< Earlier Kibitzing · PAGE 4 OF 4 ·
|Jun-10-11|| ||MiCrooks: Not a flawed combo exactly as it does lead to about the same White advantage as anything else, but it does so at the commitment of a piece requiring accurate play on both sides. It also gives Black the chance to screw up and walk into mate as he did in the game.|
Objectively Qh5 is best. Most of the critical lines have been looked at...I saw that Scormus wanted to sack Ng6 on move 2...a bit a patience sir :)! After h6 Rad1 Bd6 (others are worse) THEN Ng6 works out even better.
|Jun-10-11|| ||Marmot PFL: This looks like a double bishop sac with Rd1 thrown in... helped by some awful defense by black, who seemed determined to play the whole game without his queen side pieces. 18... Qe8? is incredibly bad and Nd7 or Bd7 makes the win much harder to prove. for instance 18...Nd7 19 Rd3 Bh4 20 Rh3 Qg5 and white still has some work to do.|
|Jun-10-11|| ||Once: <patzer2> The plot thickens!|
When I first looked at this with Fritz, 16. Qh5 scored much highly than 16. Bxh7+. 16. Qh5 was scoring in the mid +2s and 16. Bxh7+ was duckeggs levelish. Conclusion: advantage 16. Qh5 as the best move and a spoiler puzzle.
But both you and Simon have shown that there is more to 16. Bxh7+ than ovoid equality.
I've since had Fritz chew on the position after 16. Bxh7+ Kxh7 17. Qh5+ Kg8 18. Rad1 Bd7 19. Rd3 e5
After 40 minutes, the eval has got to +1.67. That's a handy advantage for white, but not conclusive. And not yet as high as the original score for 16. Qh5.
The line that Fritzie is favouring right now is 20. Bxe5 Bh4 21. Rfd1 Re8. And at 45 minutes in, the eval has just taken a tumble to +1.37.
So I'm really not sure how to call this one. 16. Bxh7+ may not be the lemon that it first appeared, but it is taking a heck of a lot of silicon to try to find a win from it. The defence that black tried (18...Qe8) was certainly poor.
Hmm ... I really don't know. Did chessgames really intend us to use this amount of computing power to come to a conclusion on this one? Or did they think that 18....Bd7 refuted the 16. Bxh7+ sac?
Perhaps this is a spoiler spoiled?
|Jun-10-11|| ||Marmot PFL: <Objectively Qh5 is best.>
I spent some time there but didn't find anything concrete after h6, or f5 though white has a big edge. In some lines the knight would like h5 as well. For instance 16 Nh5 g6 17 Qd2 Bg5 18 f4 Be7 19 Qc3 f6 20 fg6 looks very strong.|
|Jun-10-11|| ||patzer2: <hedgeh0g: Only other defence I see is 19...e5> Yes! That's the one that puts up the most resistance. |
After 19...e5 (diagram below)
click for larger view
White wins following 20. Bxe5 Bf6 21. Bxf6 Qxf6 22. Nd5! (diagram below),
click for larger view
when play might continue 22...Qd8
(22... Qh6 23. Qxh6 gxh6 24. Nc7 Bf5 25. Rg3+ Kh8 26. Nxa8 Rc8 27. Re3 Nd7 28. Rd1 Rxa8 29. Rd5 Bg4 30. Rd4 Nf6 31. Rf4 Rd8 32. h3 Kg7 33. Rg3 Rd1+ 34. Kh2 h5 35. c4 Kg6 36. c5 Kg5 37. Rc4 Kh6 38. hxg4 Nxg4+ 39. Rgxg4 hxg4 40. Rxg4 )
23. Re1 Re8 24. Rxe8+ Qxe8 25. Re3 Be6 26. Nc7 Qc8 27. Nxa8 Qxc2 28. h3 Qd2 29. Qc5 .
|Jun-10-11|| ||gofer: Black is quite under-developed with 4 pieces still on their original squares, white just has two. So the Bxh7+ sacrifice screams to be played, but is it sound?! Well it looks like black simply
accepts and 16 Bxh7+ Kxh7 17 Qh5+ Kg8 it becomes obvious that Bxg7 needs to be played too and then white starts giving up rather too much material. So I then looked at 16 Bxg7! but even this seems
a little complicated. 16 Bxg7 Kxg7 (17 Qg4+ Bg4 maybe its winning) 17 Qh5 f5 errr...|
So I went back and looked at not giving up a bishop quite so readily!
<16 Qh5 ...>
16 ... g6 17 Nxg6 fxg6 18 Bxg6 Rf7 19 Bxf7+ Kf8 20 Qxh7 Bh4/Bg5 21 Rd1 mating
16 ... h6 17 Bxg7! Kxg7 18 Qe5+! (Kg8 Nh4 mating) f6 19 Qh4!
