[blind-chess] Spoiler Alert: Problem WAC120
- From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Sat, 24 Jan 2015 19:26:41 -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 d5 pawn is isolated, it can not be protected by
another white pawn, and is defended only once while being under attack from the
black queen, b7 bishop and c7 knight. This 3 against 1 majority attack means
black can capture this pawn in a couple of ways whenever deemed desirable. The
g5 pawn is contributing to attacking pressure on the black kingside. The king
on c1 is not in immediate danger, however the advanced position of the black
queenside pawns in a 3 against 2 majority means black will be able to open
lines quickly. Once lines open in front of the white king, the lack of
protecting white pieces will be an important factor. The white queen is very
aggressively placed on h6, but needs assistance from other pieces to create
threats. The d1 rook is insufficient to protect the d5 pawn. The h1 rook could
either remain where it is and support the advance of the h-pawn or consider
moving sideways to either the g-file or e-file as desired. The c2 bishop is the
only piece in front of the white king offering any form of protection, but does
also perform an attacking role by pressuring the black f5 pawn. The bishop on
f6 is aggressively place, and as the black dark square bishop is no longer on
the board it will be difficult to challenge. The knight on f3 is unprotected
and could become a target of the black b7 bishop should the d5 pawn be captured
.
Black: Three pawn islands. The advanced queenside pawns offer good attacking
opportunities, though this will take a couple of moves to begin line-opening.
The d6 pawn is backward, not easy for white to attack at the moment, but is at
least working to keep a white knight out of the e5 square. The f5 pawn is
isolated but is blocking the very important b1-h7 light square diagonal. The h7
pawn needs more protection than presently given. The king is very restricted,
should the white attack become dangerous then the opportunity to run across the
board to the queenside is presently not available. The queen on f7 is joining
in the attack on the white d5 pawn and defending the g7 knight, but might
become vulnerable to attack from lesser value white pieces. The f8 rook is not
assisting the defence of the kingside and could be considered as hindering any
potential flight route for the black king. The a8 rook has not developed but
might find remaining on a8 to assist line-opening in front of the white king.
The b7 bishop is part of the triple attack against the under-protected white d5
pawn. The c7 knight is similarly part of the pressure on the white d5 pawn. The
g7 knight is protecting the f5 pawn, but is blocking protection of the h7 pawn
along the black 2nd rank
.
** Proposed solution to WAC120
.
White is about to lose the d5 pawn and there is also the advancing black
queenside pawns to take into account. Something quick is needed. White can
create a double attack with, 1. g6, after which black can consider 3 responses
.
Option A: Black gets greedy with, 1. Qxf6, winning a bishop. Unfortunately the
advance of the white g-pawn created a double attack against the under-protected
black h-pawn, permitting, 2. Qxh7+ mate, the g6 pawn guards the f7 flight square
.
Option B: Black captures on g6 with, 1. ... Qxg6. Now both the white queen and
f6 bishop are attacked and unprotected. White neatly solves both problems with,
2. Bxg7. If black trades queens with, 2. ... Qxh6 3. Bxh6, then white wins a
piece in the sequence. Instead after, 2. Bxg7 Qxg7, white shows the value of
opening up lines in front of the opposing king with, 3. Rhg1, pinning the black
queen to her king. Since the only material invested so far by white is a pawn,
this position is now decisive for white. Black might attempt to hold matters
with, 3. ... Rf7, but after, 4. Bxf5, another white piece joins the attack.
White is in no hurry to play, Rxg7+, the black queen can not escape. Further
white invasion will occur, this is a won position for white.
Instead after, 1. g6 hxg6, white demonstrates the value of square clearance
with, 2. Ng5, occupying the now vacated square. The invading white knight has
created a double threat, an attack against the black queen and supported a
queen check on the h7 square, which in the present position would be mate. So,
with black to move, 2. ... Qxf6 3. Qh7+ is mate, the white knight guards the
potential f7 flight square. Instead after, 2. Ng5 Nh5, giving protection to the
h7 square from the black f7 queen, but permitting, 3. Qh8+ mate.
It seems the only way to avoid mate after, 1. g6 hxg6 2. Ng5,is to give the
king a flight square with, 2. Rfc8, but this simply loses the black queen with,
3. Nxf7
.
** Condensed proposed solution
.
1. g6 Qxg6 2. Bxg7 Qxg7 3. Rhg1
.
** Other tactical variations considered, and rejected
.
White is about to lose the d5 pawn, something must be found quickly, but there
is not much to inspire
.
Option 1: Advancing with, 1. h4, just allows, 1. ... Bxd5, and the f3 knight is
now under attack. Black also has theoption of, 1. ... Qg6, challenging queens
before capturing on d5. Either way, white is worse
.
Option 2: White prepares for kingside play with, 1. Rhg1. Again, black can
postpone winning the d5 pawn and instead challenge with, 1. ... Qg6. White can
try, 2. Nh4 Qxh6 3. gxh6, pinning the black g7 knight. Unfortunately, black
has, 3. ... Rxf6, and while white can win the black knight with either rook or
h-pawn, this is not decisive for white, and the d5 pawn is still a problem
.
Option 3: White tries to activate the potential target f3 knight with, 1. Nh4,
doubly attacking the black f5 pawn and supporting the advance of the g-pawn.
Unfortunately once the white knight moves to h4, then the ideas of weaving a
mating attack or winning the black queen with a later, Ng5, has been
voluntarily taken away. White might indeed mount some pressure after, 1. ...
Bxd5 2. Rhg1, but again this is not quickly decisive for white
.
Option 4: White might pressure the f5 pawn with, 1. Nd4, but after, 1. ... Qg6,
the white queen is either repulsed, or next move black can win material with,
2. ... Rxf6, exploiting the overloaded white g5 pawn protecting both the f6
bishop and queen
.
** Alarm bells
.
1. A restricted king needs careful consideration, it might not have a flight
route as opposing pieces invade
.
2. One piece or pawn vacating a square permits another to occupy that square.
Perhaps reverse thinking can be applied. Imagine a different value piece
sitting on an an already occupied square, and if that seems favourable,
consider moving the current occupant
.
3. Apparently blocked lines can open up in a few moves, usually most effective
when each move for the attacker carries a threat which must be answered
.
Paul Benson.
-----Original Message-----
From: Richard Dinger - Email Address: dmarc-noreply@xxxxxxxxxxxxx (Redacted
sender "rrdinger@xxxxxxxxxx" for DMARC)
Sent On: 08/01/2015 15:45
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC120
Problem WAC 120
White to move
FEN:
r4rk1/
1bn2qnp/
3p1B1Q/
p2P1pP1/
1pp5/
5N1P/
PPB2P2/
2KR3R
w - - 0 1
Short Algebraic Problem Setup:
White: Kc1, Qh6, Rd1, Rh1, Bc2, Bf6, Nf3, Pa2, Pb2, Pd5, Pf2, Pg5, Ph3
Black: Kg8, Qf7, Ra8, Rf8, Bb7, Nc7, Ng7, Pa5, Pb4, Pc4, Pd6, Pf5, Ph7
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