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|Aug-15-06|| ||islero: Wow 17...c4! just wins! 19.Bxc4 wasn't better here: 19 ... Rc8 the threat of b6-b5 forces 20 Qd3 (20 Qb3 b5 21 Bd3 Bd5 ) 20 ... Be4 21 Qb3 b5 22 Bd3 Bd5 |
The end is 21 Qa4 b5 22 Qxa6 Ra8 23 Qxb5 Ra5 what terrible luck! :-)
|Jul-21-07|| ||wouldpusher: Nice Queen trap. I was looking into 19. Bxc4 and didn't see everything.|
|Jul-21-07|| ||Gregor Samsa Mendel: I guess white's last mistake was the "natural" 17 Rad1, which denies the queen a vital flight square. So, what should white have played on move 17?|
|Jul-21-07|| ||dzechiel: Very difficult. Black to move. Material even. The position looks kinda even (but I would rather have the white knight on f3). All of the white pieces seem safe from capture, so black must either muster up an assault on the king, or find some way to take advantage of the white queen on the half open c-file.|
Let's consider some candidate moves:
After a couple of minutes of considering the position, I would like to examine a line that uses two of the candidate moves:
17...c4 (very forcing and it keeps the a1-h8 diagonal closed) 18 bxc4 Rc8
The threat is now 19...dxc4 20 Bxc4 b4 getting the bishop for a couple of pawns. After 18...Rc8 white cannot play 19 cxd5 because of the pin on the queen. Pushing 19 c5 doesn't seem that much better after 19...bxc5 with the threat of 20...c4 or 20...cxd4 with a discovered attack on the queen.
The problem as I see it here is that white has a lot of moves at his disposal that don't seem to lose immediately (such as 19 Qb1 or Qd2) and I don't see a winning combo for black. Let's look closer.
OK, I have a confession to make. I set this position up on my chess table and took a look (I used to play a LOT of correspondence chess). The line seems to go:
17...c4 18 bxc4 dxc4. Now white must capture the pawn or lose the bishop. Let's look at both tries:
- 19 Bxc4 Rc8, now, to avoid 20...b5 winning the bishop, white must move the queen to either b3 or d3. 20 Qb3 b5 21 Bd3 Bd5 and the queen has nowhere to go! Or, 20 Qd3 Be4 21 Qb3 b5 22 Bd3 Bd5 and we have the position from the first line!
- 19 Qxc4 Rc8 20 Qa4 b5 21 Qb3 Bd5 and once again we reach the same winning position.
I gotta believe this is it (but I don't think I would have seen it just staring at the diagram). Time to check.
|Jul-21-07|| ||MostlyAverageJoe: BOGUS PUZZLE.
Just as the others, I figured out that
17. ... c4 18. bxc4 dxc4
is the best that the black can do, and expected white to take with the bishop and the black to pin it.
19. Bxc4 Rc8
This looks reasonably good, but after setting up the position and shuffling pieces in a Java applet, I did not see this as winning by force:
click for larger view
Fine, so the bishop is pinned, but the white can try to align his Q and B on the long diagonal and deflect the black bishop to win the knight, which cannot run away because of a mating threat. At this point I gave up thinking and plugged it into Hiarcs, which confirms that it should work:
20. d5 b5 21. d6
click for larger view
Now if RxB, then pxB, Qxp, and white has his bishop back, with Q free to go. Therefore:
21 ... Bxd6 22. Qc3 Rxc4 23. Qxf6
click for larger view
Black to move, and he better exchange queens. After plugging the above into Hiarcs, I get -0.54 valuation. Big deal.
|Jul-21-07|| ||chessgames.com: Kosma rejected 19.Bxc4 almost certainly because after 19...Rc8 attempts to break the pin lose:|
A) 20.Qb3 b5 21.Bd3 Bd5!
B) 20.Qd3 Be4 21.Qb3 b5 22.Bd3 Bd5!
When we ran it through some computers we discovered that White has some resources to stave off the attack. Our private notes to this game read as follows: <Refuted with 19.Bxc4! Rc8 20.Nf4!! b5 21.Ne6!! => We decided to use it as a puzzle anyhow.
|Jul-21-07|| ||MostlyAverageJoe: <chessgames.com: <Refuted with 19.Bxc4! Rc8 20.Nf4!! b5 21.Nd6!! =>> I think you mean 21.Ne6; d6 is not reachable from f4. Indeed, it is a very cute position:|
click for larger view
where the white ♘ is untouchable (if fxe6, then Bxe6+ and white will end up with slight advantage). It evaluates at -1.42 after 22 plies, leading to this exchange:
21 ... Rxc4 22. Qxc4 bxc4 23. Nxd8 Rxd8
so the black has more advantage here than after 20.d5!!! (it got to have one more ! than your 20.Nf4 :-)
BTW, update on my last post: the final position shown there evaluates at -0.56, 24-plies deep. I re-verified the entire line, and it definitely seems to be the best for white. During verification, another variant has been identified, branching thus: 21.Qd2 (instead of 21.d6 I posted), with almost the same valuation (0.03 worse).
Maybe RandomVisitor could unleash Rybka on the puzzle ...
<We decided to use it as a puzzle anyhow.> I have no problems, with that. The next best move for the black seems to be 17...Qc7, with slight advantage for white.
