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Very Hot Topic (More than 25 Replies) C57: Two Knights 5...Nxd5 (Read 52613 times)
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Re: C57: Two Knights 5...Nxd5
Reply #70 - 11/04/14 at 19:55:10
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Knightcut wrote on 11/02/14 at 12:58:31:
Stefan Buecker wrote on 03/24/10 at 23:27:34:
Master Om claims a -/+ for 6.Nxf7?, because 8...Ncb4 is -/+, and that is certainly true, but not new. etc....


I think time is ripe to replace the "?" after 6.Nxf7 with "!?" or maybe even "!" in particular in light of Sloughters convincing analysis of 9.0-0! on it's own thread elsewere on this forum. One important point is that the former assumption that 9...c6 10.d4 Qf6 should be favorable for Black seems to be totally overturned by Sloughters 11.Qd1!+=.

So, wheter to prefer the Lolli with 6.d4 or the Liver with 6.Nxf7 nowadays seem to be more a matter of taste than a matter of objective assessment of strenght. It may be, however that the slight white plus for both lines is easier to convert in practise in the Lolli than in the Liver.


Say what? As far as I can remember, Sloughter's analysis has been made with some engine set to sub-optimal parameters (probably not validated or something).
  
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Re: C57: Two Knights 5...Nxd5
Reply #69 - 11/02/14 at 12:58:31
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Stefan Buecker wrote on 03/24/10 at 23:27:34:
Master Om claims a -/+ for 6.Nxf7?, because 8...Ncb4 is -/+, and that is certainly true, but not new. etc....


I think time is ripe to replace the "?" after 6.Nxf7 with "!?" or maybe even "!" in particular in light of Sloughters convincing analysis of 9.0-0! on it's own thread elsewere on this forum. One important point is that the former assumption that 9...c6 10.d4 Qf6 should be favorable for Black seems to be totally overturned by Sloughters 11.Qd1!+=.

So, wheter to prefer the Lolli with 6.d4 or the Liver with 6.Nxf7 nowadays seem to be more a matter of taste than a matter of objective assessment of strenght. It may be, however that the slight white plus for both lines is easier to convert in practise in the Lolli than in the Liver.
  
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Re: C57: Two Knights 5...Nxd5
Reply #68 - 11/02/14 at 12:41:40
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Stefan Buecker wrote on 03/30/10 at 22:52:08:
But 6. d4 Be6 7.Nxe6 is equal. Your logic is, well, surprising.


Stockfish5 confirms that 7.0-0! is whites best try for an advantage, but also gives a slight white plus after 6.d4 Be6 7.Nxe6 fxe6 8.0-0!

It seems to almost suggest a general rule of thump, namely that a quick 0-0 seems to be the best modern way for white to fight for an advantage in many of these obscure lines following 5...Nxd5, cf. also Sloughters convincing recommendation of 9.0-0! after 6.Nxf7 Kxf7 7.Qf3 Ke6 8.Nc3 Ncb4 in the Fried Liver. OK, this may seem to be a horrible simplification, but in messy lines like these some type of rule of thump could actually be helpful, I think. 

  
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Re: C57: Two Knights 5...Nxd5
Reply #67 - 11/08/12 at 03:13:51
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SWJediknight wrote on 11/07/12 at 22:43:04:
Earlier posts in this thread have given (9.a3 Nxc2+ 10.Kd1 Nxa1 11.Nxd5) 11...c6 and 11...Qh4 as leading to advantage for Black. Personally I find 11...Qh4 slightly the more convincing move of the two.

In my analysis file on the Fried Liver I have the following after 11...c6:
"The critical line runs 12.Nc7+ Kd7 13.Nxa8 Qh4. The problem is that Black is in a strong position to pick up the knight on a8 and develop a counterattack, e.g. 14.Qf7 Be7 15.Re1 b5 16.Ba2 Rf8. If White checks with 14.Qd3+, there follows 14Qd4 15.Qxd4+ exd4 and material is level but Black is slightly better due to the better-placed pieces and further-advanced pawns."

and after 11...Qh4:
A) 12.Nxc7+ Kd7 13.Qf7+ Qe7 14.Nxa8 Qxf7 15.Bxf7 Bc5 and despite temporarily being a pawn down, Black is better, as the a8-knight is doomed whereas the a1-knight can be saved via Kd6 and Bf5.

B) 12.Nb6+ (preventing Kd7) 12Ke7 13.Qf7+ Kd8 14.Nxa8, which at least keeps queens on the board, thus giving White more chances of building up a successful attack on Blacks exposed king. However, Black still stands better after 14Bd7.

