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. The queenside paws have no weaknesses. The g3 square
is a hole on the kingside, but exploitation of such a weakness is far from
imminent. The king is short of piece cover and while the black forces might not
appear to be coordinating for a kingside assault, there might be some danger of
which to be aware. The queen is waiting to join the action, as are both the a1
and f1 rooks. The d4 bishop is pinned to the king by the black b6 bishop. The
e2 bishop is defended by both the white queen and c3 knight, but is also rather
uncomfortable on the fully open e-file, where it is attacked by the black e8
rook. The c3 knight protects the e2 bishop but can be traded off by the black
d5 knight
.
Black: Two pawn islands, there are no weaknesses in either island. The king is
short of piece cover but the white forces are not coordinated to create any
threats. The queen can move into the kingside, either the g5 or h4 squares,
from where she will begin to create some pressure against the white king. The
a8 rook is yet to join the game. The e8 rook is actively placed on the fully
open e-file and attacking the twice protected white e2 bishop. The b6 bishop
has an x-ray attack on the white king through the white d4 bishop. The c8
bishop is undeveloped but could find itself being sacrificed on the white h3
pawn, should black be able to find active locations on the kingside for the
queen and perhaps the d5 knight. The d5 knight is actively placed and has
several options available, either in the centre or possibly moving into the
kingside
.
** Proposed solution to WAC125
.
White has a slight lead in development, but development without coordination is
not automatically advantageous. Black has an opportunity here to demonstrate
how an apparently well-defended piece can quickly become vulnerable. The focus
is on the white e2 bishop. It is defended twice, but if both these defenders
were unavailable, then the e2 bishop would fall to the e8 rook. We are about to
witness a double-undermining of the white defences
.
Black plays, 1. ... Bxd4+, a forcing move as there is only one sensible reply,
2. Qxd4. Strike 1! The queen has been deflected from the defence of the e2
bishop. Now black further undermines the e2 bishop by removing the remaining
defender with, 2. ... Nxc3. Strike 2! White has several options here, but they
all turn out badly. White must cope with an unprotected queen, an unprotected
bishop, and black being a piece up courtesy of, Nxc3
.
Variation A: White recaptures with, 3. bxc3, which protects the queen but does
nothing for the e2 bishop. black must take care here. Simply, 3. ... Qxd4+,
wins a piece. If instead, 3. ... Rxe2, the black queen is unprotected and white
forces mate with, 4. Qxd8+ Re8 5. Qxe8+ mate. However after the correct move
order of, 3. ... Qxd4+ 4. cxd4 Rxe2, black is a piece up and winning
.
Variation B: White recaptures the black knight with, 3. Qxc3, which leaves the
e2 bishop unprotected and so, 3. ... Rxe2, and black is a piece up and winning
.
Variation C: White deflects the black rook with, 3. Qxd8, and hopes to save the
e2 bishop. No such luck, black knows all about avoiding obvious and automatic
recaptures and plays, 3. ... Nxe2+. A forcing move, it is check. If black had
been unaware of the word, zwischenzug, then, 3. ... Rxd8, could have followed,
and after, 4. bxc3, material equality would have been established, albeit with
a shattered white queenside pawn structure. A zwischenzug is an interpolating
move, that is a move which postpones a material regaining option. Here black
leaves the white queen alone for a move, so after, 3. Qxd8 Nxe2+, black is now
2 pieces up. The sequence ends with, 4. Kf2 Rxd8 5. Kxe2, and black is a bishop
up and winning
.
** Condensed proposed solution
.
1. ... Bxd4+ 2. Qxd4 Nxc3 3. Qxd8 Nxe2+ 4. Kf2 Rxd8
.
** Other tactical variations considered, and rejected
.
Black has some interesting options which do not immediately win, but instead
create interesting play which would test white's defensive capabilities. In
practical terms, some of the below options would probably lead to a win for
black, though much time and many moves would be required
.
Option 1: Black misplays the move order with, 1. ... Nxc3, and as the white d4
bishop is pinned the forced reply is a pawn recapture, 2. bxc3. Now if black
tries, 2. ... Bxd4+, white has 2 choices. Clearly, 3. Qxd4 Qxd4+ 4. cxd4 Rxe2,
and white has allowed a transposition into the proposed solution. Instead
after, 2. ... Bxd4+, white has the superior, 3. cxd4, and the queen remains on
d1 to protect the e2 bishop. Black is slightly better but not winning
.
Option 2: Black tries a knight fork with, 1. ... Ne3, which forks an exchange
so white must play, 2. Bxe3. Black has several choices here such as, 2. Rxe3,
threatening a powerful discovered check. White avoids it with, 3. Qxd8+ Bxd8,
and while black is better here, this is not winning.