And finding a better response than what was played in the actual game is quite satisfactory, even if I had to use silicon monsters to confirm it :-)
|Jul-21-07|| ||bogo78: The position puzzles me to the limit of bewilderment. Ok, I admit I started saturday with a few beers but still... Black has no pieces that are in place for an immediate attack, one entombed bishop. If I were to play this I would not look for a combination even if it were a correspondence game. A nice positional move is what I would try. Hmm, I guess there is a reason I ain't called Korchinoi. If my bishop would be on d6 then I would start calculating Bxh2. But well it is not. So I am in a moral dilemma here. I guess I' ll cheat and look now or else I wont be able to sleep. I am very sorry for the incoherent message, I promise I wont drink and drive (pardon, study a puzzle) ever again!|
|Jul-21-07|| ||bakuazer: i got this all correct, except after
17..... 21...b5 22.Qxa6 Ra8 23. Qxb5
my move was 23...Rb8 and white looses the b2 bishop, i think this is good enough.
it is a bit funny though, bc when i started thinking on the puzzle, of course, 17..c4 was irresistable, but for a long time I tried to find an attack on the king only to relaize that instead the queen is trapped. but
at the very end, i missed the queen trap winning the bishop instead, which I still believe is a win for black (black is still on the attack)though not very clear.
|Jul-21-07|| ||HelaNubo: <chessgames.com: Our private notes to this game read as follows: <Refuted with 19.Bxc4! Rc8 20.Nf4!! b5 21.Ne6!! => We decided to use it as a puzzle anyhow>
I do not understand how White can draw after the obvious 21...Qe8. It seems like a simple win for Black.|
|Jul-21-07|| ||Aspirador: Not such a bogus puzzle at all. Both 20.Nf4 and 20.d5 end up with a clearly better position for black.|
Even the line 20.d5 b5 21.d6 Bxd6 22.Qc3 Rxc4 23.Qxf6 Qxf6 24.Bxf6 is, imho, a win for black with the pair of bishops and a queenside majority.
|Jul-21-07|| ||willyfly: material is dead even and there's nothing that stands out to me in the positions - started a new job last night - very tired - my mind's not into this - the only move that stands out to me is 17...c4 - let's look|
haha - it was 17...c4
But I had no brilliant plan - I would have made that move just to get something going
|Jul-21-07|| ||jon01: Yeah, my only thought was 17...c4 but I didn't see that it captures white's queen. I was more thinking of getting black bishops to strong diagonals h1-a8 and h2-b8.|
|Jul-21-07|| ||Marmot PFL: White could still play on 21...b5 22.Qxa6 Ra8 23.Qxb5 Ra5 24.a4 with a rook and 3 pawns for the queen. Bad of course but black has no fast way to win.|
|Jul-21-07|| ||skemup: My first saturday's puzzle which i solved. I focused on c4 move becouse first and second move of white were forced.|
|Jul-21-07|| ||4i4mitko: well c4 was obvious but the rest was not
actually i've missed Qxc4:)))
|Jul-21-07|| ||realbrob: I thought 17..c4 was the best move for Black because it set up a very interesting situation, opening the c file for the Black rook (which could also result in a pinned white bishop), and maybe it created also some attacking possibilities against the white king (opening the black LSB diagonal). I would be a liar though if I said I saw 17..c4 was completely winning.|
|Jul-21-07|| ||al wazir: What would black have played if the game had continued? The best I can see is 21...b5 22. Qxa6 Ra8 23. Qxb5 Ra5, and now the ♕ is well and truly trapped. But after 24. Qxa5 Qxa5 white has ♖+♙+♙+♙ vs. ♕.|
Granted, the ♙ on a2 is a goner, but after 25. Nc3 Bxa2? 26. Ra1, black's ♗ is pinned and the shoe is on the other foot.
Am I missing something? Or should I cue up my theme song: "I would have played on a few more moves."
As usual, I wouldn't have seen 17...c4 if <CG> hadn't posed this position as a problem -- and certainly not OTB. I would love to know what went through Korchnoi's mind before he moved. Did he think he would win a piece? Did he only expect to make white struggle? Did he perhaps analyze just one of the lines and think it was winning? (He surely didn't do all the analysis given here.) Did he make the move on general principles, without doing any of the analysis?
|Jul-21-07|| ||tdubb43: Aesthetically, this is a horrid puzzle. Absolutely horrid.|
|Jul-21-07|| ||patzer2: The surprise deflection 17. c4!! solves today's puzzle and traps the queen after the unfinished move sequence 21...b5! 22 Qxa6 Ra8 23 Qxb5 Ra5 .|
|Jul-21-07|| ||kevin86: This puzzle was too rich for my blood. I was thinking about a kingside attack by ♘g4 followed by ♗d6 and ♕h4-I had no idea on a queen trap.|
|Jul-21-07|| ||keypusher: <tdubb43> Mind elaborating, Mr. Ruskin?|
|Jul-21-07|| ||newton296: its amazing, korchnoi is always finding moves that few ever think of. I imagine this quality is the key to his great carreer, or any other, for that matter, who will rise to the tops of chess.|
|Jul-21-07|| ||fm avari viraf: White position looks solid but if one sees through Korchnoi's microscope then the Queenside seems to be vulnerable & he beautfully exploited it with his superb tactical play. I still remember, when I prophesied the score 5-5 during the World Championship against Karpov when Krochnoi was 2-5 trailing. But suddenly he got his power & strength to level the score 5-5 & FIDE stopped the match for reasons unacceptable to the World & thus deprived Krochnoi of the covetous World Title which he rightly deserved. Of course, last year he won the World Senior where unfortunately I couldn't participate. Even at this age, he solid as a rock.|
|Jul-21-07|| ||patzerboy: Thumping my chest right now.
I saw this one quickly and clearly.
Would I see it in a game? Aaahhh!
Now THAT is the REAL puzzle!
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