It's possible that someone has improved on parts of that analysis earlier in the thread, but the general gist has always been that Black is better after 9.a3?!.



What is clear is the White had to meet 11...Qh4 with 12.Nb6ch (Not Nxc7ch) but Black still seems somewhat better after 12...Ke7 13.Qf7ch Kd8 14.Nxa8 Bd7.

It can be predicted that 9.a3? will ultimately be regarded as a weak move bordering on a blunder especially because White had four better moves i.e. 9.d4?! Nxc2ch 10.Kd1 Nxd4 = or 9.Qe4, 9.O-O, or 9.Bb3.
  
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Re: C57: Two Knights 5...Nxd5
Reply #66 - 11/07/12 at 22:43:04
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Earlier posts in this thread have given (9.a3 Nxc2+ 10.Kd1 Nxa1 11.Nxd5) 11...c6 and 11...Qh4 as leading to advantage for Black. Personally I find 11...Qh4 slightly the more convincing move of the two.

In my analysis file on the Fried Liver I have the following after 11...c6:
"The critical line runs 12.Nc7+ Kd7 13.Nxa8 Qh4. The problem is that Black is in a strong position to pick up the knight on a8 and develop a counterattack, e.g. 14.Qf7 Be7 15.Re1 b5 16.Ba2 Rf8. If White checks with 14.Qd3+, there follows 14Qd4 15.Qxd4+ exd4 and material is level but Black is slightly better due to the better-placed pieces and further-advanced pawns."

and after 11...Qh4:
A) 12.Nxc7+ Kd7 13.Qf7+ Qe7 14.Nxa8 Qxf7 15.Bxf7 Bc5 and despite temporarily being a pawn down, Black is better, as the a8-knight is doomed whereas the a1-knight can be saved via Kd6 and Bf5.

B) 12.Nb6+ (preventing Kd7) 12Ke7 13.Qf7+ Kd8 14.Nxa8, which at least keeps queens on the board, thus giving White more chances of building up a successful attack on Blacks exposed king. However, Black still stands better after 14Bd7.

It's possible that someone has improved on parts of that analysis earlier in the thread, but the general gist has always been that Black is better after 9.a3?!.
  
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fried liver
Reply #65 - 11/07/12 at 14:07:02
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SWJediknight wrote on 11/07/12 at 00:02:28:
After 9.a3?! Nxc2+ 10.Kd1 Nxa1 11.Re1?!, Black should defend the d5-knight with 11...c6, which also covers the b5-square. The position is still dangerous for Black, but with a few accurate moves Black should come out with a large, probably winning, advantage, e.g. 12.Nxd5 cxd5 13.d4 Kd7 14.dxe5 Bd6! 15.Qxd5 Kc7.

Thus 9.a3?! still looks to me like it leads to a significantly better position for Black, rather than a draw.


9.a3?! Nxc2ch 10.Kd1 Nxa1 11.Nxd5 (I gave the wrong move order. I forgot to include this) Kd6 12.Re1 Qg5 13.d4 Qg4 14.dxe5ch Kc6 15.Ne7ch =

or 11...Kd6 12.Re1 c6 13.Rxe5 Bd7 14.Rxd5ch +/-

or 13.Rxe5 Qh4? 14.Re4 +/-
  
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Re: C57: Two Knights 5...Nxd5
Reply #64 - 11/07/12 at 00:02:28
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After 9.a3?! Nxc2+ 10.Kd1 Nxa1 11.Re1?!, Black should defend the d5-knight with 11...c6, which also covers the b5-square. The position is still dangerous for Black, but with a few accurate moves Black should come out with a large, probably winning, advantage, e.g. 12.Nxd5 cxd5 13.d4 Kd7 14.dxe5 Bd6! 15.Qxd5 Kc7.

Thus 9.a3?! still looks to me like it leads to a significantly better position for Black, rather than a draw.
  
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Re: Two Knights 5...Nxd5
Reply #63 - 11/06/12 at 16:39:44
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Stefan Buecker wrote on 03/24/10 at 23:27:34:
Master Om claims a -/+ for 6.Nxf7?, because 8...Ncb4 is -/+, and that is certainly true, but not new. In the line 9.Qe4 his new move seems to be 14...Nf6! -+, when old theory was 14...Be7 15.f4 Nf6 16.Bxe6+ Nxe6 17.Qd3 Rf8 -/+, John Watson.
In the main line 9.a3 Nxc2+ 10.Kd1 my analysis in Kaissiber 12 (1999) claimed an advantage for Black after 10...Nxa1! 11.Nxd5 c6! (a move mentioned by Master Om as !?) 12.Nc7+ Kd6 13.Nxa8 Qh4!, improving upon old analysis by Palau (1949). Black has an advantage, though I said "perhaps White can hold the ending with precise play". My analysis ended with 22...Bxh8 -/+. I am not sure whether Master Om's 11...Qh4 is better than 11...c6, maybe it is. But the observation that 6.Nxf7? is -/+ isn't new.

