[blind-chess] Spoiler Alert Problem WAC051
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Fri, 14 Jan 2011 05:04:05 -0000
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 c3 and e5 pawns are isolated, and in just one
move by black, could be forked by the queen moving to c7. If either pawn is
lost, the white centrally placed pieces will come under pressure. The e5 pawn
is restricting the movements of both the black rook and king. The h4 pawn is
preventing the black queen from landing on g5, which would force the white
queen to retreat. The king is safe on g1. The queen on h5 is actively placed
for an attack. The remaining 3 white pieces, are all centrally located, and
putting considerable pressure on the central black light-squared pawn chain.
Since white is an exchange and 2 pawns down, something must be done with all
this piece activity, or black will slowly but surely challenge active pieces,
forcing them back, and then the material imbalance will begin to show
.
Black: Three pawn islands. The central light-square "V", formation is tricky to
assess. All of the pawns are blockaded by white, but in turn, black is hoping
the 3 pawns will stifle the white piece activity, permitting the black pieces
to develop behind them, and in time push back the white central masses. These 3
pawns also restrict the mobility of their fellow bishop. The h6 pawn is
isolated and could very quickly become a point of attack. The king, is looking
a little lonely, no immediate piece cover. He can not, at the moment, run away
towards the centre, should threats from white mean he has to escape from the
kingside. The remaining black pieces are passively placed on their back rank,
the kindest way of assessing them, is to say they all have opportunities to
improve themselves
.
** Hints section, 5 hints
.
** Hint 1, to find the key move
.
Imagine a vital, black defensive line-blocking unit,could be simply removed
from the board
.
** Hint 2, to find the key move
.
If you have imagined correctly, about which unit to remove, white would have
mate in 2 moves, in 2 different ways
.
** Hint 3, to find the key move
.Analysing combinations can be fun, but save the fireworks for a better occasion
.
** hint 4, to find the key move
.
Think laterally, literally
.
** 5th and final hint, to find the key move
.
It is a quiet invasive move
.
** Proposed solution to WAC051
.
With the centrally massed pieces, combined with the active queen, one would
expect a tactical hammer-blow somewhere on that black light-squared pawn chain.
However, this is not so this time. The white rook makes a subtle sideways
shuffle with, 1. Rg4+, leaving black to choose which mate in 3 moves is
preferable, if the rook is captured immediately, or a slightly longer finish,
by giving up the queen first
.
Firstly, capturing with, 1. ... fxg4. This only brings the previously stifled
white bishop on d3 into the game. Now, 2.
Qg6+, the queen invades decisively. The black reply is forced, 2. ... Kh8 3.
Qh7+ mate
.
Secondly, black does not capture, but this just allows the combined white queen
and rook to end the game. If 1. ... Kh8, simply 2. Qxh6+ mate. Instead, 1. ...
Kh7, lasts a move longer, 2. Qg6+ Kh8, and white has 2 checkmating replies.
There is either, 3. Qg7+ mate, or, 3. Qxh6+ mate. Another example of heavy
pieces combining, to create an edge of the board restricted mate
.
Lastly, giving up the queen with, 1. ... Qg5, and the simplest capture is with
the pawn, and leave black with the same tactical problems that arise from
capturing the rook. If 2. hxg5 fxg4, the mate occurs again with, 3. Qg6+ Kh8 4.
Qh7+ mate. So, after 1. ... Qg5 2. hxg5, black can try, 2. Rg8. White has has
queen and knight against a rook. There is no quick mate or forcing sequence.
Here is a sample line, there are too many variations to list them all, 3. Qxh6+
Kf7 4. Qh7+ Rg7 5. g6+ Kf8 6. Qh8+ Rg8 7. Qf6+ Ke8 8. Bb5+, bringing another
piece into the attack, though continuing on the kingside will win more
material. So after, 8. ... Bd7 9. Qf7+ Kd8 10. Qxd7+ is mate
.
** Condensed proposed solution
.
1. Rg4+ fxg4 2. Qg6+ Kh8 3. Qh7+ mate
.
** Other tactical variations considered, and rejected
.
A typical way for white to increase the pressure against the black pawn chain
is, 1. g4. It should be obvious that black can not afford to capture 1. ...
fxg4, which would bring both the white rook and bishop into the game. Instead,
after 1. g4, black has 1. ... Qe8. This forces matters, so 2. Qxe8 Rxe8, and
white can win a pawn with 3. gxf5 exf5, and now 4. Nxf5+, seems the correct
minor piece capture, since instead 4. Bxf5, leaves the e5 pawn hanging to the
e8 rook. Now simply, 4. ... Bxf5 5. Rxf5 Re6, and white can do little against
either 6. ... Rae8, or 6. ... Rf8 next move, winning the e5 pawn
.
Piece sacrifices at any point on the black pawn chain, seem to permit mass
liquidation, which leaves white a rook down, but more importantly, no support
for the white queen to continue an attack. The order of minor piece capturing
seems to make no difference. Black has 3 defenders on the f5 pawn, so if white
starts capturing, there is no point where the sequence can stop, white just has
to keep going. So if, 1. Nxf5+ exf5 2. Bxf5 Bxf5, and white can do little else
than, 3. Rxf5 Rxf5 4. Qxf5, no attack left, and black just plays 5. ... Qe7,
intending 6. ... Rf8 next move. If white tries 6. h5, aiming for a queen
invasion on g6, simply, 6. ... Qf7, and white has nothing left
.
If instead, 1. Nxe6+, nothing really changes, since, 1. ... Bxe6 2. Bxf5 Bxf5,
just transposes into the line discussed above
.
** Alarm bells
.
1. Black has adopted the strategy of trying to hide behind a pawn chain, while
capturing material, in the belief white has no way through. This demands good
positional judgement
.
2. Following the black strategy, just given in point 1 is on the risky side.
Sometimes, an opportunity appears for the attacker, which was very difficult to
foresee, several moves prior to a decisive plan emerging. Fortune often favours
the bold
.
3. White is 4-0 ahead in piece activity. Accepting material gain, but falling
so far behind in development like this, will almost always be a serious
strategic mistake, which should be punished tactically
.
Paul Benson.
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 WAC051
White to move
FEN Problem Setup:
r1bq1r2/
pp4k1/
4p2p/
3pPp1Q/
3N1R1P/
2PB4/
6P1/
6K1
w - - 0 1
Short Algebraic Problem Setup:
White: Kg1, Qh5, Rf4, Bd3, Nd4, Pc3, Pe5, Pg2, Ph4
Black: Kg7, Qd8, Ra8, Rf8, Bc8, Pa7, Pb7, Pd5, Pe6, Pf5, Ph6
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