19 ... Qe8 20 Qg4+ Kh8 21 Ng6+ winning with a knight windmill
19 ... Rg8 20 Qg6+ Kf8 21 Qxh6+ (Rg7 22 Nh4 winning) Ke8 22 Bg6+ Kd7
23 Rad1+ Be6 24 Rxd6+ Kxd6 25 Rd1+ Kc7 26 Rxd8 Rxd8 27 h4 winning)
<16 ... f5>
<17 Rfe1 ...>
the weakness of Pe6 is enough to win. One such variation is...
<17 ... Qe8>
<18 Qxe8 Rxe8>
<19 Nxe6 Bxe6>
<20 Rxe6 g6>
Black's act of saving Pf5 creates huge longterm problems...
<21 Bc4 Kf8>
<22 Rae1 ...>
22 ... Nd7 23 Bg7+ winning
In most of the following black has to be very careful to not allow Bg7+ forcing the king to take and then end up losing the exchange on e7 or e8
<22 ... Nc6>
<23 Bd5 Rc8>
<24 c4 Rc7>
<25 Bc1! ...>
25 ... Kg7 26 Bxc6 bxc6 27 Bf4 Rd7 Rxc6 winning
25 ... Rd8 26 Bh6+ Ke8 27 26 Bxc6+ bxc6 27 Bf4 Rcd7 28 Rxc6 winning
Time to check...
I have looked at a few posts and I felt the double bishop sac was way too risky given how strong white's attack is. Okay in the continuation played it looks fine, but I felt black should have kept his queen on d8 and then thrown the bishop to g4 and then given it up later on after all white has already given up two bishops!
|Jun-10-11|| ||gofer: Ahhhh, the cat that has got the cream...
Didn't get too much work done today though...
|Jun-10-11|| ||Fezzik: I'm convinced: 16.Bxh7! is spectacular and works. 16.Qh5 is not spectacular and also works. |
Both moves win, so 16.Qh5 is not a true spoiler since 16.Bxh7 does lead to a win.
|Jun-10-11|| ||patzer2: <Once> After 16. Bxh7+ Kxh7 17. Qh5+ Kg8 18. Rad1 Bd7 19. Rd3 e5! 20. Bxe5 Bh4! (diagram below) I think you've found a continuation that gives Black some practical chances to save his game, but it will be very difficult.|
click for larger view
From here my move by look with Fritz 10 goes 21. Rfd1 Re8 (diagram below)
click for larger view
21. Bxb8! Rxb8 22. g3 Re7! 23. Qxh4 to when Black must find 23...Qe8! (diagram below) to have any survival chances.
click for larger view
Now 24. Ng2! Bc6 25. c4! Bxg2 26. Kxg2 and with two extra pawns and no real weaknesses in his position, White has excellent winning chances.
|Jun-10-11|| ||Once: Yes, but that's a long long way from the puzzle position - and we've both thrown a lot of silicon at it. I've now had Fritz working for more than 3 hours and still have only found a white edge of +1.41 after 19...e5|
I wonder what CG meant for us to find today?
|Jun-10-11|| ||scormus: <Once ... spoiler spoiled? ... silicon?> Yes, my thougts too. I could accept such a difficult puzzle on a Sunday, but I'd like to think a good enough player could make the right call on any weekday without needing the NASA supercomputer. |
My question for <CG>, "would you have given this as a friday puzzle if B had played 18 ... Bd2! instead of ... Qe8?" ?
|Jun-10-11|| ||k.khalil: This game reminded me of one of Garry Kasparov's famous games. The two stealth jet planes lurking on the top right side ready to strike. It's such an aesthetic appreciation game.
16. Bxh7+! kxh7
17. Qh5+ kg8
18. Rd5 Queen takes cover
19. Bxg7 Kxg7
20. Q on the g file and 21. R on the h file and # is inevitable.
|Jun-10-11|| ||Sho: What a third-rate player (me) can see:
the white bishop and queen move (16 and 17). Rook move (18): no, missed it. Black bishop (19): yes, see it but don't know how it helps. Queen move (20): yes, saw it but not sure when to make it.
Final judgement: Don't do 16 Bxh7+. And that would be why I'm a third-rate player.
|Jun-10-11|| ||BOSTER: To be honest I spent a lot of time,but I found the line exactly like in the game( with the exception only was black move 18.Qc7).
I guess it was very important before the second bishop sacr. play 18. Rad1 to see the black queen intenion. I did not see (or more exactly I did not want to see) Bd7 (or Nd7), but I'd play such line even with Bd7 defence.|
|Jun-10-11|| ||sofistis: very similar to Kasparov-Portisch 1983 (I mean the double sac). I didn't go into details but when you have seen the previous match you can quite easily see what the white should do.|
|Jun-10-11|| ||sofistis: actually, Kasparov's sacs were much deeper calculated as they involved many more moves but the motif is the same albeit easier here|
|Jun-10-11|| ||estrick: If this were an OTB game, I would play the bishop sacrifice on h7 almost without hesitation. I’ve done that many a time, although the attack has often fizzled out. Nevertheless, this position looks so promising, it has to work! |
Both bishops are bearing down on the Black king, and there’s no Black knight on f6 to defend h7, h5, g4. The White knight is not on its usual square for joining in on the attack, on the other hand, it’s not blocking queen’s path to h5, either. If Black doesn’t accept the sacrifice on h7, Black has no way to avoid mate after 16 …Kh8; 17 Qh5.
After 16 … Kxh7; 17 Qh5+ the king will be forced to go back to g8. Lasker’s double bishop sacrifice seems indicated; Black will have to accept the second bishop, or get mated immediately. But here’s where my attack might typically fizzle out. If I play 18 Bxg7 Kxg7; there’s no useful check to follow up with, as Black controls the g5 and f6 squares with the bishop, supported by the queen, which means if White checks from g4 or e5 Black will be able to block it. The knight can’t give check until after the queen vacates h5, but that will give Black time to shore up his defenses.
Lacking deep calculation skill for long variations, but still believing that this attack must work, I “cheated” and clicked the game through move 17. So far, so good.
. . . 18 Rd1 . . .
Yes, that is the game continuation!
The problem with my calculations is that even though I could see the possibility of forcing the Black queen away from d8 so that Black would not be able to interpose with his bishop on g5 or f6, before making the initical sacrifice on h7, I couldn’t be sure that the Black queen had no useful square to go to. Now it’s clear that she doesn’t, so the rest is academic.
|Jun-10-11|| ||wals: Rybka 4 x 64
Looking good 8.Bd3 =0.10
8...d5. +0.55. Best, e5, =0.10. 0.44 penalty
15...Qd8 +1.43. Best, Qg5 +0.92. 0.51
18...Qe8 +#10. Game over for Black.
1. (#10): 19.Bxg7 Kxg7 20.Qg4+ Kh6 21.Rd3 Qd8 22.Rh3+
Bh4 23.Rxh4+ Qxh4 24.Qxh4+ Kg7 25.Qg5+ Kh7 26.Nh5 Rg8 27.Nf6+
|Jun-10-11|| ||estrick: Ha-ha! So, 18 Rd1 doesn't lead to a conclusive win after all, if Black defends with 18 ...Bd7. |
I probably would've continued with 19 Rd3 and 20 Bxe5, but according to other posters, would still have had a lot of work to do, with ample opportunity to blow it.
|Jun-10-11|| ||sevenseaman: There are two things; to start with there is the POTD that we all know being as close to OTB as is possible in a non-live game. (the POTD aim)|
Then we have the double dummy (a term from contract bridge whence all cards are known) search for a win with no holds barred.
Both end up teaching one a lot, contingent on the availability of time.
|Jun-10-11|| ||perfidious: <sevenseaman: Then we have the double dummy (a term from contract bridge whence all cards are known) search for a win with no holds barred.>|
Double dummy (as in one mistake, dummy, then another, dummy) might well have been applicable to most of my career at master level, during which I routinely got into time trouble at the drop of a hat whilst looking for the best move in about every position.
Trouble was, you all know the rest.....up to twenty moves in one or two minutes, then hours to contemplate the wreckage resulting therefrom.
It was reading Dvoretsky's advice and applying what I learnt that finally cured me of the habit. By then, though, I was well on the way to being the hasbeenusetawas that I am today.
|Jun-10-11|| ||sevenseaman: <perfidious> You have stretched it a bit to suit your need.|
Bridge term 'Double dummy' in chess corresponds to knowing all possible implications/effects of any given move. That obviously includes all cumulative knowledge as well as possible silicon aided research, except maybe your own invention by way of a novelty.
<Sport is more about instinct than intellect. Intellect is the primary requirement while planning but once the game starts, instinct must take over.>
|Jun-11-11|| ||Dr. J: Let's see: at move 16 in a not-especially-noteworthy game, we have an open position with equal material and no real weaknesses for either player, but Black is behind in development.|
And after hundreds of hours of human analysis, and at least dozens of hours of computer analysis, we STILL don't know for sure what move is best.
I LOVE THIS GAME!!
|Jun-11-11|| ||M.Hassan: "Difficult" White to play 16.?
Forcs are equal.
So far in this line, the game has continued in a "not revolutionary" manner, but taking the Bishop on d7 starts some action on the part of White:
<22...Kh8 brings trouble: 23.Qh5 Nf6 24.Ng6#>
And after 10 moves, it appears that White is in a better combination and has material superiority
Time to check
|Jun-11-11|| ||SimonWebbsTiger: @Dr.J
I think the most meaningful comment on this problem might be hedgeh0g's, when he said the complications seem so bewildering on Bxh7 that in an actual game he would settle on Qh5 and a build up of the attack.
A very sensible, practical approach.
I bet hedgeh0g's avatar (Tal) would have let fly with Bxh7 even without full analysis!
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