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Nikolai Krogius vs Oleg L Chernikov
USSR (1970)
Russian Game: Modern Attack. Center Variation (C43)  ·  1-0
ANALYSIS [x]

FEN COPIED

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Kibitzer's Corner
< Earlier Kibitzing  · PAGE 3 OF 3 ·  Later Kibitzing>
Jun-23-07  BobbyL: Realbrob, whoops, I didn't see 14. ...Nd7. That's will save the game for Black. I stand corrected. 14. Nf3 is not the perfect move.

Jun-23-07  willyfly: Okey - material is even. Black is behind in development and Black's ♕ is out in the open and completely undefended. White's ♕ ♗ ♘ and ♖e1 are in position for a mating threat. Black threatens cxd3. The thing that stands out to me is that the Black ♕ could be won outright if the ♙g7 could be somehow drawn off it's square but ♘xg7 and ♗xg7 both fail to accomplish that.

the mating plan 14 ♖e3... 15 ♖h3... 16 ♕xh7# fails because of the ♗c8 and there doesn't appear to be any way to remove it from the c8-h3 diagonal.

the ♖e1 cannot go to h4 via e4 because of the ♙d5 but that ♙ can be removed with 14 ♗xc4 dxc4 and now 15 ♖e4 threatens mate in 2. The h4 square cannot be defended without losing the ♕. Black will be mated. I think this is the solution - time to check.

-----
haha - it was a back rank puzzle all along - oh well - my record for Saturday puzzles remains unblemished

Jun-23-07  realbrob: <slomarko: easy puzzle. the winning move is Nf3 with the idea of jumping on g5. if black plays f6 then white simply takes with the bishop on g6.>

14.Nf3 Nd7 and Black is perfectly fine.

Jun-23-07
Premium Chessgames Member
  patzer2: For today's puzzle solution, 14. Nxf7!! initiates a deep demolition combination, which ends up with the White Queen and three pawns rolling over Black's hapless Rook, Bishop and Knight.
Jun-23-07  MostlyAverageJoe: <patzer2> Yeah, right. How do you roll over anything after the black refuses the knight sac and plays as described in my first post? Here's the position after 14. Nxf7 Qf6 15. Ng5 Qg7 16. Qxg7+ Kxg7 (white to move):


click for larger view

Jun-23-07  ppm: <whatthefat>,
To 14..Qd7, 15. Ne5, black could reply with 15..Qg7.
I agree 14..Qf6 is not strong for black (he would have to exchange his rook for white's knight). If white's plan here is to go a pawn up and split up black's defense (similar to yesterday's game), then I understand 14.Nxf7 is good for white, but I still think the line that black played is far from optimal.
Jun-23-07
Premium Chessgames Member
  Gilmoy: Looks like a Winawer. Even material. White leads by 3 tempi in Q-side development. Black threatens cxd3. White's Q pins g6 sideways to Black's Q.

Meta-thought: It's Sunday -- we must be bold. [A] 14.Be2 Nc6 would leave White congested. White's B has no great prospects anyways. Black can't easily defend h7 -- can White double on it with N or R? [B] 14.Bxg6 fxg6 seems to make Black's defense easier.

[C] 14.Nf3 Qf6 15.Ng5 Qg7.
[D] 14.Re3 cxd3 15.Rh3 Bxh3 oops.
[E] 14.Bxc4 dxc4 15.Re4 Qf6 (or 15..f5 16.Rh4 Qc7).
[F] 14.Nxc4 dxc4 15.Bxc4 Qf6 (Qc7? 16.Re4 g5 (Qxc4? 17.Rh4 mates) 17.Qxg5+ Kh8 18.Qf6+ Kg8 19.Re5 h6 20.Bd3 wins: Nc6 21.Rg5+! hxg5 22.Qxg5+ Kh8 23.Qh6+ Kg8 24.Qh7#).

Apparently, White must prevent Qf6. Also, his KR hasn't participated yet. Suggests:

[G] 14.f4 cxd3 15.f5 refutes Qf6 (Bxf5? 16.Rxf5 as g6 is pinned) 16.fxg6 Qg7 17.exf7+ [G1] Rxf7 18.Nxf7 [G2] Kh8 18.Ng6+ Qxg6 19.Qxf8+.

So now it's Black who has a problem in preventing 15.f5.

[H] 14..f5 (Bf5? 15.Bxf5) 15.Rf3 cxd3 16.Rh3 Qc7 17.Nxg6 (threatens Ne7+ cutting Black's Q from h7) hxg6 18.Qh8+ Kf7 19.Rh7#.

Black can't allow f5, can't recapture there, and can't seem to play f5 himself. At the least, Black has no time to take the B. It looks like White's plan of f4-f5-Rh3 outsprints Black's lazy Q-side.

<After checking solution:> I missed/rejected Nxf7 because of Qf6. I think my [G] line with Bxf5 ends up being fine for Black -- he just returns the piece and develops his Q-side.

Jun-23-07  beginner64: I have read through the Kibitzing, and have not noticed a satisfactory continuation to 14. Nxf7 Qf6.

Did I miss some post?

Jun-23-07  Fezzik: I was so proud of myself for working out the tactics from move 14-21 (they're all pretty much forced), but thought Black had slightly better than the game continuation, e.g. with 16...Nd7 instead of Nc6. If 16...Nd7, I had 17.R1e7!!

BTW, I had the transpositional sac Bxg6 before Re1 along with dzechiel.

This was a good Wednesday or Thursday puzzle. Almost everything is forced, but it's somewhat hard to work out because the line goes on for so long. Even so, this was fun!

Jun-23-07  Fezzik: Some thoughts from other kibitzers: 14...Qf6 is tantamount to resigning because 15.Ng5 threatens mate, giving White time to reposition his B on d3.

White would be a pawn and a million (ok, about 4) tempi up on Black. The books would say "and the rest is a matter of technique."

<Gilmoy> thought that today's Sunday. I love Summer Vacation (and yes, it does deserve to be capitalized)!

Jun-23-07  ounos: Missed it, but was close enough. I thought that after 16. ... Nd7 Black sufficiently reinforces f8 and Bxg6 won't work - but overlooked the killer 17. R1e7 :-/
Jun-23-07
Premium Chessgames Member
  fm avari viraf: My first thought was 14.Bxg6 but immediately rejected as Black would easily defend. So my next choice was 14.Nxf7 Rxf7 15.Re8+ Rf8 16.Rfe1 [threatening 17.R1e7 ] Nc6 is forced 17.Bxg6 hxg6 18.Rxf8+ Qxf8 19.Qxg6+ Kh8 20.Re8 Qxe8 [ not 20...Bd7 then 21.Qh6+ Kg8 22.Qxf8+ ] but I didn't analyse if Black declined the Knight.
Jun-23-07  vajeer: can black defend by
16...Bd7 instead of playing Nc6
Jun-23-07
Premium Chessgames Member
  kevin86: I missed this one. I looked for Re3 followed by Rh3. I nice combination! Black should have resigned after his queen was removed. The three passed pawns are pretty irresistable.
Jun-23-07  Crowaholic: 14. Nxf7 Rxf7 (Kxf7?? and mate in 2) 15. fxg6 hxg6 (..Qxg6?? Re8+ and mate next) 16. Re8+ Rf8 17. Rfe1 immediately stands out.

Two big questions: What's Black's best next move and how to counter it? And: Can Black choose to decline one of the two sacs?

First things first: 17. ..Nd7 protecting the rook seems to be punished with 18. R1e7 Qxe7 19. Rxe7 Rf7 20. Qxg6+ Kh8 21. Rxf7 and mate next.

Next idea is to defend e7 with another piece, the only way to do this is 17. ..Nc6. Now White has 18. Rxf8+ Qxf8 19. Qxg6+ Kh8 (..Qg7?? Re8#) 20. Re8 Qxe8 21. Qxe8+ Kg7 and White unfortunately has no checks.

Let's count material for once: White has a Q and 7 pawns, totalling 17 points. Black has R, B, N and 4 pawns, totalling 15 points. Not much of a difference, but still advantageous. OTOH, Black's king is exposed, the 3 White kingside pawns are very strong, and it seems the queen will be able to lock down the rook and bishop for a while. So basically White should win.

Better moves for Black than 17. ..Nc6? Probably not, but let's at least try Rxe8.

17 ..Rxe8 18. Rxe8+ Rxc8 and although Black is nominally a knight for two pawns up, the position of the king, rook and knight is so bad that White should win anyway.

So much for the (disclaimer: relatively) easy part. As is often the case, the toughest of questions Is acceptance of the sacs forced? Are there better defences that involve declining one offer or the other? First, what if Black doesn't take the knight? Obviously, a queen move is now necessary because the Q is en prise and a counter-threat on the white queen is not possible. Qf6 maybe? 15. Ng5 Qg7 (only way to defend against Qh7#, Re8+ to mate *and* queen capture?) 16. Qxg7+ Kxg7 17. Re7+

and now

17. ..Kf6 Rfe1 and there may be a forced mate, but in any case, 18. ..Rh8 19. Nxh7+ Rxh7 wins easily. [Correction after checking with computer: Rfe1 drops the knight, oops! Re5 threatening to fork K and R if B is taken is much better.] 17. ..Kh6 h4! and Black seems to be in a pitiable condition. 17. ..Kg8 Rxh7 18. cxd3 oops. Let's try again.
17. ..Kg8 Be2 is better and White should eventually win upon careful play. But this will not be that easy I guess.

Ok, so basically declining the knight sac seems way better for Black than accepting it.

Anyway, let's see if Black can do even better by accepting the knight but declining the bishop sac. White threatens Re8+, Qxh7+ and/or Bxf7.

15. ..Rf8?? 16. Qxh7#
15. ..Qc7 Re8+

15. ..Qd7 16. Bxf7+ Qxf7 (..Kxf7? Qxh7+ followed by Qxd7 Bxd7 and a White endgame win). 17. Qg5+

and now

17. ..Qg7 18. Re8+ Kf7 19. Re7+ game over.
17. ..Kf8 18. Qd8+ Kg7 19. Qxc8 winning
17. ..Kh8 18. Qd8+ Kg7 winning in the same way, or ..Qg8 19. Re8 winning [Ok, my computer says: Qf6+ followed by Re8#. Could've seen that one.]

15. ..Bd7?? 16. Bxf7+ Kxf7 17. Qxd6
15. ..Rg7? 16. Bxh7+ and 17. Qxd6

To recap, Black's best option is probably to refuse the knight sac and play Qd6-f6-g7 instead. But White should win the endgame upon careful play. Looking at the solution...

Seems I got this line but with a transposition: White plays Re8+ before the B sac. Does not seem to make much of a difference except possibly allowing more (winning) lines.

And Black seems to have missed the knight refusal defence, or I may have missed an easier win for White in this line.

Jun-23-07  Crowaholic: <Fezzik: Some thoughts from other kibitzers: 14...Qf6 is tantamount to resigning because 15.Ng5 threatens mate, giving White time to reposition his B on d3.>

Err, so what? After 21. Qxe8+, White was the equivalent of two pawns up, Black's king was exposed, and the kingside pawns were going to kill Black whose only hope would be a major blunder by Krogius. Still, Chernikov played on for 10 more moves. I'm sure he would have been happy to try and draw the position that results from 17. Re7+ Kg8 18. Be2 in the 14. ..Qf6 line, *if only he had found it*. Also note that saving the bishop blocks the e file for the f1 rook, and White will need another tempo to clear it, which makes at least 3 more tempi for activating this rook.

Jun-23-07  Pawsome: <Fezzik: Some thoughts from other kibitzers: 14...Qf6 is tantamount to resigning because 15.Ng5 threatens mate, giving White time to reposition his B on d3. White would be a pawn and a million (ok, about 4) tempi up on Black. The books would say "and the rest is a matter of technique."> I don't believe it's all that simple. Black can claw a few tempi back and seems to be able to defend. Things might go like this: 14. Nxf7 Qf6 15. Ng5 Qg7 16. Qxg7+ Kxg7 17. Be2 h6 18. Nf3 Nc6 19. Ne5 Nxe5 20. dxe5 Be6 21. Rd1 Rac8 22. Rd4 Rc5 23. Rb1 b6 when white is clearly on top, but winning ain't so easy.

Jun-23-07  MaxxLange: I saw the first key, and the second, but my idea was to play Rf8+, then Bxg6 and THEN double rooks. I bet that's already been refuted in the above analysis
Jun-23-07  Timex: This game is a good example showing that a weak kingside can not only be exploited with sacs and mating threats, but with cover removal as well. In this case, the cover for the king is the pawns.
Jun-23-07  Fezzik: I took a look at the comments of <Crowaholic> and <Pawsome> and decided to try out the continuation with 14...Qf6 on my computer.

Even though I used a computer for the following lines, I don't pretend they represent an exhaustive analysis. Rather, the main line shows just how good White's game is with Queens off the board. One of many positional factors in White's favor is that Black's pawn chain is on d5 and c4 (light squares) in a light-squared Bishop ending.

Oh yeah, don't forget that White's a pawn and initiative ahead. The fact that I was able to defeat Fritz 9 from this position doesn't reflect my strength, but the strength of the position.

Me vs Fritz 9 from the stem game.

1.Nxf7!! Qf6 2.Ng5 Qg7 (forced) 3.Qxg7+ Kxg7 4.Be2 [Better than 4.Re7+ Kf6! which gets White into heaps of trouble] 4...h6 (creating a logjam on f3. I don't know if I would have played it, but it does seem to be Black's best.) 5.Nf3 Na6

[I gave this move to Fritz because 5...Nc6 6.Bd1 Bf5 7.Re3 Rae8 8.Rfe1 is devastating. The idea is to create counterplay with Nc7-b5, but Fritz never finds a way to do this.) The fatal weakness for Black throughout these lines is the d5 pawn.]

6.Ne5 Nc7 7.Bf3 b5 (I didn't understand at first why it would prefer the text to 7...b6. The problem with 7...b6?? is 8.Nxc4!) 8.Nc6 Be6 9.Re2 Rae8 10.Rfe1 a6 11.Nb4 (Ironically, *White's* Knight gets in the attack first.) Kf7 12.Kf1 a5 13.Nc6 Kf6 14.Re3 (This is mostly a waiting move. Black's in virtual zugzwang here!) Bf5 (The computer kept trying different ways to trade down. I think a human would have realised he was lost without the rooks.) 15.Rxe8 Rxe8 16.Rxe8 Nxe8 17.Bxd5 Nc7 18.Bf3 Fritz 9 gave the entire variation as winning for White, and claimed that White has more than a 2 pawn advantage in the final position.

Jun-24-07  MostlyAverageJoe: <Fezzik: Me vs Fritz 9 from the stem game.

1.Nxf7!! Qf6 2.Ng5 Qg7 (forced) 3.Qxg7+ Kxg7 4.Be2 h6 5.Nf3 Na6

[I gave this move to Fritz because 5...Nc6 6.Bd1 Bf5 7.Re3 Rae8 8.Rfe1 is devastating. The idea is to create counterplay with Nc7-b5, but Fritz never finds a way to do this.) The fatal weakness for Black throughout these lines is the d5 pawn.]>

I don't think I agree with the reasoning above. Yes, Na6-Nc7 protects the pawn, but Nc6 prevents white from attacking it easily and guards the e7 agains white's rook excursion. After black responds 8 ... Rf6, the position is:


click for larger view

and what is white to do now? Neither the white ♘ nor the ♖ can get close to the pawn, and Rd6 will defend it if white moves the ♘ and attacks with Bf3. Exchanging the knights after white plays Ne5 will allow black to take out the a-pawn, and have a counterplay with his own a-pawn. But let's continue with your line:

<6.Ne5 Nc7 7.Bf3 b5 (I didn't understand at first why it would prefer the text to 7...b6. The problem with 7...b6?? is 8.Nxc4!)>

I don't see why Fritz moved the b-pawn at all. This is the 20th move of the game, so how about developing that bishop to somewhere useful and connecting the rooks instead? Bf5 looks more useful to me.

<8.Nc6 Be6 9.Re2 Rae8> Why not Rf6 instead?

<10.Rfe1 a6 11.Nb4 (Ironically, *White's* Knight gets in the attack first.) Kf7 12.Kf1 a5 13.Nc6 Kf6 14.Re3 (This is mostly a waiting move. Black's in virtual zugzwang here!) Bf5 (The computer kept trying different ways to trade down. I think a human would have realised he was lost without the rooks.) 15.Rxe8 Rxe8 16.Rxe8 Nxe8 17.Bxd5 Nc7 18.Bf3 Fritz 9 gave the entire variation as winning for White, and claimed that White has more than a 2 pawn advantage in the final position.>

Indeed, the final position evaluates at +2.42 in Hiarcs. It seems that Fritz blundered a couple times (or you did not let it think long enough), because after your Na6-Nc7, it was only +1.21.

The devastating line evaluates at +0.59 as shown in the diagram above (Hiarcs confirms that the moves you suggested were strongest for both sides).

All analysis 20 plies deep.

BTW, Hiarcs did not want to trade the rooks. Valuation before Bf5 was +1.42, afterwards jumped to +2.23. Another place where it would play differently from Fritz is the aforementioned Rf6 (+1.19), not Rae8 (+1.57). The b-pawn versus Bf5 was my own idea, but Hiarcs evaluates them as about equal (1.19 vs 1.21).

Jun-24-07  Crowaholic: <Fezzik>, Black has at least as much hope after 14. ..Qf6 15. Ng5 Qg7 16. Qxg7+ Kxg7 17. Be2 as after 21. Qxe8+ Kg7 as played in the game, but very probably much more so. Actually, I'm no longer sure whether White is winning in the Qf6 line, for reasons see below.

As a matter of fact, at (maximum) depth 23, the Spike 1.1 engine gives a score of +3.72 after 21. Qxe8+ Kg7. It is not hard to see why: White has +2 pawns more material, and, more importantly, three connected passed pawns on the kingside, while Black has no convincing way of stopping them without losing more material.

After 21. Nc6 Be6 in your continuation of the 14. ..Qf6 line, Spike however evaluates the position at only +1.14 at a max. depth of 22 ply.

Worse, after <MostlyAverageJoe>'s continuation of your side line 18. ..Nc6 19. Bd1 Bf5 20. Re3 Rae8 21. Rfe1: ..Rxe3 22. Rxe3 Rf6 (I take that MostlyAverageJoe forgot to mention the rook exchange which is necessary before Rf6 and evident from the resulting position), there is

23. Ne5 (the only way for White to open the position and thus try to win) Nxe5 24. Rxe5 Ra6 25. g4 Be6 26. Bf3 Kf6 27. a4 Rxa4 28. Bxd5 Bxd5 29. Rxd5 Ra2 30. Rc5 b5 31. Rxb5 Rxc2 32. Rc5 (32. Ra5 Rxc3 33. Rxa7 Rd3) Rxc3 33. Kg2 with equality.

White may still have ways to force a win after 15. ..Qg7, e.g. playing Ne5 at an earlier point, but the one thing that is certain is that the win, if any, is much much less trivial to find than that after 14. ..Rxf7 as played in the game.

Jun-26-07  Topista: I thought that white should play 15.BXg6.
Does the pawn storm 14.f4 work -14...f5
15.Nxc4?
Jul-01-07  Crowaholic: <Topista: I thought that white should play 15.BXg6.> I had found 14. Nxf7 Rxf7 15. Bxg6, too (I accidentally wrote fxg6 though, oops. That makes no sense.) and it seems to win simply because 15. ..hxg6 is forced and then 16. Re8+ Rf8 17. Rfe1 Nc6 transposes into the text line.

As for 14. f4, I think Black would play ..cxd3 instead of ..f5, with no obvious refutation.

Jul-04-07  Topista: In fact 15.Bxg6 blows to a certain extent out the advantage because of 15....Qd7.White are stil better but it gets abit trickier if I'm correct 14.f4 cXD3 15.f5 seems interesting for white.
But one could check it with a comp.Pls do so for me.
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