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|Aug-05-09|| ||JG27Pyth: This one gave me fits for a while as I kept trying to find a way to make something happen directly against the King, using f7... when I investigated the possibilities around both skewering the queen to the king and forking queen and rook, the combination 'popped out' for me. I didn't think there was much in the way of defensive variations to contend with, and that surmise appears to have been correct.|
|Aug-05-09|| ||cyclon: An excellent puzzle! 10.Bxb6 seems so meaningless and harmless at the first glance.|
|Aug-05-09|| ||kevin86: I saw this one-if white could divert the pawn away from the c-file,he could pin the queen after ♗b5. The exchange and then fork on the adjacent file allow for the theme/dream to come true.|
|Aug-05-09|| ||Weadley: I do not get why the queen on move 11 would not just move back and cover the rook. It end up only being a poor trade for black not a queen skewer.|
|Aug-05-09|| ||al wazir: After 11...Qd8 12. Nxa8 Qxa8, black is down an exchange. While I wouldn't like to play down an exchange against Bogoliubov in his prime, I wouldn't have resigned.|
|Aug-05-09|| ||Weadley: Exaclty!!! This is not a win for white therefore it should not be a wednesday puzzle! I do not see winning a favorable exchange as opposed to outright winning a piece a decent puzzle at all for a medium puzzle. I am not saying I would not like to have that happen in one of my games but it certainly does not mean anyone is going to win or not.|
|Aug-05-09|| ||desiobu: I missed that the bishop has to take first so that the knight fork makes the threat of pinning the queen more problematic for black|
|Aug-05-09|| ||zanshin: <Patriot: Yeah I can see a lot of players making this mistake.>|
I would be one of them. I would prefer Qd7 to keep my back rank clear for castling and reason that Bb5+ would be met by c6.
|Aug-05-09|| ||TheaN: Wednesday 5 August 2009
Candidates: Nd5, Qxb6, Nxb6..., <[Bxb6]>
In this seemingly normal position White is clearly up in development in exchange for the pawn. It's just about finding the right combination: looking for a long time at 10.Nxb6 axb6 11.Bxb6, White may win his pawn back but it's nothing more. If we turn that around, as usual, we get the solution:
<10.Bxb6> ignoring just loses a Bishop outright. Cannot really find a Black move that may stall the threats and still attack the Bishop without it being able to move. Whatever Black threatens, Be3 will just gain the piece for at most two pawns.
<10....axb6> obviously, but still a bit tricky, after 10....cxb6 White wins with 11.Bb5 , pinning the Queen on the King. If White tries that now, 11....c6 holds easily. That line of thinking let to the, now working, sham sac:
<11.Nxb6 > 11....cxb6 leads to the same Bb5, and any Queen move with the Knight as last piece on b6 leads to Nxa8, being up a Rook temporarily but probably a winning exchange in the long run. Time to check.
|Aug-05-09|| ||doubledrooks: 10. Bxb6 axb6 11. Nxb6 cxb6 12. Bb5 pins the black queen and wins. |
Just goes to show: always be careful when you put your king and queen on the same diagonal/rank/file.
|Aug-05-09|| ||Patriot: <Weadley: Exaclty!!! This is not a win for white therefore it should not be a wednesday puzzle! I do not see winning a favorable exchange as opposed to outright winning a piece a decent puzzle at all for a medium puzzle. I am not saying I would not like to have that happen in one of my games but it certainly does not mean anyone is going to win or not.>|
In my book, winning the exchange is usually a technical win (depending on the position). Larry Kaufman researched and found that the exchange is worth about 1.75 pawns on average. And I think GM's agree that you need a 1 pawn advantage to be considered winning.
Would you think a puzzle where winning a pawn is the solution, a decent puzzle? Just curious...Thanks!
|Aug-05-09|| ||kingfu: I think the point of today's puzzle is to show that just because a piece is protected by 2! pawns it can still be part of a great combination. Bogo certainly put a hurt on Black, but I would not resign just being down the exchange. Maybe black was just totally disgusted with his play and had to go out for a vodka or 2 or 12.|
|Aug-05-09|| ||Jimfromprovidence: <LIFE Master AJ> <johnlspouge> <patzer2>|
This puzzle reminded me of an April Wednesday puzzle from earlier this year, below, where
proper move order was necessary for success. So I had my guard up for this one.
A Burjan vs A Kornelia, 1992
Move 30, black to play.
|Aug-05-09|| ||patzer2: <TheaN> <If White tries that now> (after 10. Bxb6 axb6 11. Bb5+) <, 11....c6 holds easily> Maybe not so easily. After 10. Bxb6 axb6 11. Bb5 c6? 12. Nb5! Rc8 13. f3 e5 14. Rd1 Qe7 15. Nd6+ White is winning easily. Instead the clever 11...0-0-0! = to given by <Jimfromprovidence> is probably Black's best practical chance here.|
|Aug-05-09|| ||Patriot: <patzer2: <TheaN> <If White tries that now> (after 10. Bxb6 axb6 11. Bb5+) <, 11....c6 holds easily> Maybe not so easily. After 10. Bxb6 axb6 11. Bb5 c6? 12. Nb5! Rc8 13. f3 e5 14. Rd1 Qe7 15. Nd6+ White is winning easily. Instead the clever 11...0-0-0! = to given by <Jimfromprovidence> is probably Black's best practical chance here.>|
Isn't 10.Bxb6 axb6 11.Bb5 illegal since a knight is blocking on c4?
|Aug-05-09|| ||David2009: Wednesday's puzzle Bogoljubov vs Grekov, 1914 White to play 10? Medium/Easy.
