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< Earlier Kibitzing · PAGE 3 OF 3 ·
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| Apr-25-08 |
| Petrosianic: A pseudo sacrifice would be one where the future gain (or recovery at least) is calculable. A real sacrifice is one where the future gain is speculative. If I sacrifice a piece, but can show concrete variations proving that I can get it back in 5 moves, then that's a pseudo sacrifice. Or, a better example. The King's Gambit is a real gambit. The Queen's Gambit isn't. White can recover the pawn immediately with 3. Qa4+ if he really wants to. |
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Apr-25-08
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| johnlspouge: <<NitramBackwards> wrote: ha ha ha, guess I'll come back Monday.> Welcome, <NitramBackwards>. Your username, icon, and comment all display the kind of perverse humor I revel in - no chess required! I look forward to "seeing" you again on Monday :) |
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Apr-25-08
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| johnlspouge: <<zooter> wrote: <benveniste: <zooter>, on your line, I think black can hold things together with 27. ... Kf8>> Mercifully, I did not spend much time on false leads today. Your line was tempting, <zooter>, and the only false lead I had to backtrack on today. Because my posts are long enough, I do not write everything down. I do, however, appreciate seeing annotation for the line, <benveniste>, so thanks. |
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| Apr-25-08 |
| mikhs: Petrosianic: what if you didn't calculate deep enough and loose all that advantage on the 6th move? I think that there are just sacrifices that work and ones that don't. Based on your definition the distinction between a "pseudo" and a "real" sacrifice depends only on ability to calculate deep enough. So the higher the level of play the more likely sacrifices to be "pseudo" ?? |
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| Apr-25-08 |
| Petrosianic: <Based on your definition the distinction between a "pseudo" and a "real" sacrifice depends only on ability to calculate deep enough.> Well, it's not really my definition, that's just what I've always understood the term "pseudo-sacrifice" to mean. It's possible that it's not really a very good term, for the reasons you give, or possible that I'm not defining it quite correctly. |
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| Apr-25-08 |
| TheCap: <eaglewing>, <nuwanda>, : <TheCap 24. Nxb7 Rxc3 25. Rxc3 Rb8:> You miss 26. Nc6 Qxb7 27.Nxb8 losing the exchange. Yes, of course. I overlooked that. Thx.
Apr-25-08 nuwanda: Hi <TheCap>, after 24.Nxb7 Rxc3 25.Rxc3 Rb8
i think the simlpe 26.Nc6 wins...
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Apr-25-08
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| kevin86: Great combination!! The very unusual fork of knights on the 26th move and the fake sac on the next move are worth the price of admission. That kind of fireworks deserves a great OOOOOOOOOOOOOOHHHHHH! from the crowd. |
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Apr-25-08
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| YouRang: Well, at least I can say that I honestly considered 24.Nxb7, but you gotta be pretty confident in your long range calculation skills to follow through with it. I wasn't. :-p |
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Apr-25-08
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| YouRang: FWIW, if I had this position, I'd probably be content to trade down: 24.Nd7 (cutting off Q defense of Rc7) Rxc3 25.Rxc3 Rxc3 26.bxc3 Nd6 (guarding Pb7) 27.Nc5 And material is about even, but my knights are better than black's. He can't get his knight out of the a8 hole without losing Pb7. Nothing fancy. Just squeezing out a little advantage. |
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| Apr-25-08 |
| Blitzkrieger: Can anyone plz explain what is wrong for black if it just plays 24. ... Rxb3 25. Rxb3 Rxb3 26. bc ?
Isn't it an objectively better choice than accepting the sacrifice that leads to a faster finish. |
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Apr-25-08
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| johnlspouge: <<Blitzkrieger> wrote: Can anyone plz explain what is wrong for black if it just plays 24. ... Rxb3 25. Rxb3 Rxb3 26. bc ? Isn't it an objectively better choice than accepting the sacrifice that leads to a faster finish.> I do not have access to computer evaluation right now, but your "objective" assessment is probably correct. In this line, Black is down a P with his back against the wall, with no imbalance to work with. This line is like kneeling, baring your chest, and waiting for White to put the knife in - slowly. A computer (or an objective assessment) does not factor in the suffering a human must endure in a position <both> hopeless <and> lifeless. |
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Apr-25-08
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| YouRang: <Blitzkrieger: Can anyone plz explain what is wrong for black if it just plays 24. ... Rxb3 25. Rxb3 Rxb3 26. bc ? Isn't it an objectively better choice than accepting the sacrifice that leads to a faster finish.> Firstly, if black turns down the queen sac, white would say to all the onlookers: "Hey everyone! Look who's too CHICKEN to take my queen! HAW HAW!". Then, after trading off the rooks, white would grind him down to powder, making black's queen-sac refusal appear even more humiliating. It's better to get beat in a daring & flashy battle than be made to look like a sissy. :-) |
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Apr-25-08
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| johnlspouge: <<YouRang> wrote: [snip] It's better to get beat in a daring & flashy battle than be made to look like a sissy. :-)> Yeah, a computer doesn't lower its evaluation function for looking like a sissy. You have a pleasant writing style, <YouRang>. Your answer is right to the point. |
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| Apr-25-08 |
| Akuni: Why not 37. Ng6+ Kh5 38. Nxe7 |
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| Apr-25-08 |
| cyanfish: <Akuni> 37. Ng6+ is perfectly fine. Both it and 37. Nf3+ lead to an easy win, though in fact (according to my human analysis; I may have missed something) Ng6+ mates a move quicker. The mates are as follows:
37. Nf3+ Kh5 38. Rhg8 Qg7 <only way to delay mate; threat is Rh3+ followed by Rxh4> 39. R8xg7 <which rook doesn't matter, as long as it moves back>
Kh6 40. Rg8 followed by 41. Rh3#
37. Ng6+ Kh5 38. Nxe7 Kh6 39. Ng8+ Kh5 40. Rxh7#
The win is really just technique. |
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Apr-25-08
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| JG27Pyth: <JohnLSpouge:Black is down a P with his back against the wall, with no imbalance to work with. This line is like kneeling, baring your chest, and waiting for White to put the knife in - slowly.> Yes. But it is better than the text. I kept looking for another solution because I saw this answer to the N sac and thought... jeez, winning a pawn without compensation in a middle game... that's nice, but no way it's a puzzle solution. I'm curious to see what the computer eval is... Black would be playing for draw from there, but I don't think he just resigns. |
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Apr-25-08
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| JG27Pyth: Addendum: Actually, looking at it after the exchanges... I don't think I need the computer eval... black is terrible! Material-wise sure he's only down a pawn for the moment, but the Knights are terrible, the back rank is weak, the Queen is going to penetrate...I take it all back...John you are right -- except I'm not sure the end comes all that slowly ... |
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Apr-25-08
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| YouRang: <johnlspouge><You have a pleasant writing style, <YouRang>. Your answer is right to the point.> Why, thank you. :-)
Funny that we both gave <Blitzkrieger> essentially the same answer. Yours slightly more chess oriented. ;-) |
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Apr-25-08
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| whiteshark: Didn't get it within a minute. :( |
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Apr-25-08
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| johnlspouge: <<JG27Pyth> wrote: I kept looking for another solution because I saw this answer to the N sac and thought... jeez, winning a pawn without compensation in a middle game... that's nice, but no way it's a puzzle solution.> <JG27Pyth>, you sly old dog you, while the rest of us have been spending our time discussing the best way to lose, you've been quietly improving, haven't you? Now, c'mon, 'fess up... <I'm curious to see what the computer eval is... Black would be playing for draw from there, but I don't think he just resigns.> My wife is out of town with my mother today, so I can let the chess analysis run for a whole 17 plies, instead of the usual 15. Whoopie! Toga II 1.3.1 evaluates the puzzle position as follows, with my usual conventions: [ply 17/50, time 03:10, value +1.93]
23…<Ne8> 24.Nxb7 Nf6 25.Rxc7 Rxc7 26.Nc5 Qf8 27.f3 Qc8 28.Qd3 Ra7 29.Rc3 h6 30.Kg2 Kh7 31.Kh1 Nc7 32.Rc1 Kh8 33.Ng6+ Kh7 34.Rg1 No surprise: Toga refuses the 24.Nxb7 sacrifice. There was one point I needed to clear up in the game line, however. I gave a line that followed the game line up to 27...<Qe7> and then diverged as follows: 27...<Qa7> 28.Nc6 Q moves 29.Rxa8 leaving White with 2Rs+P vs. Q, which seemed better for Black than the game line. In fact, White has a nice improvement: 27...<Qa7> 28.Rxe8+ Kxe8 29.Rc8+ Ke7 30.Nc6+ K moves 31.Nxa7 leaving White a whole R up, which explains why Lisitsin chose 27...Qe7 over 27...Qa7. I was witholding judgment on some of your comments, <JG27Pyth>, until I could resolve this line. With this line in hand, I agree that Black is definitely best refusing the sacrifice Nxb7. <<JG27Pyth> wrote: I take it all back...John you are right -- except I'm not sure the end comes all that slowly ...> We should avoid debates, <JG27Pyth>: we switch sides so fast, nobody can see our positions for the blur. |
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| Apr-25-08 |
| 234: Thursday puzzle <32. ?> Apr-24-08 Ponomariov vs E Tomashevsky, 2007 |
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Apr-25-08
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| wals: Static Evaluation: Who iin front, by how much, and why?
White's knights are more active than black's.
Material is even. White has an isolated pawn on a5.
The c-file is stacked up with batteries but white would appear to have the edge, as it stands.
White has the advantage of the move.
Dynamic EValuation: Opening the c-file by moving Nc5-a4 would result in what?
Rc3, attacked twice, protected, four times. Odds are good, if black attacks.What if say,Qd6,
then Rc7, is attacked twice, and protected, four times.
Now if we divert Rc7, it gives the two white c-file rooks, open slather at the back rank. Abstract Assessment: If Ne5 goes to d7 it would need to be taken because of a possible move b6. candidate move: Ne5-d7
24.Ne-d7 ...Rxd7 25.Nxd7 ...Qxd7 26.RxRc8 ...Qxc8 Rxc8 PM= .
No way, Jose., too classy for me
Fritz differs from the given text
Mark Taimanov - Georgy Lisitsin, Leningrad 1949
Analysis by Fritz 11:
1.  (2.44): 24.Nc5xb7 Rc7xc3 25.Rc1xc3 Rc8xc3 26.b2xc3 Qe7-c7 27.Kf1-g2 h7-h6 28.Nb7-c5 Qc7-c8 29.Ne5-d7 Na8-c7 30.Qb3-b6 Qc8-d8 31.Nd7-b8 Qd8-h4 32.h2-h3 Qh4-e7 33.Nb8xa6 2. (1.82): 24.e3-e4 Ne8-f6 25.e4xf5 e6xf5 26.Nc5-d7 Rc7xc3 27.Rc1xc3 Rc8xc3 28.b2xc3 Qe7-d6 29.Qb3xb7 Na8-c7 30.Nd7-c5 g7-g6 31.Kf1-g2 Nf6-e8 32.h2-h3 Ne8-f6 33.Qb7-b6 Nf6-e8 34.Kg2-g3 Kg8-g7 (, 26.04.2008)
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| Apr-25-08 |
| DarthStapler: I got the first move, but regarding earlier in the game, why did white let black play Bxf4? Doesn't that ruin his kingside pawn structure? Or did he think the f4 pawn's central influence was worth it? |
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| Apr-26-08 |
| capin: 24. Nxb7 h6 25. Rxc7 Rxc7 26. Nc5 Qd8 27. Rc2 Qc8 28. Ned3 Nd6 29. Nb4 Qe8 30. Nbxa6 Ra7 31. Qb8 Qxb8 32. Nxb8 Rxa5 33. Nxe6 Ra1+ 34. Kg2 Ra2 35. Nc6 +6.34 |
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| Aug-02-09 |
| WhiteRook48: 39 R8g5+ Kh6 40 Rh3# |
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