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| Mar-28-09 | | butilikefur: 19...Nb4 20. axb4 axb4 21. Bxb4 Ra1+ 22. Ndb1 Qb6 23. Ba3 Nxa3 24. bxa3 (24. Kd2 Nc4+ 25. Ke2 Nxb2) 24...Bxc3 25. Qxc3 Rxb1+ 26. Kd2 Qf2+ 27. Kd3 Rxd1+ 28. Rxd1 Bd7 and now there are probably more ideas than what I found.. 29. Qa5 b6 (not 29...Qxg2 30. Qd8+ Rf8 31. Qxd7 Qe4+ 32. Kd2 e5 and black is better but has a difficult game ahead) 30. Qd2 Bb5+ 31. c4 Bxc4+ 32. Kc3 Qc5 33. Kb2 Ra7 34. Qc3 Ra5 wins (for example, 35. Rd2 Rb5+ 36. Kc1 Rb3 37. Qc2 Qxa6+ 38. Kd1 Qa1+ 39. Qc1 Rb1 40. Rc2 Qd4+ 41. Ke1 [42. Rd2 Qg1+ 43. Kc2 Qxc1+ mate] 41...Qe3+ 42. Kd1 Rxc1+ 43. Rxc1 Qe2+ mate) |
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Mar-28-09
 | | Once: <patzer2: After 19...Nxb2 20. Kxb2 b3 21. Bg1 (with "silicon hindsight"), Black seems to have nothing better than 21...Nb4 22. Qf3 Bb7> I'm not so sure. Of course, 19...Nb4 is the cleaner line, but there is more to 19...Nxb2 than meets the eye. The point is that the pin on the Nc3 is hard for white to evade. Black threatens to win back the piece and remain a safe pawn up. So instead of your 21. Nb4, surely we want to pile up on the pinned piece with something like this line: 19... Nxb2 20. Kxb2 b6 21. Bg1 Ba6 22. Qf3 Na7 23. Ndb1 Nb5 
click for larger viewBlack threatens Rc8 with even more pressure on the Nc3. Fritzie says -1.4, which seems about right to me. <SgtPepper> Thankfully, this is chess and not sudoku, which means that there is more than one "right" answer. My engine (Fritz 11) is saying that 19...Nxb2 is fully playable and leads to a black advantage. It may not be as decisive as 19...Nb4, but that's not always the point. Saturdays and Sundays are often as much about the discoveries that we make in some of the interesting side variations. |
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| Mar-28-09 | | johnlspouge: The variation <patzer2> gives: < [snip] 19...Nb4! 20. axb4 axb4 21. Bxb4 Ra1+ 22. Ndb1 Qb6!
[snip] >
is critical. In all other variations after 19...Nb4, Black achieves material equality very rapidly, with an obvious positional improvement. Today's puzzle is therefore straightforward, if you are attracted to this one variation. If not, the multiplicity of plausible candidates makes the puzzle quite obscure. (A player presently rated 2575 missed the best move.) |
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| Mar-28-09 | | patzer2: <Once> Your Fritz 11 analysis of 19...Nxb2 20. Kxb2 b6 21. Bg1 Ba6 22. Qf3 Na7 23. Ndb1 Nb5  to  is convincing. White's position with the piling on of the pinned Knight is certainly tenuous, and if the position's not already a win for Black it's mighty close.This is indeed an interesting and instructive discovery in today's Saturday's puzzle. Thanks! |
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| Mar-28-09 | | Geronimo: I looked at Nxb2 and the text b5 for about 10 minutes before deciding it must be one of those two. This is a bit overdetermined, as there seem to be winning lines for black all over. I didn't even consider Nb4! |
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| Mar-28-09 | | Utopian2020: 19... Nb4 looks best when white takes the bait and follows with 20. axb4 axb4 21. Bxb4 Ra1+. But white's position is better with 20. Qe2 20. Qxc5 21. Nxc4. In the game line, black got lucky white played 20. b3 instead of 20. Nxc4. White's chances were good, if white had played 19. Rhe1, and we would have had a different puzzle for today. |
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| Mar-28-09 | | WhiteRook48: I missed the Saturday puzzle |
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| Mar-28-09 | | dzechiel: Black to move (19...?). Material even. "Very Difficult." Getting a late start as I fell asleep last night before 9:00p PDT (when the position of the day shows up in California). I'm a little pressed for time this morning, so I'm just going to run with what I first see. It seems to me that the key element of this position is the a-file. White has castled to the queen's side, and now black can try moves like 19...Nb4
This move isn't too difficult to find, as it both attacks the white queen and the white bishop on c5. White can't simply move the queen without losing the bishop, so I think it will follow 20 axb4 axb4
This is where white has to make a decision. The black rook is threatening check on a1, the white knight is under attack by the pawn, and b2 is very weak. 21 Bxb4
White does have other tries, such as 21 Nxc4, but the knight on c3 cannot move (21 Nb1 Bxb2#). 21...Ra1+ 22 Ndb1
OK, I give up. I don't see how black makes progress here. =====
Wow, totally on the wrong track. I'm tempted to not post this at all... <sigh> |
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| Mar-28-09 | | RandomVisitor: 19...Nxb2 20. Kxb2 b6
click for larger view Rybka3:
[-1.01] d=15 21.Bd6 Qxd6 22.Nde4 Qe7 23.Nxf6+ Qxf6
[-1.41] d=15 21.Bf2 Ba6 22.Qe3
[-1.61] d=14 21.Bg1 Nb4 22.Qf3 Bb7 23.axb4 axb4 24.Kc1 |
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| Mar-28-09 | | dzechiel: OK, now that I have read the kibitzing I feel somewhat better. I should have stayed with it, but time doesn't permit. |
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| Mar-28-09 | | PhilFeeley: Straight line between the black queen and the white king - if there weren't a few other pieces in the way. |
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Mar-28-09
 | | Jimfromprovidence: In the line 19...Nb4! 20. axb4 axb4 21. Bxb4 isn't 21 Bd4 a bit better for White?
click for larger view |
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| Mar-28-09 | | CHESSTTCAMPS: Material is even and both sides are actively developed, with the exception of black's bishop on c8. However, black is more effectively deployed with an obvious queen-side initiative. The Nc4 and Bf6 coordinate to create a grip on the a1-h8 diagonal and the pawn on a5 offers prospects for a quick opening of the a-file. In a complex tactical setting such as this, there are a number of plausible candidates for black's move 19, including (1) Na7 (2) Ne7 (3) N6e5 (4) Bxf3 (5) b6 (6) Nb4 and (7) Nxb2. My attention was immediately drawn to Nxb2 because it takes out the linchpin of the white king's defensive pawn structure and increases the value of black's Bf6 by pinning the Nc3. Moves such as b6 or Nb4 might be used to prepare this move, but the most forcing move merits primary consideration. Analysis of Candidate (7):
19... Nxb2
20.Kxb2 b6!
Removes the bishop from defense of b4 and opens lines for the Rf7 and the Bc8. Now: A. 21.Bf2 Nb4! 22.axb4 axb4 23.Nb3 Bxc3+ 24.Kc1 (or Kb1) Qh7 25.Qxc3 (otherwise 25..Qa1+) bxc3 and white can't defend Qa2+ followed by Qa1+ A.a 23.Nb1 Bxc3+ 24.Nxc3 bxc3+ 25.Kb1 (Qxc3 Ra2+ 26.Kxa2 Qxc3 and the threat of Ra7+ is decisive) Ra1+! 26.Kxa1 Qa7+ 27.Kb1 Qa3 and white can resign A.a.a 25.Kb3 Ba6 26.Qe3 Qc4+ 27.Ka3 Bb7+ and mate next. A.a.b 24.Kc1 Ra1 25.Rdf1 Qa7 (threatening Rxb1+) 26.Kd1 Rxb1+ 27.Ke2 Ba6 wins easily. A.b 22.Qf3 (Qe3 d4 wins quickly) Bb7 and the threat of d4 looks overwhelming. There are more lines to examine, but I believe that Nxb2 is the right continuation. |
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| Mar-28-09 | | CHESSTTCAMPS: Wow, among my 7 candidates, I didn't even consider the game continuation, but I see that there is both kibitzer and computer support for the line I selected. |
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| Mar-28-09 | | SamAtoms1980: Hmmm. I looked at five or six different candidate moves before settling on 19 ... d4. 19 ... Nb4 I gave a close examination, 19 ... b5 I didn't see at all. At any rate, my streak of made puzzles is stopped at six. This position was simply too complex for me to have a chance. |
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| Mar-28-09 | | CHESSTTCAMPS: <Jimfromprovidence:> wrote <In the line 19...Nb4! 20. axb4 axb4 21. Bxb4 isn't 21 Bd4 a bit better for White?> I was about to post giving you my support, then I noticed 21...Nxb2! 22.Kxb2 bxc3+ 23.Bxc3 Bxc3+ 24.Qxc3 Ra2+! 25.Kb3 Ra3+ winning the queen, similar to one of the lines in my initial post. |
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| Mar-28-09 | | sandmanbrig: I really dont see how white can get an advantage with a move like 7. Qe2. It just seems to keep the light squared bishop out of the game |
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| Mar-28-09 | | goodevans: <CHESSTTCAMPS: <Jimfromprovidence:> wrote <In the line 19...Nb4! 20. axb4 axb4 21. Bxb4 isn't 21 Bd4 a bit better for White?> I was about to post giving you my support, then I noticed 21...Nxb2! 22.Kxb2 bxc3+ 23.Bxc3 Bxc3+ 24.Qxc3 Ra2+! 25.Kb3 Ra3+ winning the queen, similar to one of the lines in my initial post.> But what if 23 Qxc3? Is it 23 ... Bxd4 24 Qxd4 Qa5? |
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| Mar-28-09 | | TrollKing: This was a poor puzzle. Rybka evaluates the game continuation,
19... b5 as almost dead even, but
19... Nb4 at roughly -1.20. A
little better for Black, but nothing
decisive. White simply played
poorly. |
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| Mar-28-09 | | patzer2: <Jimfromprovidence> After 21. Bd4, Black seems to have the win well in hand after 21...Bxd4 22. Qxd4 bxc3 23. Qxc3 d4 24. Qd3 Ne3 25. Be4 e5 26.
Bxh7+ Kh8 27. Rde1 Ra1+ 28. Nb1 Be6 29. b3 Qa5 30. Be4 Rf8 31. Rxe3 dxe3 . |
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| Mar-28-09 | | patzer2: <RV> thanks for the analysis of 19...Nxb2 20. Kxb2 b6 21. Bd6 . I'd think that with the extra pawn and better
pawn structure (two isolated White pawns to target), Black has excellent endgame changes, despite Rybka's somewhat optimistic evaluation of only a -1.01 advantge for Black. However, its enough to illustrate that 19. Nb4! is the stronger winning try.
By the way, I wonder what your Rybka 3 analysis shows as the numeric assessment for 19. Nb4! |
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| Mar-28-09 | | CHESSTTCAMPS: <goodevans:> wrote <[snip] But what if 23 Qxc3? Is it 23 ... Bxd4 24 Qxd4 Qa5?> You are right - 23.Qxc3 should hold in the line I suggested. In fact, the "similar" tactics in my initial post involved a different position. However, the last post from <patzer2> seems to make a good case against 21.Bd4 in the 19....Nb4 line. |
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| Mar-28-09 | | whiteshark: 19...Nb4, intuitively. None taken. |
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| Mar-29-09 | | TheBish: D Ciuksyte vs V Golod, 2003 Black to play (19...?) "Very Difficult" (3.5 stars)
Material is even, but Black is better because he has the attack on White's king and the move. Candidate moves: Nxb2, Nb4, b6.
I was originally looking at 19...b6 20. Bf2 Nxb2 21. Kxb2 Ba6 22. Qf3 Nb4 followed by 23...Rc8, but that's a very speculative sacrifice, and not sure if it works. I found a move I like better though. 19...Nb4! This forces open the a-file for Black's advantage. 20. axb4 (or 20. Bxb4 axb4 21. axb4 Ra1+ 22. Ndb1 Qb6! and Black has a winning attack, since 23. b5 Qxb5! 24. Nxb5?? Bxb2#) axb4 21. Bxb4 Ra1+ 22. Ndb1 (or 22. Ncb1?? Bxb2#) Qb6! 23. Ba3 Nxa3 24. bxa3 Rxb1+ 25. Kd2 Qf2+ 26. Kd3 Rxd1+ 27. Rxd1 Bd7 and Black appears to be winning with the dual threats of 28...Bb5+ and 28...Qxg2. Very complicated position, where Black may have more than one winning move. Let's see how it played out. |
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| Mar-29-09 | | Eduardo Leon: 19. ... Nb4!
White can choose one of the following options:
a. Lose the c5 bishop.
b. Capture the knight and be mated soon. |
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