[blind-chess] Spoiler Alert Problem WAC050

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
.
General: This is the most tactically complex problem yet to be posted to the 
list. It is not necessarily the solution that is complex, but the rejected 
lines. You may wish to take the opportunity of studying the rejected lines, as 
studiously as you do for the proposed solution
.
Here is one of the largest material imbalances in a position, since I have been 
commenting on these problems, WAC023 I recall. Clearly white has been investing 
pieces, in order to gain vital tempi for a potential mating net. Black, has 
elected to accept the offered material, believing to be able to fend off the 
white onslaught. Such is the way of cut-and-thrust chess. White must have 
decided to go for mate several moves ago, and black chose not to respond to 
white strategy. Black may well have been able to get some defenders around the 
king in the last few moves, but has instead taken a calculated risk, that white 
is being too optimistic. Let us see who has calculated correctly with regard to 
the soundness of the respective strategies
.
White: For starters, only 2 pieces and a pawn down. Two pawn islands. The 
doubled d-pawns have little future prospects. These pawns will be easy targets, 
come the endgame. The d5 pawn is giving vital protection to the queen. The 
kingside pawns have advanced off the 2nd rank, and a pawn exchange with check 
on g3 is possible.. The king is rather short of protective cover, and would 
succumb to a mating attack, if it were black to move. The queen is extremely 
active, in the heart of the black position, and placed ideally for a decisive 
attack. The b7 rook is ready to move away, giving a discovered check to the 
black king, many choices to be considered there. The e2 rook is working very 
hard. It is defending the king, attacking the black queen, and radiating an 
x-ray attack on the black a2 rook, through the black queen
.
Black: Three pawn islands. The b6 and d6 pawns are unprotected, there is a pawn 
capture with check on g3, further opening up the white king. The black king is 
in a perilous state. No piece defenders within 5 squares, not to mention the 
presence of the white queen and rook. The queen has a rather full existence. 
She is attacked by both a white queen and rook, can capture a rook with check, 
is pinning a rook to the white king, and is in turn, pinned to her own a2 rook. 
Oh yes, and she can take a pawn on d3, a very busy lady indeed. The a2 rook is 
reinforcing the attack through the queen on the e2 white rook. The f8 rook is 
ready to join in a kingside attack, but may well have been better employed on 
the queenside, several moves earlier. The bishop is skulking on h7, ready to 
contribute. The knight is ready to join in the attack. What do you think the 
black King is feeling? I would say, very lonely. How would you sum up the 
position of the rest of the black army? I would say, distant spectators
.
** Hints section, 6 hints
.
** Hint 1, to find the key move
.
Surely, you are not going for the obvious material grab?
.
** Hint 2, to find the key move
.
The queens oppose each other, so white needs a plan not involving the white 
queen
.
** Hint 3, to find the key move
.
That means, it is up to the rooks to find a mate, and what is the usual double 
rook mating pattern?
.
** Hint 4, to find the key move
.
If the mating pattern is still escaping you, turn your thinking by 90 degrees
. 
** hint 5, to find the key move
.
From the European perspective, Columbus discovered America. What can a rook 
discover here?
.
** 6th and final hint, to find the key move
.
Check what you discovered from hint 5
.
** Proposed solution to WAC050
.
Not surprisingly, with a white queen and rook so close to the black king, a 
knock-out blow lands. So, 1. Rxb6+, and there are only 2 legal replies. If 1. 
... Ka7, the heavy piece mating net is closed with, 2. Qb7+ mate. If instead, 
1. ... Qxc6, the black queen is deflected. Now the previous white rook x-ray 
attack, through the black queen shows it's power with, 2. Rxa2+. Black can 
postpone mate for a move with, 2. Qa4, but 3. Rxa4+ is mate. Notice that the 
more usual pattern, for 2 rooks to give mate, that is one rook restricting on 
the 7th rank, and the other delivering mate on the 8th rank, is not the case 
here. A 90 degrees rotation in thinking was needed to envisage the pattern, of 
the restricting rook placed on a knight's file, and the check-mating rook 
capturing while moving to a rook's file. Perhaps the early middle game, or 
endgame strategy for rooks, can lull one into thinking that rooks are going to 
move up and down the files to be effective
.
** Condensed proposed solution
.
1. Rxb6+ Qxc6 2. Rxa2+ Qa4 3. Rxa4+ mate
. 
** Other tactical variations considered, and rejected 
.
Ther are 5 other attempts for white to analyse and reject
.
Attempt 1. White has a possible forced mate, if black is not alert, with, 1. 
Rxg7+ Qxc6 2. Rxa2+, and here black must think carefully. The correct reply is, 
