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Jul-31-10
 | | kevin86: No clue on this one-must be above my pay grade. |
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| Jul-31-10 | | DanDylan: I'll venture to share my patzer thoughts for all you interested teachers. The position is complicated, but a few minutes examination leads me to note that if the f5-pawn were to disappear, White has 21.Be4! So, the most promising first move in my mind is 21.Ne4, after which I see three candidates for Black: 21...Qe7 22.Nxf5 exf5 23.Ng5, which I call good for White;
21...fxe4 22.Bxe4, also good for White;
21...Bxd4 22.Ng5, again ganging up on h7.
I guess I'd have played 1.Ne4; I studied the problem for 10 minutes. Now I'll check and see how badly I'd be torn up. |
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Jul-31-10
 | | thegoodanarchist: Valerga spoils a won game with 32. b4? but Lemos failed to find the refutation 32...Bf6!?  |
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| Jul-31-10 | | BOSTER: Because h7 is a weakness, and at this moment bishop on f6 is blocking move f7-f6, and in addition Qc7 unprotected I have to check moves like Re4, Ne4 and Nxf5. Main iea to put white bishop on e4.
I would play 21.Ne4 because this is more forced move . 21...fxe4 22.Bxe4 Rfc8 23.Qxh7 Kf8 24.dxe6 (threat Nf5 and Rd7).
After this there are too many lines,and none of them are forced. |
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Jul-31-10
 | | gawain: To <al wazir> who asked: How about 28...Qc6+ 29. Kf1 (29. Kg1/Kh2? Nf3+) ? [after <gawain: Also, in the game continuation, 28 Rd8 would have wrapped it up immediately. Is there any reply to this?>] Nice try. If 28 Rd8 Qc6+ White must play 29 f3! then if 29...Qxf3+ 30 Kg1 Black, surprisingly, has nothing left to try 
click for larger viewThere are still a couple of pitfalls for White if Black tries 30...Nd3 in this position but if W plays Qe3 now or after Rxe8 he'll be fine |
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Jul-31-10
 | | scormus: <DanDylan> not bad for 10 minutes work! |
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Jul-31-10
| | scormus: <gawain White must play 29 f3! > neat resource! You survived the Green Knight's axe then? |
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Jul-31-10
 | | LIFE Master AJ: I found 21.Ne4 after just a few minutes, although the game continuation would be worthy of a Sunday puzzle, IMO. |
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Jul-31-10
 | | agb2002: White has a bishop and a knight for the bishop pair. Black threatens ... Nxb2, ... Nxa3.
The bishop on f6 does not allow ... f6 if White threatens the square h7. This suggests 21.Ne4: A) 21... fxe4 22.Bxe4
A.1) 22... Rfe8 23.Qxh7+ Kf8 24.Nxe6+ Rxe6 (24... fxe6 25.Qxc7 + - [Q+2P vs B+N]) 25.dxe6 A.1.a) 25... Nxb2 26.Rxd8+ Bxd8 27.exf7 (27.e7+ is probably stronger) Qxf7 28.Qxf7+ Kxf7 29.Bxb7 + - [R+2P vs N]. A.1.b) 25... Rxd1 26.Rxd1 Bxe4 (26... Ne5 27.Rd7 Nxd7 28.Qxf7#) 27.Qxe4 fxe6 28.Qxe6 Be7 29.Rd7 Qc5 30.Rxe7 Qxe7 31.Qxc4 + - [3P]. A.1.c) 25... Bxe4 26.Rxd8+ Bxd8 27.Rxe4 + - [R+3P vs B+N] and multiple threats: 28.e7+, 28.Rxc4, 28.exf7, 28.Rg4, etc. (27... fxe6 28.Qxc7 Bxc7 29.Rxc4). A.1.d) 25... Nd6 26.Rxd6 Rxd6 (26... Bxe4 27.Rxd8+ Bxd8 28.Rxe4 + -) 27.Bxb7 Qxb7 28.e7+ Ke8 (28... Bxe7 29.Qh8#) 29.Qg8+ wins. A.2) 22... h6 23.Qxh6 Rfe8 24.Qh7+ transposes to A.1. B) 21... Bxd4 22.Ng5
B.1) 22... Rfe8 23.Qxh7+ Kf8 24.Rxd4 with the double threat 25.Rxc4 and 25.Nxe6+. B.2) 22... Bxf2+ 23.Kxf2
B.2.a) 23... Qc5+ 24.Kf1 Ne3+ 25.Rxe3 + - (25... Qxe3 26.Qxh7#). B.2.b) 23... f6 24.Nxe6 winning the exchange.
B.2.c) 23... Rfe8 24.Qxh7+ Kf8 25.Rxe6 fxe6 26.Qxc7 + -. C) 21... Qe7 22.Nxf5 exf5 23.Ng5 Bxg5 24.Rxe7 Bxe7 25.Qg4+ Kh8 26.Qxc4 + - [Q+P vs R+B]. D) 21... Bg7 22.Ng5 h6 23.Ngxe6 fxe6 24.Nxe6 Qd7 25.Nxf8 Rxf8 is unclear. I don't know, other moves like 21.Nxe6, 21.Rxe6, 21.d6, 21.dxe6, 21.Nxf5 don't look to me so promising. |
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Jul-31-10
| | agb2002: I considered 23.dxe6 hxg5 24.e7 but had the impression that Black ended up with clear material advantage. |
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Jul-31-10
| | agb2002: <Patriot:
...
Lesson: Look wide before you look deep.>
According to Alekhine and Krogius, that's why Capablanca lost the match in 1927. |
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| Jul-31-10 | | cjgone: To hard. |
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| Jul-31-10 | | David2009: <agb2002: [snip] 21.Ne4: A) 21... fxe4 22.Bxe4 (A) Rfe8 23.Qxh7+ Kf8 24.Nxe6+ Rxe6 25.dxe6 [snip] A.1.b) 25... Rxd1 26.Rxd1 Bxe4 27.Qxe4>
You have given some very fine and very comprehensive analysis including the moves found by Crafty End Game trainer defending the puzzle position as Black (a
link to the puzzle position set up on Crafty is in my earlier post D Valerga vs D Lemos, 2008). However, here Crafty finds the tougher defence
27... Nd5 instead of 27... fxe6 in your analysis to give
click for larger view
This is much tougher for White to win. Here is a link to try to win against Crafty EGT:
http://www.chessvideos.tv/endgame-t... |
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Jul-31-10
 | | al wazir: <gawain: 28. Rd8 Qc6+ 29. f3> Ng6. If now 30. Qxf5, then 30...Nxe7! 31. Rxe8+ (31. Rxe7? Rxd8) Qxe8 32. Qe4 Kf8.
click for larger viewIt's cramped, it's ugly, it's probably losing, but it's not "wrapped up" yet. |
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| Jul-31-10 | | BOSTER: <dzechiel> <taking the knight is no good> , and gave this line <21.Ne4 fxe4 22.Bxe4 Rfe8 23. Qxh7+ Kf8 24. Nxe6 fxe6 25.Qxc7>.
But what is wrong with 24....Rxe6 25.dxe6? BTW. My comment has mistake. 22....Rfc8?
I don't think that line in the real game after move 21.Ne4 is the best. |
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Jul-31-10
| | agb2002: <David2009: <agb2002:
...
However, here Crafty finds the tougher defence 27... Nd5 instead of 27... fxe6 ...This is much tougher for White to win. Here is a link to try to win against Crafty EGT: http://www.chessvideos.tv/endgame-t...; Probably the best strategy for White is to roll the king side pawns combined with threats against the king. |
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| Jul-31-10 | | wals: The game was just about even until
Black, on move 20 pulled the wrong rein and played Nc4 which gave White
the equivalent of a 2.54 pawn lead.
Any of the following would have kept Black in the game:-Analysis by Rybka 3 1-cpu:
1. = (0.03): 20...b5 21.Nf3 Nxf3+ 22.Bxf3 Bc8 23.Rd2 Rd6 24.Rc2 Qb6 25.Ne2 Bb7 26.dxe6 2. = (0.05): 20...Bg7 21.Nf3 Nxf3+ 22.Bxf3 Bc8
3. = (0.16): 20...Kh8 21.Rc1 Qe7 22.Kh2 Qd6 23.Rcd1 Nc4 4.  (0.26): 20...Qe7 21.Re3 Qc7 22.Nf3
5. (0.30): 20...Ba8 21.Nf3 Nxf3+ 22.Bxf3 Rd6 23.dxe6 fxe6 24.Rxd6 Qxd6 25.Bxa8 Rxa8 26.Qf3 Rf8 27.Rd1 Black sort of went downhill,
27...Ne5 -5.62. (White's 28.Rxe5 cut some slack reducing it to +4.48) White for some reason played,
32.b4 a blunder putting Black right
back into the game with a gain of 0.88th of a pawn. b3 +4.96 was the go. Then Black with some kind of a death wish played its blunder,
32...a5, +8.73. Much, much better was Bf6, retaining its advantage
of 0.88.
There were other inferior moves by both sides but Black was unable to recover. |
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Jul-31-10
| | gawain: Al Wazir are you still there? <al wazir: 28. Rd8 Qc6+ 29. f3 Ng6. If now 30. Qxf5, then 30...Nxe7! 31. Rxe8+ (31. Rxe7 Rxd8)> Unless I am looking at the wrong position, 31 Rxe7 wins, as 31... Rxd8?? allows 32 Qxf7+ and then mate <Qxe8 32. Qe4 Kf8.> So the diagrammed ugly but defensible position is only reached if White tries my suggested variation but misses the right 32nd move and also overlooks a better choice at move 30 of this variation. (However I grant your point about this not being wrapped up as neatly as I thought.) Anyway after 28. Rd8 Qc6+ 29. f3 Ng6. I would consider 30 Qxf5 but rather Qc1 (computer idea) (That's the better choice) 
click for larger viewand in this variation Black has (I think) nothing better than to allow the Q trade 30...Nxe7 31 Qxc6 Nxc6 and it's hopeless. I don't think that 30...Qb5 or Qa4 help. |
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| Jul-31-10 | | Patriot: <agb2002: <Patriot:
...
Lesson: Look wide before you look deep.>
According to Alekhine and Krogius, that's why Capablanca lost the match in 1927.> They said considering more candidates before analyzing a single candidate in-depth caused Capablanca to lose the 1927 match? I'm very curious! |
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| Jul-31-10 | | CHESSTTCAMPS: I had limited time to look at this today, but decided on 21.Ne4 (after looking at alternative candidates 21.Rxe6 and Nxf5) with the idea that white must keep the f7 pawn fixed in order to seal the BQ from the defense of h7, the principle target in view of the weaknesses of the pawn structure. The main line seems to be: 21.Ne4
A) 21... fxe4 22.Bxe4 Re8 (forced) 23.Qxh7+ Kf8 24.Nxe6+ Rxe6 (fxe6 25.Qxc7) 25.dxe6 Rxd1 (Bxc3 26.Rxd8+ Qxd8 27.Qxf7#) 26.Nxd1 Bxe4 27.Rxe4 Nd6 (Ke8 28.Qg8+) 28.e7+! Bxe7 29.Qh8# B) 21...Bxd4 22.Ng5 f6 23.Nxe6 Q moves 24.Rxd4 wins at least an exchange+P. C) 21...Bg7 looks like the best defense.
Time to check... |
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| Aug-01-10 | | CHESSTTCAMPS: My instincts were right, but I didn't do enough analysis on 21... Bg7 to earn the cigar. |
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| Aug-01-10 | | jheiner: 21.White to play.
Material N for DSB. Complex position with a lot of pins and xrays. The LSB on b7 and g2 vie for the long diagonal. For White, Pa2 and Pd5 are en prise; Nd4 is loose. For Black, Pe6 is en prise. The Black K has two legal moves g7 and h8, but is currently protected from check. The DSBf6 and Pawns on all light squares protect the K. If that DSB were to be removed that would loosen up the position around the Black K. Since Black has both B there's not technically a
weak color complex, but the LSB can't get to the area around the K and since White has both N, attacks could come on either color. Candidates: 21.Ne4
21...fxe4: Black can't simply capture with the P as 22.Bxe4 threatens 23.Qxh7# which is indefensible. 21...Bxe4 22.Rxe4 and Black must move or protect the Nc4. 22...Nxb2 or 22...b5 but Qg5+ is coming with dangerous possibilities. Maybe Qf6+ and the Re4 comes to h4. 21...Be5 (or 21...Bg7) 22.Ng5 (threatens mate on h7) f6 23.Nxe6 is crushing. 21...Be7 22.Ng5 (again threatening mate) Bxg5 23.Qxg5+ Kh8 24.dxe6 fxe6 (else 25.d7) 25.Nxe6 looks winning. 21...Qd7 22.Nc6! Bxc6 23.dxc6 (threatening the R coming into d7) Rxe1 24.Rxe1 (restores the threat) Rd8 25.Rd7 Rxd7 26.cxd7 and if Qxd7 27.Nxf6+ wins the Q. Again, note that at no time can Black take off the Ne4 as the recapture Bxe4 is indefensible. Let's see the game and kibitzing.
