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Later Kibitzing> |
| Jan-11-08 | | TrueBlue: OK, here is a line of the first two moves swapped, I believe it shows it works, please correct me if I am wrong: 22. Rd5 Qc7 23. Bxg7 Kxg7 24. Qg3+ Kf8
At this point black is toast: e.g.
1) 25. Qd8 Rh8 26 Re1 loses the queen
2) moving the e8 rook forward loses the a8 rook
3) 25. Ke7 Re1+ 26. Kd7 Qg4+ 27. Re6 loses the black queen 3)
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| Jan-11-08 | | goodevans: Assuming that the order of the first two moves isn't terribly important (which seems to be the consensus) then this seems far too easy for a Friday! |
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| Jan-11-08 | | znprdx: It seems to me that 22.Rd5 is preferable to the immediate Bxg7 because Black has Re6 as a defense |
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Jan-11-08
 | | pawn to QB4: on the other hand, if someone played 22.Rd5 against me and I foresaw the horrors awaiting me after 22...Qc7, I'd try 22...Nxc3 23.Rxc5 Ne2+ 24.K moves dxc5, and I suspect White would remember the rest of the game as a tedious slog v an oik who wouldn't resign, rather than the sparkler it is. So I think 22 Bxg7! preferable. |
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Jan-11-08
 | | johnlspouge: Friday (Difficult) White to play and win
Material Black N+P for B. White's Q, Rd1, and B mobile and able to strike at Black's K-side. Black's Q, N, and Ph5 are vulnerable; the N is unprotected and can be forked by Qe2 if Black's K runs across e7. Candidate moves: Bxg7 (ho-hum. Again!?!), Rd5, b4. I favor Rd5 then Bxg7 to encourage the Black K to run to the Q-side. 22.Rd5 Qa3 [Nxc3 23.Rxc5 Ne2+ 24.Kh1 dxc5 25.Qxh5 leaves White R+B for Q] The line seems stronger with transposed candidate move order. 22.Bxg7 Kxg7 23.Rd5 Qb4 24.Rg5+ Kf8
25.Qf6 is desirable, to force Re8 to maintain contact with Ra8 (or else Qh8+ picks up Ra8), to prevent the K escaping, and to prevent Rxh5 then Rh8+. Unfortunately, 25...Qc3 prevents the plan. Thus, the original move order seems preferable, as it restricts the Q's replies. 22.Rd5 Qa3 23.Bxg7 Kxg7 24.Rg5+ Kf8 25.Qf6 [threatening 26.Rxh5 and Rh8#] 25...Re1 moves along e-file drops the Ra8 to Qh8#
25...Re1 moves along 8th rank 26.Re1 and Qh8 will #.
No other defense alters the basic threat.
If 22...Q other, e.g., Qc7
22.Rd5 Qc7 23.Bxg7 Kxg7 24.Rg5+ Kf8 25.Qf6 Qd1 26.Qg7+ Ke7 27.Re1+ Kd7 28.Qxf7+ Re7 29.Qf5+ Kc7 I cannot force this line to a win. Because the Rg5 hangs, the Q cannot pick up the Na2 with a fork Qa5+. The best I find is 3Ps for N, but there are so many checks, and the Black K is so open, it's hard to believe the win is not there somewhere. Let's see how the game played out. Ahh! I missed 26.Qd6+. It is an interesting lesson on picking up minute advantages and restricting advantages by transposing move orders. |
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Jan-11-08
| | johnlspouge: <patzer2>: I am now very careful to avoid seeing the answer to the puzzles in the informative titles of your game collections :) |
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| Jan-11-08 | | zooter: <pawn to QB4: on the other hand, if someone played 22.Rd5 against me and I foresaw the horrors awaiting me after 22...Qc7, I'd try 22...Nxc3 23.Rxc5 Ne2+ 24.K moves dxc5, and I suspect White would remember the rest of the game as a tedious slog v an oik who wouldn't resign, rather than the sparkler it is. So I think 22 Bxg7! preferable.> Exactly -- I was just running through my computer and Spike 1.1 has this evalution at 16-ply +1.93 22.Rd5 Nxc3 23.Rxc5 Ne2+ 24.Kh2 dxc5 25.Qxb7 Nd4 26.Rb1 g6 27.b4 cxb4 28.Qxb4 Rad8 29.Qa4 Re7 30.c5 f6 31.c6 |
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| Jan-11-08 | | zooter: <johnlspouge: <patzer2>: I am now very careful to avoid seeing the answer to the puzzles in the informative titles of your game collections :)> Exactly....lucky for me today, I decided on Bg7 and then noticed the title...But who knows, if not for the title I might have looked at the position one last time and maybe changed my mind!! |
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| Jan-11-08 | | znprdx: Upon further review...I think this position "is much ado about nothing"....it doesn't really meet the standard of being a problem - and is certainly not a puzzle. A lot more challenging and even fun would be 22.Bb2 working on the out-of-play Knight. Even the simple Bd4 probably wins. |
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| Jan-11-08 | | JG27Pyth: After 27...Ke8 is there a forcing line to mate (beginning 28. Rd1 perhaps)? Or is the idea simply 28.Rg8+ winning the black rook at a8 with white up the exchange and the postion  ? |
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| Jan-11-08 | | zooter: Seems like Spike 1.1 again has a say on 22.Bxg7
It evaluates this move better than 22.Rd5 at 16-ply