the rather counter-intuitive, 2. Qa4, it is vital the d5 pawn is not allowed to 
get to c6, where it sets up a mating net for the 2 white rooks. White has 3. 
Rxa4+ Kb8. Now white must choose, there are 2 rook moves onto the a7 square. 
Choice 1 is examined here, and choice 2 is examined in attempt 2. So, 4. raa7, 
keeping the option of a draw is prudent. Black can trade fxg3+, and win the d3 
and d5 pawns, white has little winning prospects, and every chance to lose.
Now to the line where black falls into a mating net. So, 1. Rxg7+ Qxc6 2. Rxa2+ 
Kb8 3. cxd6, and a point of support on the 7th rank for a rook on b7 is 
created. The unstoppable threat is, rb7+, and after Kc8, Ra8+ will be mate. It 
is worth examining this pattern carefully, noting how the 6th rank pawn 
supports one rook to give check, and forces the king sideways, permitting the 
other rook access to the 8th rank. Black has many moves here, none of which 
disrupt the mating pattern. If 3. ... Kc8 4. Ra8+ is mate. If 3. ... Rc8 4. 
Rb7+ is mate. If 3. fxg3+ 4. Kg1, keeping out of the way,and similarly if 3. 
... Ng4+ 4. Kg1, and black runs out of ideas, in both cases and the mate occurs 
again
.
Attempt 2. Now for that 4th move Ra7 alternative, noted in attempt 1. After, 1. 
Rxg7+ Qxc6 2. Rxa2+ Qa4 3. Rxa4+ Kb8, and now white sets up a mating net, which 
can only be avoided by black losing a rook. So, 4. Rga7, threatening Ra8+ and 
then R2a7+, and the d5 pawn guards the c6 flight square. The best black has is 
4. ... fxg3+ 5. Kg2, note not 5. Kxg3 Rg8+, disrupting the plan of winning a 
rook. So now black destroys the mate net with, 5. ... Nxd5. White wins the rook 
with, 6. Ra8+ Kc7 7. Rxf8, black should now play, 8. ... Bxd3, but after, 9. 
Kxg3 white should go on to win. It will be a long slog, but good technique 
should prevail, White should capture the black h-pawn as quickly as possible, 
centralise the king, and force one of the black minor pieces to guard against 
the advancement of the white h-pawn. Black's problems are, that the 2 queenside 
pawns will not offer protection to whichever minor piece is guarding that 
advance, white will just keep attacking the minor pieces with king and rooks, 
and sooner or later, the guarding black piece will be forced away, and the 
white h-pawn will soon cost a whole piece
.
Attempt 3. White can win the black queen and a pawn for 2 rooks, but the 
resulting ending is unclear. With such a powerful position, white should only 
consider giving up 2 rooks for the queen, if there is absolutely nothing else 
available. Black will have to cope with a passed d-pawn, and the black pieces 
will be vulnerable to the white queen. The line goes, 1. Rxc2 Rxc2+ 2. Qxc2 
Kxb7 3. Qc6+ Ka6, and the d6 pawn now falls. After 4. Qxd6 fxg3+ 5. Kxg3, black 
must organise the pieces to stop the advance of the white d-pawn, while 
managing not to lose all the kingside pawns, while white will always have to 
take care not to allow the black b-pawn to get too far up the board. White 
should have more than enough resources to draw, but perhaps not enough to force 
a win, black probably has the more difficult game
.
Attempt 4. There are 6 other discovered check moves for the b7 rook. If 1. Rb8+ 
Kxb8, and the best white can do is, 2. Rxc2 Rxc2+ 3. Qxc2 Rc8, and it is worse 
than the above ending. If 1. Ra7+ Kxa7, and sadly white can not play 2. Re7+ 
since that rook is pinned to the king. So, yet again white mut take the black 
queen for another worse example of the ending, in attempt 3 above
. 
Attempt 5. Another plausible discovery move is, 1. Rf7+, attacking the f8 rook. 
Black must take 1. ... Qxc6, and now there are 2 black rooks attacked. So, 2. 
Rxa2+ Kb8 3. Rxf8+, and now black cleverly plays 3. ... Qe8, and white the 
black queen is costing white a rook. After 4. Rxe8+ Nxe8, black seems to have 
better prospects in the ending
.
** Alarm bells
. 
1. The discovered check is a very powerful tactical tool. Allowing your 
opponent to set one up on you, may be placing your head in a noose. Planning to 
avoid being caught in one, may be the sensible approach
.
2. Chess is like boxing. Sometimes you punch, and sometimes you duck. Black 
seems to have decided to not play defensive moves leading up to the problem 
position. If you want to play similarly, practice calculating tactics in 
complex games
.
3. Be aware of your tactical ability, play to your limitations. I once heard a 
player of F.M. strength, after having sacrificed needlessly and lost, explain 
to his opponent: I thought I was Tal reincarnate"
.
Paul Benson.

-----Original Message-----
From: R Dinger - Email Address: rrdinger@xxxxxxxxxx
Sent On: 03/01/2011 16:46
Sent To: chess - Email Address: blind-chess@xxxxxxxxxxxxx
Subject: [blind-chess] Problem WAC050

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 WAC050

White to move

FEN Problem Setup:
k4r2/
1R4pb/
1pQp1n1p/
3P4/
5p1P/
3P2P1/
r1q1R2K/
8
 w - - 0 1

Short Algebraic Problem Setup:
White: Kh2, Qc6, Rb7, Re2, Pd3, Pd5, Pg3, Ph4
Black: Ka8, Qc2, Ra2, Rf8, Bh7, Nf6, Pb6, Pd6, Pf4, Pg7, Ph6 

Other related posts: