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|Apr-15-10|| ||TheBish: Boleslavsky vs Bronstein, 1950|
White to play (50.?) "Medium"
I found this one to be easier than "medium". But only because I avoided the traps! Not 50. dxe6? Bxg6+! 51. Kxg6 (or 51. Nxg6 b3 and Black's pawn queens) Ke7! 52. Nd7 b3 and the pawn can only be caught by 53. Nf6! b2 54. Nd5+ Kxe6 55. Nc3, but subsequent analysis by Fritz shows that Black wins this by advancing the c-pawn and king. Also, 50. Nxe6+? Ke7 51. g7 Bh7! 52. Nd4 Kd6 and Black should draw.
50. g7! is the way to go. Black's best is 50...Be2+ 51. Kg5 Re4 (or Re3 52. g4) 52. Kf5 Rg4 53. Ng6! and the pawn will queen after 53...Rxg6+ 54. Kxg6 Bd3+ 55. Kh6! - but not 55. Kf7?? Bh7! and Black wins! This last note just shows that you can never let up until the game is won!
|Apr-15-10|| ||agb2002: White has a knight and a pawn for a rook and bishop.|
Black threatens 50... Bxg6+ 51.Nxg6 Rxg6 52.Kxg6 b3 winning.
The natural 50.Nxe6+ looks problematic after 50... Ke7 (50... Kd7 51.Nc5+) 51.g7 (51.Nxc7 b3) Bh7 52.Nd4 Kf7 53.Kh7 Be4 and Black moves the bishop along the b1-h7 diagonal.
The obvious 50.dxe6 seems to fail after 50... Bxg6+ (50... b3 51.g7 b2 52.g8=Q b1=Q 53.Ng6#) 51.Kxg6 (51.Nxg6 b3 52.Ne5(f4) b2 - +)
A) 51... b3 52.Kf7 b2 53.e7+ Kc8 54.e8=Q+ Kb7 55.Qb5+ and 56.Qxb2 + -.
B) 51... Ke8 52.Nd7 b3 (otherwise 53.Nc5) 53.Nf6+ Ke7 54.Ne4 b2 55.Nc3 Kxe6 56.g4 Ke5 (56... Ke7 57.Kg7) 57.g5 Kd4 58.Nb1 Kd3 59.Kf6 Kc2 60.Na3+ Kc1 61.g6 b1=Q (61... c5 62.g7 c4 63.g8=Q c3 64.Qg6 + -) 62.Nxb1 Kxb1 63.g7 c5 64.g8=Q c4 65.Qxc4+, etc.
C) 51... Ke7 52.Kf5 b3 53.Ng6+ Ke8 54.Ne5(f4) b2 - +.
A) 50... Re5+ 51.Kh6 b3 52.g8=Q b2 53.Ne6+ Ke7 (53... Kd7 54.Qd8#) 54.Qf8+ Kd7 55.Qd8#.
B) 50... Bh7 51.Nxh7 Re8 (51... Re5+ 52.Kh6) 52.Nf8 b3 53.g8=Q b2 54.Qg7 Re7 55.Qxb2 + -.
C) 50... Be2+ 51.g4 Re5+ 52.Kh6 is similar to A.
|Apr-15-10|| ||johnlspouge: Thursday (Medium)
Boleslavsky vs Bronstein, 1950 (50.?)
White to play and win.
Material: N+P for R+B, but White can recapture a R with 50.dxe6 or 50.Nxe6. The Black Kd8 has 3 legal moves. The Black Pb4 and White Pg6 are immediate candidates for queening. The White Kh5 is vulnerable to Re6-e5+, and checks from Bd3.
Candidates (50.): g7
50.g7 (threatening 51.g8=Q, when White has Q+N for R+B)
The gain of Q for P is the biggest threat on the board, with the exception of check or mate, so Black must lift the threat, check, or threaten mate.
50…Be2+ [Re5+ 51.Kh6, and Black has only spite checks]
51.Kg5 (threatening 52.g8=Q or 52.Kf6 53.Ng6)
The second threat avoids a skewer on the g-file and enforces g8=Q.
Black cannot stop both threats.
|Apr-15-10|| ||azax: This wasn't too difficult for a Thursday. The obvious 50. Nxe6+ Ke7 51. Kh6 seems to guarantee promotion and a win for white, but after 52. ...Bxg6! 53. Kxg6??, Black's b-pawn rushes to the end of the board and queens. After 53. Nd4, Black has gained the pawn for free and the pressure is suddenly on white to stop this menace from taking control of the game (by marching his king in to take it, while black can munch up his other pawns). Much cleaner is 50. g7!, with the threat of promotion and no good defense against it.|
|Apr-15-10|| ||desiobu: I didn't even notice black's b-pawn. Without I guess the position is trivial though.|
|Apr-15-10|| ||tatarch: <Jimfromprovidence: 50 g7 looks real straightforward, but there are some traps. For example, here is the position after the plausible continuation 50...Be2+ 51 g4 Bxg4+, below... Here, white cannot play 52 Kxg4 because of the skewering set up move 52...Re1!>|
Thanks for pointing that out, I hadn't considered the line but the skewer set up is instructive.
|Apr-15-10|| ||jimmyjimmy: I would definitely capture the rook with the knight in a heartbeat! It just doen't make sense to me to pass that up at any cost.|
|Apr-15-10|| ||Marmot PFL: More complicated than it seems at first - Bronstein misses a possible draw with 53...Bb5 54 g8(Q)+ Be8 with Rxg6 to follow.|
|Apr-15-10|| ||kevin86: Here is the rare case in which the reflex recapture is not the solution. White sets up a breakaway pawn.|
|Apr-15-10|| ||chrisowen: Promote a pawn trooper 50.g7. Ha why he turfs the soldier along, hello then misses Kf5! is criminal ..Re4 Kf6? Rg4 Ng6 Bb5! Casting the eye over broad intentions I suppose a big waive his rights? Yet it lands him in hot water. The theme is white fights on grounds patrolling of course g7, blacks general aim is to shoot Bronstein outta the sky ..rxg6+ Kxg6 Bd3+ Kh6 restores law and order.|
|Apr-15-10|| ||benveniste: I got b7, but I made the same mistake Boleslavsky did with 52. f6. Fortunately for him Bronstein didn't have a computer to find 53. ...b5!|
|Apr-15-10|| ||Jack Kerouac: Check this out http://pbfcomics.com/?cid=PBF093-Ch... |
|Apr-15-10|| ||atakantmac: why not 50.dxe6?|
|Apr-15-10|| ||YouRang: It was a choice between taking the rook, or pushing the pawn.|
All variations of taking the rook seemed to either jeopardize my ability to promote the pawn, or worse, created the prospect that black would promote first.
But for the life of me, I couldn't see how black could stop me from turning my g-pawn to a queen (and I did consider the Rg4 skewer, which is blocked by the knight).
Beyond this analysis, it's a no-brainer.
|Apr-15-10|| ||ajk68: <TheBish>:
<I found this one to be easier than "medium". But only because I avoided the traps! Not 50. dxe6? Bxg6+! 51. Kxg6 (or 51. Nxg6 b3 and Black's pawn queens) Ke7! 52. Nd7 b3 and the pawn can only be caught by 53. Nf6! b2 54. Nd5+ Kxe6 55. Nc3, but subsequent analysis by Fritz shows that Black wins this by advancing the c-pawn and king.>
It is a win in 47 according to the tablebase. There are many drawing chances if black doesn't make several non-intuitive moves. There are also ways to lose for black (and in fewer moves) from this position. I'm not sure a grandmaster could accurately see all this.
50.dxe6 is a very good defensive choice. Black would have a hard time winning.
|Apr-15-10|| ||scormus: Easy for a Thursday? Hmm I'm not so sure. Took me a while to satisfy myself that taking the BR was not right, but even after 50 g7 there are ways W can go wrong. I didn't see all of B's possible defenses (and I certainly didn't pick up on the Bb5 and Be8 save). But I did prefer 52. Kf5 over Kf6 <Benveniste, chrisowen>|
|Apr-15-10|| ||mworld: i fell for the trap of taking the rook...beautiful puzzle; i like that it required us to see black's defensive options, too bad i missed one of them.|
|Apr-15-10|| ||MaartenSmit: 50. Nxe6+ gives 50. ..., Ke7
Which can continue as:
51. Nc5, Bc4
52. g7, Bxd5
53. Kh6, b3
54. Nxb3, Bxb3,
55. Kh7, c6
56. g8D, Bxg8
51. Nd4, Kd6
52. Kh6, Bxg6
53. Kxg6, Kxd5
54. Nb3, Kc4
52. g4, Kxd5
53. Kh6, Bxg6
54. Kxg6, Kxd4
Thus, white can't win after 50. Nxe6+.
|Apr-15-10|| ||mworld: to clarify, it was dxe6 that was the one i fell for...didn't realize black had a counter to it involving the bishop sac.|
|Apr-15-10|| ||BOSTER: Looking at the position on diagram you have clearly understand that the main star is the pawn g6 , and only one move which leads to possible forced win is 50.g7.
When I read <dzechiel> comment, where he made couple steps in "wrong" direction, my opinion this is the wrong attitude to decide the puzzle , because moves like 50.Nxe6 or 50.dxe6 looks like the bait.|
|Apr-15-10|| ||wals: Rybka 3 1-cpu : 3071 mb hash : depth 16:
Things started to go awry in the end game:-
+1.05 44...Rb3 v Bc4 +1.00
+4.72 47...b4 v Rd4 +3.28
+0.18 52.Kf6 v Kf5 +9.46
+9.13 53...Rxg6 v Bb5 +0.19
|Apr-15-10|| ||rapidcitychess: Alright, this was pretty easy, 50.g7, right?|
|Apr-15-10|| ||randomsac: At first, I wondered why capturing the rook wasn't the answer (since it was too obvious). Then I realized that pushing the pawn allows it to promote with careful play. Cool puzzle.|
|Apr-15-10|| ||A Karpov Fan: got it|
|Apr-16-10|| ||chrisowen: <scormus benveniste> Often it is best to be sure, eating the rook serves up a draw. 50.g7, the king then followed the knight Kg5 Kf6 guarded the pawn...veni vidi vici. Late in, vi now Kf5 does cover it as the true place of the bishop is b5. Rook is free for a rum time swallowing the knight shark. So upon our tale Kf5 is the ideal finish.|
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