[blind-chess] Spoiler Alert: Problem WAC097
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Mon, 17 Sep 2012 13:10:51 +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 2 pawns up. The queenside pawns have no
weaknesses, however the invasion of the black queen and rook, into the white
position, has placed the unprotected a2 and c3 pawns in danger of capture. The
h2 pawn is isolated, however is in no danger. The king has the presence of the
white queen and rook to assist in protection, as well as the backward defence
from the e5 bishop. However, he also has no mobility, a factor which could
prove problematic should the black queen and rook become even more threatening.
The queen is placed on the g-file, and is pinning the black knight to the king.
She is also under attack from the black e2 rook, and something must be done
about this. The rook on g1 is offering support to the white queen, doubling
down the g-file, though presently black has a knight preventing white from
invading up the file. The bishop on e5 is attacked by the black g6 knight,
however, at presently the knight is pinned, so the bishop is safe from
immediate capture. The bishop controls some dark squares around the black king,
which might prove to be useful
.
Black: Three pawn islands and 2 pawns down. The a6 pawn is probably the
weakest, the f7 and h6 pawns have some protection from the black king being
close by. The king is rather uncomfortable. The doubled attack down the g-file
is temporarily blocked by the g6 knight, though remember, pieces can be pushed
around. The king also has the white bishop on e5 to contend with, the dark
squares of g7 and h8 could be difficult to defend. The black queen is
aggressively placed on the white 3rd rank, and can capture the white c3 pawn is
desired. The rook on e2 is even more aggressively placed on e2, both attacking
the white a2 pawn, and more importantly, the white queen on g2. The knight on
g6 is very uncomfortable, being doubly pinned down the g-file by the white
queen and rook, though it will take white several moves to endanger this knight
with an advance of the h-pawn
.
** Hints section, 5 hints
.
Hint 1, to find the key move
.
Sometimes, an irresistible force, when confronted by an immoveable object, just
pragmatically goes around it
.
Hint 2, to find the key move
.
Dark square weaknesses deserve exploitation, but which dark square should be
the target, or perhaps, targets?
.
Hint 3, to find the key move
.
Had the white queen visited a fortune-teller before this game, she would have
found out she was going on 2 long journeys abroad, resulting in a dark ending
.
Hint 4, to find the key move
.
Sometimes a line can be blasted open, and other times a forceful but polite
request will suffice. No need for a display of strength here
.
Final hint, to find the key move
.
Bobby Fischer "quote": "Patzer sees check, patzer gives check". Clearly, Bobby
did not have this position in mind
.
** Proposed solution to WAC097
.
White has managed to achieve a 2 pawn advantage, however, the aggressive black
queen and rook will soon win back at least 1 pawn, if not more. White can not
sit back and simply try to steer for an ending. The attacked white queen must
move, and can invade with, 1. Qa8+, which forces the black reply, 1. ... Kh7,
the dark squares of g7 and h8 being controlled by the white e5 bishop. Note,
the black g6 knight is still pinned down the g-file, but now by the white g1
rook, so blocking the check with, Nf8, is not legal. The black king on h7 is
now totally immobilised, and as such, is very vulnerable to forcing moves.
White finds the inspiration to play, 2. Qh8+, and since the black king can not
capture the queen, as she is protected by the white bishop, the only reply for
black is, 2. ... Nxh8. White must have a reason for this monarchic generosity.
The black knight has been forced, though others might say politely invited, to
vacate the g-file, which permits the white rook an entry with, 3. Rg7+ mate.
The black king was first driven to a square of immobility, and then the black
knight was deflected with a queen sacrifice to h8, opening up the g-file
.
** Condensed proposed solution
.
1. Qa8+ Kh7 2. Qh8+ Nxh8 3. Rg7+ mate
.
** Other tactical variations considered, and rejected
.
The white queen is under attack, and while an attacked piece is not legally
compelled to move, in this instance there are no surprising non-royal moves to
explore. There are 6 plausible white queen moves, and 3 will be examined here
.
