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| Nov-01-09 | | randomsac: The final position is so nice. The black king is trapped and an impending pawn promotion will soon checkmate him. The black knight is too clumsy to defend. What a way to go. |
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| Nov-01-09 | | karnak64: Clever. |
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| Nov-01-09 | | johnlspouge: Sunday (Insane):
A Kosikov vs V Bezman, 1986 (50.?) White to play and win.
Material: Even. The Black Kh8 is stalemated and vulnerable to back-rank mate. The Black Rb7 pins Nb3 to Rb2, but White has several ways to relieve the pin with mate threats, e.g., at the cost of Pf7 (which is apparently doomed anyway): 50.Rg2 Rxf7 [else, Rg8#]. The salient feature of the position is that Rb7 is the only active Black piece, with the endangered and immobile Black Kh8 and Nf8 tied to the blockade of Pf7. White might be able to exploit the immobility to cost Black several tempi during promotion of Pa5. Candidates (50.): Rc2, Re2, Rf2
50.Rf2
(1) The Ng3 is immune:
50…Rxb3 51.Rg2 (threatening 52.Rg8#)
(1.1) 51…Ng6 52.Rxg6 hxg6 [Rb8 53.Rf6 wins] 52.f8=R#
(1.2) Black must therefore remove Rg2:
51…Rb1+ 52.Kf2 Rb2+ 53.Kf3 (threatening to approach the b-file) 53…Rxg2 54.Kxg2
The Black Kh8 is stalemated; and the Black Nf8 tied forever to shuttle between f8 and d7, e6, or g6 (or face f8=R#). The White Kg2 calmly strolls over to Pd6 to capture it on d6 or d5. If Black moves Pd6 to d4, to protect it with Nf8-d6, White triangulates his K to lose a tempo to capture Pd4 while the N is on f8. The White K then continues his stroll to capture Pa6 and win. (2) If Black does not play 50…Rxb3 or 50…Rb8, White exploits the immobility of Nf8 and the acknowledged burden of Rb7 with 51.Nd4 52.Nb4 53.Nxa6. 50…Rb8 51.Nd4
White has the threat 52.Rg2 if Rb8 moves off the 8-th rank and 53.Ne6 if Nf8 moves from f8. White can improve his K position to d5, then approach Rb8 and Pa6 (or play Ne6 if Black tries to cut off the c-file with …Rc8). In any case, with an extra White N in Variation (2), the Black immobility spells doom. I missed the drawing defense 50...Re7+. |
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| Nov-01-09 | | patzer2: Starting with 47...c3 48. Nxb3!, this game makes for a fascinating study in defending against invading passed pawns. After 47...c3 it looks like Black's passers are threatening to break through, but 48. Nxb3! with the threat of 48...Rxb3? 49. Rg2! defends nicely. And of course as <RV> and Rybka have indicated, after 50. Rf2! Re7+! = Black is able to defend against the white passers' invasion. |
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| Nov-01-09 | | Willem Wallekers: Let's call it a Friday puzzle starting at move 51 then. |
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| Nov-01-09 | | Rzep: Nice final position. Black knight can't give up f8 square (because of mate) and black king has no sqare to move.
I believe I've solved Sunday puzzle for the first time. But as I see most of you didn't have serious problems. Maybe the easiest Sunday puzzle ever? |
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| Nov-01-09 | | chessgolfer: As most did, I saw 50) Rf2 but could not get past the defending and drawish 50..Re7+. Given Black's back rank situation and the fact that the Knight is forever devoted to defending against the passed pawn on f7, Rxb3 seemed suicidal so I didn't give it much thought. Not sure if that's good news or bad news. Interesting to say the least. |
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Nov-01-09
 | | OBIT: <zanshin and others>: For those lamenting the fact that this position is drawn with best play (uh huh, and who here would find all this OTB), I think we can fix it by moving the Black pawn from d6 to d5. That gives us the following position:
click for larger viewAfter the key move 1. Rf2!, Black has two tries:
1...Rxb3 2. Rg2! Rb1+ (2...Ng6? 3. Rxg6) 3. Kf2 Rb2+ 4. Kg1 Rxg2+ 5. Kxg2 and wins as in the game - bring the king forward, carefully avoiding any knight forks that drop the f-pawn, and pick off the d-pawn and a-pawn. 1...Re7+ 2. Kd2 Re6 3. Rg2! Rg6 4. Rxg6 hxg6 5. Nc5 Kh7 6. Nxa6 Nd7 (or 6...Ne6 7. Nb4 Kxh6 8. Nxd5 Kg7 9. a6) 7. Nc7 Kxh6 8. Nxd5 Kg7 9. a6 and the pawn promotes. It's quite a nice endgame study, IMO. |
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| Nov-01-09 | | ComboKal: <dannygjk> re: <This is really a study, not a puzzle.> and <once> re: <I think it depends on what you define as a puzzle.>
The Random House Webster's dictionary defines the word puzzle as: <-n 1. a toy, GAME, or problem designed to amuse by presenting difficulties to be solved.> By that definition, I would think that EVERY chess game, along with every position that is presented to be solved, is a puzzle. Maybe the key word here is <"solved">. Sometimes, IMO, solving a chess problem is not finding the win or draw, but just finding a better position. |
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Nov-01-09
 | | chrisowen: White has tailor made attack and should protect the passed pawn by Rf2. Rook takes knight then Rg2 canvasses it. He again only has checks then white cashes in with a king march since the opposite number is hemmed in the corner. |
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| Nov-01-09 | | Eisenheim: this was a very easy week |
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| Nov-01-09 | | zanshin: <It's quite a nice endgame study, IMO.> <OBIT> I played through your first line. Your 2nd with Re7 was immediately not good for Black. Good job with the analysis. |
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Nov-01-09
 | | Jimfromprovidence: Since we have learned that 50 Rf2 Re7+ draws, how about another move 50 for white instead? I was thinking 50 Rc2!?, below, giving up the f pawn while seeing 51 Rc6. (Note that 50... Rxb3 in the below diagram is not playable because 51 Rc8 is a forced mate.) 
click for larger viewHowever, after my initial enthusiasm, with 50 Rc2 Rxf7 51 Rc6 Rf6 I reached a dead end. 
click for larger view |
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| Nov-01-09 | | Marmot PFL: This was not that hard to work out. Black is threatening Rxf7 so Rf2 is the only winning try. Rxb3 now Rg2 threatening mate and black has to force the rook trade. Now is there any way to free the black pieces? It seems not and otherwise white just uses his king to take the d and a pawns winning easily. |
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| Nov-01-09 | | RandomVisitor: Final post: after 50.Rf2 Re7+ :
1: Alexey I Kosikov - Vadim Bezman, Soviet Union 1986
click for larger viewAnalysis by Rybka 3 : <30-ply> <1. = (0.19): 51.Kd2> Re6 52.Rh2 Rf6 53.Rh4 Nd7 54.Ke2 Rxf7 55.Rc4 Kg8 56.Rc6 Rf6 57.Rxa6 Rxh6 58.Nd4 <2. = (0.19): 51.Kd1> Re6 52.Rg2 Rg6 53.Rh2 Rf6 54.Rh4 Nd7 55.Rg4 Rf1+ 56.Ke2 Rxf7 57.Rc4 Kg8 58.Rc6 Rf6 59.Rxa6 Rxh6 60.Nd4 <3. = (0.18): 51.Re2> Rxf7 52.Re8 Kg8 53.Ra8 Rf6 54.Rxa6 Rxh6 55.Rb6 Ne6 56.Rxd6 Kf7 57.Rd7+ Ke8 58.Rb7 Nd8 59.Rb5 Kd7 60.Kf2 Kc7 61.Kg3 Nb7 62.Re5 Nd6 63.Kg4 Rg6+ 64.Kf3 Rh6 65.Re7+ Kc6 66.Nd4+ 4. = (0.05): 51.Kf1 Re6 52.Rc2 Rxh6 53.Rc6 Kg7 54.Rxa6 Kxf7 55.Rc6 Ne6 56.Rxd6 Rh2 57.Rd7+ Ke8 58.Rd5 Ra2 59.Ke1 Nf4 60.Rd4 Ne6 61.Rh4 Ra3 62.Rh6 Nd8 63.Nd4 Rxa5 64.Ke2 Nf7 |
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| Nov-01-09 | | agb2002: Material is even. Black threatens 50... Rxf7. If both rooks and the white knight disappeared White would win by capturing Black's d pawn and then the a pawn because the black knight could only cycle between f8 and d7 or g6. The only detail to take into account is to place the king on c8 just before crowning in case the black knight is on f8 to avoid the stalemate. This suggests 50.Rf2, threatening Nd4 - Ne6 Nxe6 - f8=Q+ Nxf8 - Rxf8#: A) 50... Rxb3 51.Rg2 (threatens 52.Rg8#) Rb1+ (51... Ng6 52.Rxg6 Rb8 53.Re6 + -) 52.Kf2 Rb2+ 53.Kf3 Rxg2 54.Kxg2 + -. B) 50... Re7+ 51.Kd2
B.1) 51... Re5 52.Rg2 Ng6 53.Rxg6 + -.
B.2) 51... Rc7 52.Nd4 Re7 53.Kd3 Rc7 54.Ne6 Rc8 55.Nxf8 Rxf8 56.Kd4 + -, the White king will capture Black's queenside pawns. C) 50... Rc7 51.Nd4
C.1) 51... Re7+ 52.Kd2 transposes to B.2.
C.2) 51... Rc8 52.Kd2 and the king will invade Black's position because the rook cannot leave the back rank and the knight cannot move from f8 because of Ne6. I don't have the time today for a deeper analysis but I have the impression that this is the essential of the position. |
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| Nov-01-09 | | MaczynskiPratten: Many of the positions this week have brought a smile to my face. Many have been counter-intuitive. The idea of White deliberately letting his only two pieces be taken or exchanged and going into an ending a piece down - amazing! And the final zugzwang position - who would have thought that a knight and pawn could be so helpless against a lone king? As pointed out previously, the heroes are White's f7 and h6 pawns which tie up Black's king single-handed. It looks like a composed study, but it's real! |
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| Nov-01-09 | | wals: Ah I see now why 50.Rf2..
Alexey I Kosikov - Vadim Bezman, Soviet Union 1986
Analysis by Rybka 3 1-cpu: Ply 24 time 16 min 18 sec 1.  (0.72): 50.Rc2 Rxf7 51.Rc6 Ra7 52.Kf2 Kg8 53.Rxd6 Nd7 54.Ke3 Kf7 55.Kf4 Ke7 56.Rc6 Rb7 2.  (0.40): 50.Re2 Rxf7 51.Re8 Kg8 52.Ra8 Rf3 53.Nd4 Rf4[] 54.Nc6 Kf7[] 55.Rxa6 Nd7 56.Ra7 Ke6 57.Rb7 Rc4[] 58.Nd8+ Ke7[] 59.Nf7 Ra4[] 60.Ra7 Kxf7[] 61.Rxd7+ Ke6 62.Ra7 Ra2[] 63.Kd1 Kf6[] 64.Kc1 Kg6 65.Kb1 |
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| Nov-01-09 | | wals: 50....Rxb3 was a blunder |
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| Nov-01-09 | | David2009: Sunday's insane puzzle A Kosikov vs V Bezman, 1986 White 50? It is 9 PM local time and I have just started this puzzle, I need to wrap it up quickly if at all.
My first thought is 50 Rf2!? Rxb3 and the intended Rg2?? loses to Rb8+ exchanging Rooks and winning.
Back to the drawing-board: 50 Rf2!? Rxb3 51 Kf1!? Rb1+ 52 Kg2 Rb7 and Black is more mobile than White, so this fails as a
winning attempt. WAIT! 51 Rf6 and Black's King side is tied up. Moreover White can play Rxd6 with impunity unless Black is threatening the f7 Pawn This must be it. 50 Rf2 Rxb3 51 Rf6 and the ball is in Black's court. Time to
check:
=====
I missed the game continuation - White can afford to exchange Rooks!! Truly bizarre; truly elegant; truly INSANE! Crafty check: http://www.chessvideos.tv/endgame-t...
My line 51 Rf6 LOSES: 51...Rd3 (threatening Rd5 and taking the a pawn) 52 Rf5 Rg3 53 Rf6 (hoping for repetition) Rg6! 0-1
"The blunders are all there, waiting to be made" - Tartakower. 
click for larger view Kosikov-Bezman 50? Crafty loses to the game line 50 Rf2 Rxb3 51 Rg2 Rb1+ 52 Kf2 Rb2+ 53 Kg1 Rxg2+ 54 Kxg2, varying at move 54: 54...d5 55 Kf3 d4 56 Ke4 e3 57 Kxe3 Ne6 58 Kc4
Nf8 59 Kd5 Ne6 60 Kd6 Nf8 61 Kc7 Nd7 62 Kb7 Nc5+ 63 Kxa6 and wins. White only has to avoid variations losing the f7 or h6 Pawn to a N fork. |
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| Nov-01-09 | | remolino: This problem is insane indeed because as Rybka points out (thanks to wals) the right answer is 50.Rc2. Then Black, after taking on f7, must defend the a pawn, yet white keeps a more active position. This is the solution - best play for both sides - no one got the answer today! Like many of you, I got the line with 50.Rf7 sacrifizing knight and exchanging rooks, reaching a won king vs knight ending. Others went further than me and recognized that 50...Re7+ drew for Black. But none gave 50.Rc2 as the winning line with good variations to support that answer. Amazing. Insane. Wonder what Kasparov or Topalov would have done OTB. |
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| Nov-01-09 | | WhiteRook48: I tried 50 Rg2 |
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| Nov-01-09 | | Criswell: Ok..I look at this position and the immediate 50. Rg2! shouts to me saying "Hey look I threaten mate!" so 50. Rg2 it is! -------------------
50. Rf2. Interesting move but I fail to see why it is superior to Rg2. Anyone care to point me in the right direction? |
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| Nov-01-09 | | dannygjk: My computer prefers 50.Rc2 but seems to lead to a draw. As with most of the humans I liked 50.Rf2 but 50...Re7+ seems to equalize. |
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Nov-01-09
| | OBIT: <remolino>50. Rf2 is correct because very few human chessplayers would never see that the only drawing line is that Re7+ followed by Re6 thing. Your stupid computer has a lot to learn about human behavior. |
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Kibitzing
sac: 50.Rf2