6.d4 Be6!, recommended by De Zeeuw, is much more interesting. In Kaissiber 29 (2007) Maurits Wind studies it on 4 pp., and although he finds an advantage for White this line still deserves attention.


I don't like a3 because this is an extremely sharp position where every tempo counts. Not surprisingly this leads to a quick draw.

5.exd5 Nxd5 6.Nxf7 Kxf7 7.Qf3ch Ke6 8.Nc3 Nb4 9.a3?! (Both developing moves 9.O-O and 9.Bb3 are better while 9.d4 Nxc2ch 10.Kd1 Nxd4 looks equal---again because White focusses on the developing move d4, not the wasted tempo 9.a3. It turns out in this line that White has just enough attack to get a quick draw by repetition:

9.a3 Nxc2ch 10.Kd1 Nxa1 11.Re1 a6! (or Bd6 12.Bb5ch Ke6 13.Bc4) 12.Rxe5 Bd6 13.Bb5ch! axb5 14.Qh3ch Kc6 15.Qc3ch =



  
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Re: Two Knights 5...Nxd5
Reply #62 - 08/13/10 at 07:48:26
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kylemeister wrote on 03/22/10 at 17:59:15:
Master Om wrote on 03/22/10 at 17:35:32:
6.....Be6 is the move that white cant refute so easily. Black holds on its own after Qh5 or Qg4. Fried liver is a better option to play for black and you have better chances to win.


I would certainly think that the textbook 6...Be6 7. Nxe6 fe 8. de Nxe5 9. Qh5+ etc. is clearly better for White, i.e. a refutation.

I also don't get the comment about the Fried Liver being a better option to play for Black.

As said by bueker its 8....Bb4+ not Nxe5 and its draw with correct play.
  
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Re: Two Knights 5...Nxd5
Reply #61 - 06/03/10 at 21:58:46
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I think 13.Nxc8+ may well be White's best practical chance after the dubious 9.a3, but Black still stands better. 13...Rxc8 14.d3 may cause problems for Black if Black doesn't know the theory, but after 14...Kd8! (as correctly given by others) 15.Qd5+ Bd6 16.Be3, White is going to spend a bit of time picking up the knight on a1. There are many alternatives for both sides in Master Om's long variations, but White should not get enough for the exchange.

Even if White can make 13.Nxc8+ work there's also 11...c6!? as suggested by both Master Om and Stefan Bcker, which is also better for Black, e.g. 12.Nc7+ Kd7 13.Nxa8 Qf6 14.Qe3 Qg6.

My current opinion of the critical lines is as follows:

A) 9.0-0 c6 10.d4 Qf6 (10...exd4!? 11.Bf4 Qf6 12.Ne4 Qf5 13.Ng3 with a very messy position, probably about equal) 11.Qe2 Ke7 12.f4 (12.dxe5 Qg6 13.Rd1 is roughly equal) 12...Kd8 13.fxe5 Qg6 and now 14.Nxd5 and the riskier 14.Qd2!? are highly unclear, with equal chances.

B) 9.Qe4 c6 10.a3 Na6 11.d4 Nac7 12.f4 Kf7 13.fxe5 Be6 14.0-0+ Kg8, as previously mentioned, is probably the critical line after 9.Qe4. I think chances are roughly equal here, as Black's h8-rook is shut out of play and White has two pawns and a strong centre in return for the piece. The line 12.Bf4 Kf7 13.Bxe5 Be6 14.Qf3+ Kg8! is similar, though perhaps a slightly improved version for Black, e.g. 15.Ne4 Qh4 (15...h5!? 16.0-0 h4 17.h3) 16.Bd3 b5. Nonetheless I would hesitate to take Black in an OTB game here too.

I also had another look at those 14.0-0 Nf6 lines, and concluded that after 15.Bxf6 gxf6 (or 15...Qxf6!? 16.d5 Nxd5) Black emerges with an edge, but not -+ as originally suggested.
  