Black's K is too well defended for mate threats to work. After trying other things, I hit
on 10 Bxb6 axb6 11 Nxb6! winning material (forking R and Q) since 11..cxb6 allows Bb5 winning the Queen.|
My problem is, I spot these combinations as puzzles, I miss them over the board in rapid-play
chess (www.freechess.org, my handle is DavidMMIX). With the clock ticking away I am impelled to make
the first reasonable-looking move I can see.
Time to check.
|Aug-05-09|| ||LIFE Master AJ: <patzer2> Your comments are always highly informative.|
|Aug-05-09|| ||wals: The following may be of help to those wanting help
[White "Efim Bogoljubov"]
[Annotator "Rybka 3 1-cpu (30m)"]
D02: 1 d4 d5 2 ♘f3 sidelines, including 2...♘f6 3 g3 and 2...♘f6 3 ♗f4 1. d4
d5 2. Nf3 (2. c4 e6 $14) 2... Bg4 (2... Nf6 3. c4 $14) 3. Ne5 (3. c4 Nc6 )
3... Bh5 (3... Be6 4. c4 ) 4. c4 (4. Qd3 Qc8 ) 4... dxc4 (4... f6 5. Nf3
dxc4 6. e3 ) 5. Nc3 (5. g4 f6 6. Bg2 c6 7. Nxc6 Nxc6 8. gxh5 Qd7 ) 5...
Nd7 6. Nxc4 Nb6 (6... c6 7. a4 ) 7. Qb3 (7. Na5 Rb8 ) 7... Qxd4 (7... Nf6
8. e4 ) 8. e4 Nf6 (8... Qd7 9. Be3 Rd8 10. f3 (10. Bxb6 axb6 (
10... cxb6 11. Nd5 Rc8 12. Ne5 ) 11. f3 Nf6 )) 9. Be3 White
threatens to win material: ♗e3xd4 Qd7 another bit of territory lost (9...
Qd8 ) 10. Bxb6 (10. Nxb6 axb6 11. e5 Ng4 ) 10... axb6 (10... e6
11. Be3 c6 12. f3 ) 11. Nxb6 the knockout punch (11. Nxb6 Qd8 12. e5
cxb6 13. exf6 ) 1-0
|Aug-05-09|| ||johnlspouge: < <Jimfromprovidence> wrote: [snip] This puzzle reminded me of an April Wednesday puzzle from earlier this year, below, where proper move order was necessary for success. So I had my guard up for this one. >|
Hi, <Jimfromprovidence>. Thanks for reminding me of one of the more interesting puzzles we have had. I have no idea, however, how the previous puzzle alerted you to be careful here...
|Aug-05-09|| ||OBIT: I can't remember Bogoljubov's opponent (maybe somebody here remembers the game), but I recall once seeing a game where Bogoljubov's opponent blundered a piece in the opening with no real compensation, and Bogoljubov then went on the misplay the position and lost.
Given that game, Bogoljubov's opponent in this one, who is only down an exchange with best play, may have resigned too soon.|
|Aug-05-09|| ||Jimfromprovidence: <johnlspouge> <Hi, <Jimfromprovidence>. Thanks for reminding me of one of the more interesting puzzles we have had. I have no idea, however, how the previous puzzle alerted you to be careful here...>|
Hello from the left coast. It's simple. <dzechiel> got the move order wrong from that one. It stuck with me.
|Aug-05-09|| ||WhiteRook48: did not get it|
|Aug-05-09|| ||patzer2: <Patriot> You're right, that line is in error and impossible. I was trying to communicate that after 10. Nxb6 axb6 11. Bxb6, the try 11...c6 fails to 12. Nb5! Rc8 13. f3 e5 14. Rd1 Qe7 15. Nd6+ .|
However, that line seems to have nothing to do with what <TheaN> was trying to communicate, which appears to be that following 10. Bxb6 cxb6, the followup 11. Nxb6 axb6 12. Bb5! pins and wins.
P.S. My apologies for misunderstanding <TheaN>. A.J., I try, but ever so often when I get confused, as in this case noted by <Patriot>, my posts are not always so informative.
|Aug-06-09|| ||LIFE Master AJ: <WhiteRook48> I must admit, if you are not familiar with the basic idea, the tactic can be hard to spot! (I once found an idea similar to this against a good player in a tournament. |
"No big deal," you say? Well, maybe. But back then, I was rated about 1100, and my opponent was rated like 1900. (In those days, the late 1960's or early 1970's, 1900s almost NEVER lost to an 1100!)
|Aug-06-09|| ||LIFE Master AJ: <patzer2> EVERYONE makes mistakes, dude! Don't sweat it. (I still like you ... a smiley face here.)|
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