+3.18 22.Bxg7 Kxg7 23.Rd5 Qb6 24.Rg5+ Kf8 25.Qxh5 Nc3 26.Rf5 f6 27.Qh6+ Ke7 28.Qxf6+ Kd7 29.Qxc3 Re7 30.Rd1 Qc6 31.c5 Rc8 32.Rfd5 Also notice that with accurate defense Black is well down, but certainly no way mated. One more interesting point is that the move forces the black king to take the bishop. I think this clearly shows that 22.Bxg7 wins On running the same engine on 22.? shows Bxg7 as +2.83 at 16-ply: +2.83 22.Bxg7 Kxg7 23.Rd5 Qb6 24.Rg5+ Kf8 25.Qxh5 Nc3 26.Rf5 Ne2+ 27.Kh2 f6 28.Rxf6+ Ke7 29.Rf7+ Kd8 30.Re1 Kc8 31.Rxe2 Rxe2 32.Qxe2 Qxb3 This shows that the advantage is only increasing after 22.Bxg7 even after best play by black |
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| Jan-11-08 | | parmetd: znprdx: Upon further review...I think this position "is much ado about nothing"....it doesn't really meet the standard of being a problem - and is certainly not a puzzle. A lot more challenging and even fun would be 22.Bb2 working on the out-of-play Knight. Even the simple Bd4 probably wins. good point |
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Jan-11-08
| | johnlspouge: <zooter>: I would not put much faith in a small difference in evaluations at long plies. I tried to figure out how some of the engine's algorithms actually work. I gave up, because nobody documents their practical <ad hoc> algorithms carefully anymore, for reasons of complexity. (The same issue comes up in my scientific work, and it is a real pain.) I doubt small differences mean much. |
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| Jan-11-08 | | Funicular: i quickly thought of Rd5 and then i guessed the bxg7 sac, without careful study i'd say the order didn't make a difference. Now computers prove me wrong :P |
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| Jan-11-08 | | MarkThornton: <20...Bxc3> looks like insane provocation to me. |
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Jan-11-08
 | | kevin86: It looks like a recent theme continues to flow: Sacrifice minor pieces to open up the adverse king position. Here,a bishop is "lost" so that a pair of rooks and queen can hound black's king to death. |
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| Jan-11-08 | | Dr. J: Thoughts:
1) The difference between the 22 Bxg7 and 22 Rd5 lies in what happens if Black does not move his Queen, viz:..A) 22 Bxg7 Kxg7, 23 Rd5 b6 (*), 24 Rxc5 dxc5, 25 Qxh5 ..B) 22 Rd5 Nxc3, 23 Rxc5 Ne2+, 24 Kh2 dxc5, 25 Qxb7 Nd4 (A) seems a much easier win than (B).
(*) Is there a better non-Queen move here?
2) Not considered in comments above is the defense ... Q-c7(or b6 or c8)-d8, specifically 22 Bxg7 Kxg7 23 Rd5 Qc7, 24 Qf6 Qd8 when I can find no clear win for White. I suppose this is why <Zooter>'s computer prefers (23 ... Qb6) 24 Rg5+ Kf8, 25 Qxh5 3) BUT ... why does <Zooter>'s computer prefer Qb6 to Qc7, which provides a much-needed defender for the f-pawn? How does White win then? |
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| Jan-11-08 | | zooter: <3) BUT ... why does <Zooter>'s computer prefer Qb6 to Qc7, which provides a much-needed defender for the f-pawn? How does White win then?> I'm very tired and its late in the night here. So i'm taking the easy route out by posting a 15-ply analysis by my computer which gives a huge advantage for white after 22.Bxg7 Kxg7 23.Rd5 Qc7
+5.42 24.Qg3+ Kf8 25.Rxh5 Re6 26.Rh8+ Ke7 27.Rxa8 Nb4 28.Rxa7 Nc6 29.Ra8 Qb6 30.Rd1 Ne5 31.Kh2 Kd7 |
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| Jan-11-08 | | TrueBlue: the 22. Rd5 Nxc3 gives clear advantage to white. Maybe your silicon brains don't show it, but a queen is extremely strong in such an endgame position. |
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Jan-11-08
 | | whiteshark: After <22.Bxg7 Kxg7 23.Rd5 Qb6> there is also the tricky <24.Rf5!!>
click for larger view
with <24...Qc7 25.Qg3+! > or <24...Re7> (blocking a flight square) <25.Qg3+ Kf8 26.Rg5! Re5 27.Rg8+ Ke7 28.Rxa8 > or <24...f6> but now <25.Rxh5! Rh8 26.Rb5> and infiltrating via b7 |
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| Jan-11-08 | | hovik2003: So much analysis for onesided game, black's position is hopeless no matter what white plays either Rd5 and Bxg7 have the same result. |
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| Jan-11-08 | | zb2cr: I only get 1/2 credit. I got the initial moves, but I missed Black's possible defense 25. ... Qc3--so I didn't prepare anything for it. |
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| Jan-11-08 | | wals: Lets find attacking moves. Whites has a superior pawn structure.
1.Rd1-d5 attacks the queen and h5 pawn..Qb5 (Qc6)
2.Bxg7...Kxg7 3.Rg5+ ...Kf8 4.Qxh5
check the results...
On the track sort of but lacking in finesse. |
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| Jan-11-08 | | DarthStapler: I thought of Rd5 first |
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| Jan-12-08 | | alphee: It was clear to me that the 2 main action points would be d5 and g7 but without a board I could not decide between the 2 following variations. 22. Rd5 Qc6 23.Bxg7 Kxg7 24. Rg5+ Kf8 25. Qf6
22. Bxg7 Kxg7 23. Rd5 Qc6 24. Rg5+ Kf8 25. Qf6
May be I missed something in the first one but it would have left to something like 25.... Re7 26. Qg7+ Ke8 27. Qg8+ Kd7 28. Qxa8.
Not sure which one I would have played, may be 22.Bxg7 to get the king out of its protecting wall first. |
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Later Kibitzing> |
Kibitzing
sac: 22.Bxg7