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Re: Two Knights 5...Nxd5
Reply #60 - 06/03/10 at 18:10:20
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g2-g4 wrote on 06/03/10 at 07:56:12:
Imho, Mr. Om has missed some points in his analysis of 6.Nxf7 variation. After his suggestion 11...Qh4 12.Nb6+ Ke7 13.Qf7+?! Kd8 14.Nxa8 Bd6? 15.Qxg7 Rf8 Black has a draw, but not more. 16.d3 Qg4+ (16...Bg4+ 17.f3 Qf2 18.Bg5+ Kc8 19.Be7! =) 17.Qxg4 Bxg4+ 18.f3 Rxf3 19.Bg5+ Kd7 20.gf Bxf3+ 21.Kc1 Bxh1 22.Kb1 =
But in this line the both sides have their improvements. 14...Bd7! is stronger and secures edge for Black, but White improves earlier. 13.Nxc8+! and game is far from clear. E.g. 13...Rxc8 14.d3 Kd8 15.Be3 or 15.Qd5+

I dont think so. 13. Qf7 is the only good move. Nxf8 gives white more problems. Like
13. Nxc8+ Rxc8 14. d3 Kd8 15. Qd5+ Bd6 16. Be3 Rb8 17. Kc1 Qe7
18. Bxa7 c6 19. Bb6+ Ke8 20. Qa5 Kd7 21. d4 Ra8 22. Qc3 Kc8 23. Kb1 exd4 24.
Bxd4 Re8 25. Ka2 (25. Kxa1 Bxa3 26. Kb1 Bb4 27. Qd3 g6 28. Rc1 Kc7 29. Bd5 Qd7 30. Bf3 Rad8 31. Qb5 Qf5+ 32. Qxf5 gxf5 33. Rc4 Ba5 34. Kc2 Bb6 35. Bc3 Bxf2
36. Rf4 Be1 37. Bg7 Rd7 38. Bf6 Rd2+ 39. Kb3 Re3+ 40. Ka2 Kd6 41. Rxf5 Ke6 25... Bxa3 26. bxa3
Rxa3+ 27. Qxa3 Qxa3+ 28. Kxa3 Nc2+ 29. Kb3 Nxd4+ 30. Kc3 c5 31. Bd3 g6 32. h4 Kc7 33. h5 Ne2+ 34.Kb3 Re6 35. hxg6 hxg6 36. f3 Nf4 37. Rh7+ Kd6 38. Be4 b6 *
  
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Re: Two Knights 5...Nxd5
Reply #59 - 06/03/10 at 07:56:12
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Imho, Mr. Om has missed some points in his analysis of 6.Nxf7 variation. After his suggestion 11...Qh4 12.Nb6+ Ke7 13.Qf7+?! Kd8 14.Nxa8 Bd6? 15.Qxg7 Rf8 Black has a draw, but not more. 16.d3 Qg4+ (16...Bg4+ 17.f3 Qf2 18.Bg5+ Kc8 19.Be7! =) 17.Qxg4 Bxg4+ 18.f3 Rxf3 19.Bg5+ Kd7 20.gf Bxf3+ 21.Kc1 Bxh1 22.Kb1 =
But in this line the both sides have their improvements. 14...Bd7! is stronger and secures edge for Black, but White improves earlier. 13.Nxc8+! and game is far from clear. E.g. 13...Rxc8 14.d3 Kd8 15.Be3 or 15.Qd5+
  
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Re: Two Knights 5...Nxd5
Reply #58 - 03/31/10 at 05:25:28
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Yes, the idea is 9. c3 Bc5, when c3 is no longer available to the Nb1.
  
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Re: Two Knights 5...Nxd5
Reply #57 - 03/31/10 at 03:33:57
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Stefan Buecker wrote on 03/31/10 at 00:14:24:
One could say that it is not really important, since your conclusions are the same. But Maurits Wind's result was that 6. d4 Be6 7. Nxe6(?) fxe6 8. dxe5 Bb4+! is equal, while in his opinion only 7. 0-0! secures some advantage for White.

Is the move 8....Bb4+ a Zwischenschach ? . The Idea is beautiful now i understand. This moves threats c3 which shuts Nc3 as the best move in many lines!!.
  
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Re: Two Knights 5...Nxd5
Reply #56 - 03/31/10 at 00:14:24
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One could say that it is not really important, since your conclusions are the same. But Maurits Wind's result was that 6. d4 Be6 7. Nxe6(?) fxe6 8. dxe5 Bb4+! is equal, while in his opinion only 7. 0-0! secures some advantage for White.
  
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