queen. White has just lost a
piece, since if, 2. Qxc4 Kxg7, white would lose a rook. While having rook and 3
pawns against 2 knights is very favourable and should be winning, there is much
work to be done by white. So, white capturing with, 1. Qxc7, is extremely
careless
.
Black had an alternative on move 1, so after, 1. Qxc7 Qxd4, placing a double
attack on the white c4 bishop had to be considered. White must be careful here.
The casual, 2. Bh6, trying for a dark square checkmate, apparently loses a
piece to, 2. ... Nxc4. Note, black does not capture the c4 bishop with, 2. ...
Qxc4, which allows, 3. Rxh7+ Nxh7 4. Qg7+ mate. So, after black captures with,
2. ... Nxc4, the attempted mate with, 3. Rxh7+, forces the black reply, 3. ...
Nxh7, as the black queen on d4 now guards the g7 square, and white is now 2
pieces down for 3 pawns, which seems rather sad for white. However, there is a
sting in the tail here. The white queen and bishop are combining to threaten
mate on the g7 square. This is prevented by the black queen on d4. However, the
black queen is also the only defender to the c4 knight, and as such is
overloaded. White can regain a piece with a quiet move, 4. c3, and the black
queen can not prevent the mate on g7, and protect the c4 knight. So after, 4.
... Qf6 5. Qxc4, white now has 3 pawns for a piece, a tricky endgame for both
players to test each other will arise
.
So, it seems that, 1. Qxc7 Qxd4, leaves white having to play, 2. Bb3, remaining
an exchange and 2 pawns ahead. This is still good for white, however black is
beginning to unravel, and white will have to carefully complete development
before starting to mount pressure on the black position again
.
Option 3: White can combine natural development and threat with, 1. Bg5,
leaving the c4 bishop under attack, but placing a serious threat to remove the
black f6 knight, which is the only piece preventing immediate kingside disaster
for black. Black can not afford to lose the f6 knight, so, 1. ... Nbd7, seems
necessary. White now has a fantastic position, as black is even further behind
in completing development. Simply, 2. Re1, creates problems for black, as now
white is threatening, 3. Rf7, which places too much pressure on the f6 knight,
triply attacked and only doubly defended. Black must accept that after, 2. Re1,
that trading queens, 2. ... Qxe7, is virtually forced. However, after, 3.
Rexe7, white has an overwhelming position, and should quickly win material or
give checkmate
.
Option 4: White can try to bludgeon a way through with, 1. Rxh7+. This fails
against good defence, but the ideas are worth a little exploration. Black must
capture with, 1. ... Nxh7, since the flight square, g8, is covered by the white
c4 bishop. White now plays, 2. Qe8+, and black must avoid the blunder, 2. ...
Kg7, as white would then mate with either, 3. Qf7+ Kh8 4. Qg8+ mate, or, 3.
Qg8+ Kf6 4. Qf7+ mate. Note how the dark squares of, h6 and g5, are denied
black by the undeveloped white c1 bishop
.
So, after 1. Rxh7+ Nxh7 2. Qe8+, how does black avoid these mates? Simply
blocking the check with, 2. ... Qf8, stops the white attack. Note, if instead,
2. ... Nf8, white has, 3. Bh6, creating some very strong threats around the
black king again. Once black blocks with, 2. ... Qf8, white is now a piece
down, has queens facing each other, and the c4 bishop is still under attack. So
black has escaped the worst, and has a piece for 3 pawns. This is now rather
messy, but hopefully demonstrates how care must be taken, to restrain
over-optimistic ideas, when in complete control of a position
.
** Alarm bells
.
1. Black has made decisions earlier in the game, which have led to only one
piece, the f6 knight, defending the king. This is exacerbated by the lack of
queenside development, permitting white 2 quick finishes to the game
.
2. The black f6 knight is single-hoovedly, attempting to halt the threats
created by the coordinated efforts of the white queen, rook, and c4 bishop, not
forgetting the latent power of the undeveloped c1 bishop. Such overloading
should inspire the attacker to search for 1 or more decisive combinations
.
3. In solution 2, move 1. Qe8+, the white rook, while excellently placed on g7,
could not contribute further to achieve mate. White found a means of
eliminating the non-contributing rook, which permitted a lesser value piece,
the c1 bishop, to join the attack, to create the unstoppable double mate
threats. The supposedly lesser-value piece, a bishop, showed the apparently
lesser-valued movement along diagonals, was the power required here for success
.
4. In solution 2, move 1. Qe8+, the focus point for the initial mating attack,
the g7 square, is occupied by a white rook. White forces black to capture the
rook, followed by transferring the queen to the safety of the f7 square. The
now unoccupied g7 square becomes the focus for the mating attack. Just because
a square is occupied, it does not mean that square can not be the target square
for mate. Think in terms of, where can mate occur and then how to bring it
about, rather than mate can not occur there, because the square is occupied
.
5. In solution 2, move 1. Qe8+, the totally restricted location of the black
king, permitted white to find a forcing sequence of moves, to offer the dark
square bishop the chance to invade on h6 creating unstoppable threats
.
6. The white bishop on c4, totally controlled important light squares around
the black king. Leave such powerful pieces unchallenged at your peril
.
Paul Benson.
-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 23/07/2012 16:41
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem BWTC428
Good Morning Puzzlers,
Another checkmate problem.
This problem is from Mario Lang's puzzle web page at:
http://delysid.org/chess/epd.cgi
and is from Fred Reinfield's book "1001 Brilliant Ways to Checkmate" .
Problem BWTC 0428
White to move
FEN:
r1b4k/
ppp1Q1Rp/
1n1q1np1/
8/
2BP4/
P7/
1PP2PPP/
R1B3K1
w - - 0 1
Short Algebraic Problem Setup:
White: Kg1, Qe7, Ra1, Rg7, Bc1, Bc4, Pa3, Pb2, Pc2, Pd4, Pf2, Pg2, Ph2
Black: Kh8, Qd6, Ra8, Bc8, Nb6, Nf6, Pa7, Pb7, Pc7, Pg6, Ph7
Other related posts:
