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| Aug-01-08 | | johnlspouge: Friday (Difficult): White to play and win.
Material: Even. White has superiority in space and control of the e-file with a battery Re1 and Re6. The White Qf5 can penetrate the Black K-side. Candidates (36.): Rxf6
36.Rxf6 (threatening 37.Qg5+ 38.R1e6)
Black has 2 choices to recapture, to avoid outright loss of a P in an inferior position: (1) 36…Kxf6 37.Qh6+ Kxf5 38.Re6 (threatening 39.Qf4#) A few times in the following, a winning Q vs. R endgame could result from the Q capture (1.1) 39…Qxe6 40.Qxe6+ Kg5 41.Qxf7
Thus,
(1.2) 39…Kg4 40.Kg2 (threatening 40.Qh4+ Kf5 41.Qf4#) 40…Rf2+ 41.Kxf2 Qf7+ 42.Rf6
and Black is finished.
(2) 36…Rxf6 37.Qg5+
Black has 2 options to avoid the loss resulting from abandoning Rf6: (2.1) 37…Rg6 38.fxg6 (threatening 39.Re7+ and 39.gxh7+) 38…Re8 [Kf8 39.gxh7] 39.gxh7+ Kxh7 40.Qh5+ (forking Re8). (2.2) 37…Kf7 38.Re6 (threatening 39.Rxf6+ and mate soon) 38…Qxe6 [Rxe6 39.fxe6+ forks Qd7) 39.exf6+ Ke7 40.Qg7+ wins Rf6. |
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| Aug-01-08 | | JohnBoy: The real issue is the line found by <Jimfromprovidence> above. In the final, posted position white cannot hold both pawns. If the rooks come off, the resulting Q+P ending is probably won, but likely with much effort. I'd like to see the results of an engine's analysis of that final, posted, position. |
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| Aug-01-08 | | sexymichelle7: I solved today`s chess puzzle in 2minutes-not bad for a Beverly Hills blonde:) |
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| Aug-01-08 | | 456: Thursday puzzle Jul-31-08 <31. ?< Ivanchuk vs Anand, 1994 |
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| Aug-01-08 | | johnlspouge: <<JohnBoy> wrote: The real issue is the line found by <Jimfromprovidence> above. [snip]> White does not need to hold both Ps to win. The simplest win from the diagram <Jimfromprovidence> gives is 40.Rxe8+ Qxe8 41.Qg8+ Qxg8 42.hxg8=Q+ Kxg8
click for larger viewgoing into a straightforward K+P endgame win for White. White shepherds Pg3 with Kg1 to achieve the following position with White to move: 
click for larger viewand then mops up the base of the opposing P chain with the K. |
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Aug-01-08
 | | benveniste: <dzechiel>On, 36...Kh8 37 Rxf7 Qxf7 38 f6 Re8 39 Rxe8+ Qxe8 40 f7?, black draws with Qe1+. White needs to be a bit more patient, for example by bringing up the king and g-pawn. |
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Aug-01-08
 | | al wazir: <gandu: after 36. Rxf6 Re8 37. Rfe6 Ref8 38. f6+ Kh8 39. Re7 Qd8 40. Qh6> Kg8. I see no toast here. |
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Aug-01-08
 | | Jimfromprovidence: I quit on my line too early.
I proposed 36 Rxf6 Rxf6 37 Qg5 Rg6 38 fxg6 Re8 (which prevents the rook skewer on e7) 39 gxh7+ Kh8, and which wins a couple of pawns for white. But, as <johnlspouge> astutely pointed out, continuing with 40.Rxe8+ Qxe8 41.Qg8+ Qxg8 42.hxg8=Q+ Kxg8 wins easily for white.
click for larger viewSo, after 36 Rxf6, does black really have a viable defense? |
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| Aug-01-08 | | randallbsmith: It would be helpful to me (and possibly others at or below my level) for someone of the many of you who instantly saw 36. Rxf6 to explain what about this position suggests such a silly looking move. I mean, now that I see it, sure it obviously is a good one, but my brain wouldn't even allow me to go there, as it appears to immediately throw away my rook. For example, was it the observation the the f6 pawn was preventing the queen's access to g5? Or? I wanted to get material over to the right side, which looks vulnerable as black is all clogged up in the upper left, but couldn't see a winner as to how to pull it off, and it is true that the rXf6 does help that. Was that it? Or...? |
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| Aug-01-08 | | Schach and Awe: Snapshot View
Black on the defensive, with isolated pawns in the h and f files, and a weak backward pawn in the d file. My inclination is to shift the focus to the h file, get the Queen to h6. I made a number of tries playing White against Rybka, but came up well short of a decisive advantage. Weaknesses are only that when they can be exploited. I have to admit I was more than a bit surprised at the move played. |
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| Aug-01-08 | | MorphyMatt: Hah! Got it in 3 seconds. Difficult?? |
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Aug-01-08
 | | Once: <randallbsmith> Some "stream of conscious" stuff here: White has a great position. He has control of the only open file, advanced pawns, an active queen and the black king is much more vulnerable than the white counterpart. But black is holding on. Every piece and pawn is adequately defended (barring tactics) and the black king does not seem to be in immediate danger. He can always scurry off to f8 or gh8 if attacked. In a real game, I would look for ways to increase white's pressure. Can I triple heavy pieces on the e file? Or double up on one of black's weak pawns? This would be a relatively safe way to make progress, as it would not cost me anything. Because we have a dominant position, it is also worth looking for what Purdy called "moves that smite". Until we look at these moves, we don't know whether they will work or not, but our positional superiority gives us ammunition for a follow-up. In other words, when you have a positional superiority, it is worth taking a little time to look at moves that might otherwise be silly. Rxf6 is just one of a number of moves worth considering. It allows Qg5+ without removing the control of the e file. It takes a piece away from the defence of the black king. So we ask the question "I wonder what happens if ..." I guess that most kibitzers on this site also looked at moves like Rxd6 and Re8 (but they didn't mention them in their posts because they lead nowehere). When a position looks juicy, give every violent move a little consideration - it might just lead to a tactic. |
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| Aug-01-08 | | kevin86: A brilliant move by white; by lendind his rook, he could penetrate the opponent's soft underbelly. |
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| Aug-01-08 | | zooter: <johnlspouge: <<JohnBoy> wrote: The real issue is the line found by <Jimfromprovidence> above. [snip]> White does not need to hold both Ps to win. The simplest win from the diagram <Jimfromprovidence> gives is 40.Rxe8+ Qxe8 41.Qg8+ Qxg8 42.hxg8=Q+ Kxg8
going into a straightforward K+P endgame win for White. White shepherds Pg3 with Kg1> This seems an easy win, but Crafty 22 gives
17 +3.25 40. Re6 Qf7 41. Rf6 Qe7 42. Qf5 Qe1+ 43. Kh2 Qe5 44. Qxe5 Rxe5 45. Rxd6 Re2+ 46. Kh3 Kxh7 47. Rc6 Rxa2 48. Rxc5 Rd2 49. Rb5 (261.75) I don't understand this...Is the engine too weak to see any easy win? |
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| Aug-01-08 | | johnlspouge: <<zooter> wrote: [snip] This seems an easy win, but Crafty 22 gives 17 +3.25 40. Re6 Qf7 41. Rf6 Qe7 42. Qf5 Qe1+ 43. Kh2 Qe5 44. Qxe5 Rxe5 45. Rxd6 Re2+ 46. Kh3 Kxh7 47. Rc6 Rxa2 48. Rxc5 Rd2 49. Rb5 (261.75) I don't understand this...Is the engine too weak to see any easy win?> Hi, <zooter>. Computers are notoriously poor in evaluating all but the simplest endgames. They look ahead, whereas I can see features in complicated endgames and recognize features that indicate a win. They and I therefore differ on what we consider the best way to win. In particular, I prefer to maintain a win with a simple variation, to avoid human error. I simply recognized the line I gave as both simple and winning. I cannot speak for Crafty's view on its variation, but in a few years, Crafty might be speaking for itself :) |
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| Aug-01-08 | | ruzon: My first thought was 36.Qg4+, but I had no follow-up. So I thought that g5 looked like a better square to be on and came up with 36.Rxf6 Rxf6 37.Qg5+, but I could not see 38.Re6 so it seemed like another dud. Then I saw that Black doesn't have too many moves, so I went with 36.g4 with g5 coming after I put my king and rook someplace intelligent. What's Black going to do if I take extra time? |
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| Aug-01-08 | | johnlspouge: <<ruzon> wrote: [snip] What's Black going to do if I take extra time?> I dunno. Maybe he will have a heart attack.
I don't think you are demonstrating the proper attitude, <ruzon> :) I agree there is little immediate need for tactical fireworks, but eventually White has to do something dramatic to break the Black defenses on the 7-th rank. |
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| Aug-01-08 | | Samagonka: <sexymichelle7> I feeel you. Can we meet somewhere for a game of chess?:) |
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| Aug-01-08 | | ellhares: thats easy one these time!!
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| Aug-01-08 | | DavidD: A nice puzzle that illustrates some good points about how chess players think. There are several tries here, or candidate moves, as many players point out. In fact, unless the game move Rxf6! leaped out at you immediately (or you remembered to examine all checks and captures in the position), then examining the other tries will lead you to the conclusion that they just aren't forceful enough. So now you have to look for a stronger, more forcing move. That should lead you to think of Rxf6 as possible. Players commenting on this position and listing only one candidate move (the game move Rxf6) probably looked at other moves too. In general, dzechiel's comments more closely describe how a chess player thinks or should think than any other player. A lot can be learned by reading his comments. |
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Aug-02-08
 | | Bishoprick: It seems to me that the reason for the resignation is not the outside pawn, but that Black is about to lose his Queen, wherever he goes to get out of check. The threat is Rook to e7. To avoid it Black's King has to go to either f7 or f8, which leads to Rf6+ and mate or loss of Queen follows. If the Black King goes to h8, then R to e7 and mate on the move. What am I missing that everyone else saw? |
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Aug-02-08
| | Once: <bishoprick> 40. ... Kh8 41. Re7 Rg8 (41. ... Qxe7 just loses material) 42. Qf6+ Rg7 43. Qxg7# 40. ... Kf8 41. Qf6+ Kg8 (if 41. ... Qf7 42. Qxd8) 42. Re7 and black has to give up his queen to avoid Qg8# Don't need to worry about passed pawns- outside or otherwise! |
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Aug-02-08
| | Bishoprick: Yep, I agree with Once. No matter what, at the very least the Black Queen goes bye-bye. There are a couple of other variations possible, but they lead to the same result or worse. The resignation was the right decisions based on the looming disaster. |
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| Aug-07-08 | | gandu: <al wazir: gandu: after 36. Rxf6 Re8 37. Rfe6 Ref8 38. f6+ Kh8 39. Re7 Qd8 40. Qh6 Kg8.
I see no toast here.>
What about then 41 Re4? Double toast! ;-)
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| Aug-15-08 | | patzer2: For the Friday August 1, 2008 puzzle solution, White plays the demolition sham sacrifice 36. Rxf6!!, offering the Rook as a temporary sacrifice to set up a decisive attack against the now helpless King. As <Random Visitor> observes, Black's last best chance to hold the position was 33...hxg3=! Below is an analysis, beginning with the critical 33rd move, which was checked move-by-move with Fritz 8: <33. Qf4 Rd8?>
This is a weak move because it overlooked a much stronger alternative. Instead, holding the position with equality is 33...hxg3!, when play might continue 34. Qxg3+ (34. Rxf6 Rxf6 35. Qg5+ Kf7 36. Re6 Qd8! 37. Qh5+ Kg7 38. Qg5+ Rg6 39. Rxg6+ hxg6 40. Qxg6+ Kf8 41. Qh6+ Ke8 42. f6 Rb7 43. Qh8+ Kd7 44. Qg7+ Kc8 45. f7 Rxf7 46. Qxf7 Qd7 47. Qf8+ Kc7 48. Qa8 =) 34... Kh8 =. <34. Qxh4 Rdf8>
Black may be able to organize a difficult defense after 34...Rg8 35. Qf4 Kh8 36. Kh2 Rfg7 37. Rxf6 Rxg3 38. Rxd6 Rg2+ 39. Kh1 Qg71 40. Rg6! Rxg6
41. fxg6 Rf8  with practical drawing chances.
<35. Qf4 Rd8>
Black's position is tenuous (probably lost against best play) and he understandably wants to prevent the near decisive Rxe6. However, with this move Black gives White a perfect set up for the coming Rook sacrifice. Instead, Black can put up more resistance with 35... Ra8 36. Rxd6 Qa4,
even though White wins after 37. Rc6 Qc2 38. Rc7 Qc3 39. Re2 Rxc7 40. Qxc7+ Kh8 41. Qd6 Rg8 42. Kh2 Qd4 43. Qe7 Rg7 44. d6 h6 45. Qe3 Qxe3 46. Rxe3 Rd7 47. Rd3 Kg7 48. Kg2 Kf7 49. Kf3 Ke8 50. Ke4 Ra7 51. Rd2 Ra3 52. g4 Rg3 53. Kd5 Rxg4 54. Re2+ Kd8 55. Rh2 Rg3 56. Rxh6 Ra3 57. Kc6 Ra6+ 58. Kxc5 Kd7 59. Rh7+ Ke8 60. Kd5 Rxa2 61. c5 Rd2+ 62. Kc6 Kf8 63. d7 b3 64. Kc7 b2 65. Rh1 b1=Q 66. Rxb1 Ke7 67. c6 Rd3 68. Re1+ Kf8 69. d8=Q+ Rxd8 70. Kxd8  . <36. Rxf6!!> White plays the demolition Rook sacrifice for a decisive combination to destroy the Black King's remaining pawn cover and bring his Queen and the remaining Rook in for a heavy artillery attack that will overwhelm the now helpless and unprotected King. If 36... Kxf6, then White wins after 37. Qh6+ Kxf5 38. Re6! . <36...Rxf6 37. Qg5+! Kf7 38. Re6! Rxf5 39. Qxf5+ Kg8> If 39... Kg7, then White wins after 40. Qf6+ Kg8 41. Re7 Qxe7 42. Qxe7 Ra8 43. Qxd6 . <40. Qg5+!> 1-0.
Black resigns in the face of nothing but losing possibilities, such as 40...Kh8 (40... Kf7 41. Qf6+ Kg8 42. Re7 ; 40... Kf8 41. Rf6+ Qf7 42. Rxf7+ Kxf7 43. Qxd8 ) 41. Re7 . |
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Kibitzing
sac: 36.Rxf6