Option 1: White might try to defend the c3 pawn indirectly with, 1. Qg3. This
turns out to be a massive disaster. White has totally lost control of the light
squares around the white king. Blacck replies, 1. ... Qe4+, and with the white
king being restricted by his own units, white has to block the check with
either the queen or rook. If, 2. Qg2, simply, 2. ... Rxg2, black wins a queen
for a rook. Play could continue, 3. Rxg2, and black can play simply with, 3.
... Qb1+ 4. Rg1 Qxa2, and have a material win. Instead after black, 1. ...
Qe4+, white blocks with, 2. Rg2, black has, 2. ... Re1+, and since the g2 rook
is pinned, white has no choice but to give up queen for a black rook with, 3.
Qxe1+, and after, 3. ... Qxe1+ 4. Rg1 Qe4+ 5. Rg2 Qb1+ 6. Rg1 Qxa2, black has
the same material win as just given above
.
Option 2: White tries to infiltrate into the black position with, 1. Qf1,
intending to invade on f6, with a threat of mate on the g7 square. This is far
too optimistic and very slow, the presence of the aggressive black queen and
rook have far too much power in the centre, and this can not be ignored. Black
plays, 1. ... Qe4+, and if, 2. Qg2, this transposes into the line given in
Option 1 above, where black wins. Instead after, 1. ... Qe4+, white blocks
with, 2. Rg2. Now black again wins material but this time with, 2. ... Re1,
pinning the white queen to her king. White should immediately break the pin on
the g2 rook with, 3. Kg1, but after, 3. ... Rxf1+ 4. Kxf1 Qb1+, black will win
some queenside pawns, and black is winning
.
Option 3: White throws the queen into the black queenside with, 1. Qc6, which
keeps control of the long light square h1-a8 diagonal, and also backwardly
guards the c3 pawn. Black can win a pawn back with, 1. ... Rxa2, but this
permits white, 2. Qe8+ Kh7, note the black knight can not play, Nf8, to block
the check as it is pinned. Now simply, 3. Qxf7+ mate. So, it seems that after,
1. Qc6, black should protect the f7 pawn with either, 1. ... Rf2, or, 1. ...
Qf2. Note, in the latter case black is not threatening mate on h2, because the
e5 bishop backwardly guards the h-pawn. So with white to play move 2, White
must be careful about moving the queen off the long h1-a8 diagonal, as black
would then play, Qf3+, creating a mating net. With, 1. Qc6, white is not
immediately losing, but has missed the opportunity for a quick checkmate
.
** Alarm bells
.
1. The doubling of the white queen and rook down the g-file, created a double
pin on the black knight. This meant that when the white queen vacated the
g-file, the pin was still in place, albeit now from the white rook
.
2. The direct route of entry for the doubled white heavy pieces up the g-file
was blocked. So, the white queen took a scenic route, via the a8 square to
invade the black position
.
3. A king on the edge of the board has a maximum of 5 potential flight squares.
When both of the squares either side of the king, on the edge file/rank, here
it is the h-file, are occupied, then the restricted mobility should alert one
to a possibility of checkmate on the adjacent file/rank, here it is the g-file
.
4. The white queen, from her perspective, made a suicidal move. Immediately
halting analysis when such suicidal moves are initially considered, will miss
opportunities for a quick and satisfying victory. Analyse further than those
apparent suicidal moves
.
5. The white queen sacrificed herself to deflect the black knight, to fully
open up the g-file. Sacrifices do not have to include captures, here the motive
was deflection of a blockading defender
.
6. The white bishop on e5 controlled important dark squares around the black
king. Such pieces if allowed to remain unchallenged, are offered the
opportunity to contribute towards inflicting serious damage to the defending
opponent
.
Paul Benson.
-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 11/09/2012 23:55
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC097
Good Afternoon Puzzlers,
Another WAC series problem.
This problem is from Mario Lang's puzzle web page at:
http://delysid.org/chess/epd.cgi
Problem WAC097
White to move
FEN Problem Setup:
6k1/
5p2/
p5np/
4B3/
3P4/
1PP1q3/
P3r1QP/
6RK
w - - 0 1
Short Algebraic Problem Setup:
White: Kh1, Qg2, Rg1, Be5, Pa2, Pb3, Pc3, Pd4, Ph2
Black: Kg8, Qe3, Re2, Ng6, Pa6, Pf7, Ph6
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07:34:00
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