Hmmm, credit today? I mentioned 21...Bg7 22.Ng5 but not 22...h6. However, the capture on e6 is fairly obvious as is the R fork. And I mentioned the d7 push in my Be7 line but didn't continue as it looks pretty bad for Black at that stage. This position was so complicated, I think I'm taking credit today as the game was a sub-tree of some of my variations, but the main ideas were here. Also, my refutation of Qd7 was fun. To pick up <CHESSTTCAMPS> comment, I think I will take the Cigar today! |
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Aug-01-10
| | al wazir: <gawain: <28. Rd8 Qc6+ 29. f3 Ng6. If now 30. Qxf5, then 30...Nxe7! 31. Rxe8+ (31. Rxe7 Rxd8)> Unless I am looking at the wrong position, 31 Rxe7 wins, as 31... Rxd8?? allows 32 Qxf7+ and then mate <Qxe8 32. Qe4 Kf8.>> You're right.
So you're right about 28. Rd8 being a win. This shows that even a grandmaster doesn't see all the way through one of these "very difficult" puzzles, and it supports my belief that <CG> chose it as a puzzle only because the key move was found to be sound *after the fact*. If it hadn't worked out or if it worked only because Valerga's opponent missed the right defense, we wouldn't be seeing it. As always, I wonder what Valerga's thinking was when he played 28. Rd8. Did he think that it was a forced win, or a likely win, or was it just a stab in the dark? How are we supposed to learn to think like grandmasters if we don't know what their thoughts are? |
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Aug-01-10
 | | OBIT: After 21. Ne4 Bxc4, most posters are giving 22. Ng5, but IMO 22. Rxd4 is at least as good. In an earlier post, I analyzed 22...fxe4 23. Qg5+ Kh8 24. Qf6+ Kg8 25. Rdxe4 Rfe8 26. Rg4+ Kf8 27. de. Now the only move to stop e7+ followed by Qh8# is 27...Rxe6, but then 28. Rxe6, and there is still no way to stop Qh8#. If Black doesn't take the knight, the best try is probably 22...f6, which stops both Nf6+ and Ng5. However, then White has the following flashy attack: 23. Rxc4! Qxc4 24. Nxf6+! Rxf6 (or 24...Kg7 25. Qxh7+ Kxf6 26. Rxe6+ Kg5 27. Qh6#) 25. Qg5+ Kf7 (or 25...Rg6 26. Qxd8+ Kany 27. Qd7+ followed by Qxb7 wins) 26. de+ Rxe6 (26...Ke7 27. Qg7+ followed by Qxf6 wins) 27. Qxf5+ Ke7 (27...Rf6 28. Qxh7+ Kf8 29. Qe7+ Kg8 30. Qxf6 wins) 28. Qxh7+. After the rooks are exchanged and White grabs the bishop, he will have three pawns (all connected) for the exchange, which should win easily. |
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Aug-06-10
| | patzer2: I've been analyzing the position from last Saturday's July 31, 2010 puzzle solution, 21. Ne4!! for about a week now, as I find it one of the more interesting and complicated weekend puzzle positions and games we've seen in a while. The idea behind the move is that the exposed position of the Black King and the unprotected Queen give White a decisive material advantage if Black dares to take the sham sacrifice (i.e. 21. Ne4!!). For example, after 21... fxe4 (taking the bait), White is winning after 22. Bxe4 Rfe8 23. Qxh7+ Kf8 24. Nxe6+! Rxe6 25. dxe6 Rxd1 26. Rxd1 Bxe4 27. Qxe4  , when White with a Rook plus three extra pawns for a couple of lonely minor pieces and almost no pawn cover for the exposed Black King has all the winning chances. After the expected decline of the sacrfice offer with 21...Bg7, the reply 22. Ng5! gives White a decisive advantage against the weakened castled position. White got into trouble with some of his deep followup, as when he played 32. b4?, which would have allowed Black winning chances after 32...Bf6!  . Instead, 32. b3! Bf6 33. a4 Qc6 34. Qh6 Bxe7 35. Qxc6 would have won easily. Fortunately for White, Black overlooked the chance to turn the tables and win with 32...Bf6!, and instead lost after 32...a5? 33. g4! . P.S.: Another interesting aspect of this game is that 21. dxe6!? is playable, and is probably White's second best move. Indeed, Black has to play accurately to avoid losing quickly, but appears to equalize after 21. dxe6!? Rxd4! (21... Bxd4? 22. Rxd4 Rxd4 23. Qg5+ Kh8 24. Qf6+ Kg8 25. Qxd4 ) 22. Rxd4 Bxd4 23. exf7+ Qxf7 24. Qg5+! Kh8 25. Re7 Qg8 26. Qxg8+ Rxg8 27. Rxb7 Nxb2 28. Ne2 Bc5 =. |
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Kibitzing
sac: 23.dxe6