Instead after, 1. Ne3 2. Bxe3 Bxe3+ 3. Kh1, black is better but not winning.
Finally after, 1. ... Ne3 2. Bxe3, black might try, 2. ... Qxd1+, removing a
defender of the e2 bishop. There might follow, 3. Rxd1 Rxe3, and it might seem
that the discovered threat of moving the black rook will now win material. It
does not, simply, 4. Kh1, steps out of the danger, and while black is again
better, it is not winning
.
Option 3: Black tries, 1. ... Nf4, creating a double attack on the white e2
bishop, and also putting pressure on the white kingside light-square pawns. The
knight move has also uncovered another attack on the white d4 bishop from the
black queen.
If white retreats with, 2. Bf2, then black can push the queen into the white
kingside with, 2. ... Qg5, threatening mate on the g2 square. White must push
the g-pawn and perhaps, 3. g3, is the better choice. Black can now win material
with, 3. ... Nxh3+ 4. Kg2 Nxf2, when, 5. Rxf2 Bxf2 6. Kxf2, leaves black an
exchange and pawn up, a decisive material advantage.
Instead, 1. ... Nf4 2. Bxb6, gives white fewer problems. After, 2. ... Qxb6+ 3.
Kh1 Nxe2 4. Nxe2 Qxb2, black has snatched a safe pawn. This is favourable for
black and has good prospects for a long term win, though good technique will be
called upon
.
Option 4: Black plays for kingside pressure with, 1. ... Qh4. This immediately
places a double attack on the white d4 bishop. There are also now some threats
beginning with, Bxh3, combined with centralisation of the black a8 rook and a
lift to d6, intending to attack along the black 3rd rank. These threats are a
little slow and will require precise play to break through, if a break through
is possible at all. Black has definite pressure with threats, but white should
have sufficient resources to evade immediate defeat
.
Perhaps after, 1. ... Qh4 2. Bxb6, and should black recapture with, 2. ...
axb6, white should challenge the black queen with, 3. Qe1, and when the black
queen retreats the white queen can transfer to the f2 square. Black is better
but an immediate win is not happening.
Instead play could go, 1. ... Qh4 2. Bxb6 Bxh3, black ignores the white bishop
and starts tactics flowing in front of the white king. This is optimistic as,
3. Bf2, the bishop escapes capture and also pushes away the black queen. Now,
3. ... Qg5, threatens mate on the g2 square. White has a defence with, 4. g3,
and while the kingside is still uncomfortable for white, there is no immediate
mate. Of course, after, 4. g3, black can regain some material with, 4. ... Bxf1
5. Bxf1, leaving an interesting material imbalance. Black has traded a pair of
bishops for a white rook and pawn, not an easy position to play from either side
.
Option 5: Black again plays for kingside activity with, 1. ... Qg5, immediately
threatening, Bxh3. White must be careful here. If black plays, Bxh3, there will
be an immediate threat of mate on g2, a significant difference to when black
tries Option 4 above. If, 2. Bxb6 Bxh3 3. g4 Bxf1, and black has won an
exchange and a pawn. Both players have a bishop attacked and no single move for
white can save material and capture the black bishop. Black is winning here.
So after, 1. ... Qg5, white could try, 2. Kh1. Black can increase the pressure
with, 2. ... Qh4, attacking the white d4 bishop and now the white king is on
h1, the threatened, Bxh3, can be even more dangerous. Complications have
arisen, black will definitely have good attacking options, but a decisive line
to win material or mate is not immediately obvious. It is likely in a game
that, 1. ... Qg5, would give black a good position, but the expanding
analytical tree is so complex it would take Fritz to decide just how good this
queen invasion would be
.
** Alarm bells
.
1. Pieces which appear well-defended may in fact be capable of being
undermined, especially if captures with check appear in the sequence
.
2. Move order in a tactical sequence is important. Swapping the order of
potential captures must be explored to find the most accurate move sequence
.
3. Highlighting potential overloading of defenders early will assist in
avoiding a material-losing combination
.
Paul Benson.
. -----Original Message-----
From: Richard Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 30/04/2015 22:19
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC125
Problem WAC 125
Black to move
FEN:
r1bqr1k1/
pp3ppp/
1bp5/
3n4/
3B4/
2N2P1P/
PPP1B1P1/
R2Q1RK1
b - - 0 1
Short Algebraic Problem Setup:
White: Kg1, Qd1, Ra1, Rf1, Bd4, Be2, Nc3, Pa2, Pb2, Pc2, Pf3, Pg2, Ph3
Black: Kg8, Qd8, Ra8, Re8, Bb6, Bc8, Nd5, Pa7, Pb7, Pc6, Pf7, Pg7, Ph7
