< Earlier Kibitzing · PAGE 2 OF 2 ·
|Oct-11-08|| ||chrisowen: Do the math and Psakhis plays 16.Nh3 as the start of a beautiful knight tour where it eventually reaches the g6 outpost. As soon as black swaps it off all the elements favour white's mating net.|
|Oct-11-08|| ||znprdx: Well 40.Qd1 is very pretty - and clearly qualifies as the 'puzzle' solution, but Black is so lost almost anything wins - Re4 looks crushing as does Qf4 and as others have pointed out Bh4.|
|Oct-11-08|| ||ThePawnOTron2: 40.Qd1! It is threatening Qh5 checkmate, and there is really nothing Black can do about it without losing material.|
Going in the favorite games collection.
|Oct-11-08|| ||johnlspouge: Saturday (Very Difficult)
Psakhis vs Smirin, 1995 (40.?)
White to play and win.
Material: B for N+P. The Black Kg6 has 2 legal moves to light squares and is exposed, in front of his forces instead of behind. The White battery Qc1 and Bg5 take away dark squares around Kg6, while Rh1 takes away squares along the h-file. The White Re1 defends Pe5 against Nd7, but both it and Qc1 require further activation. The White Kg2 is in the open, but is safe at g3 if required. The strongest Black defensive resource is the f-file and the outpost f5, so White should prevent …Rf8.
Candidates (40.): Rh6+, Qd1, Kg3, Re4
40.Kg3 (threatening 41.Qd1 42.Qh5# [if 41…Kxg5 42.Qg4#])
Black is remarkably helpless. Moves with Ra7 are irrelevant; the Nd7 can sacrifice itself at e5 only as a futile gesture of defiance; neither Qe8 nor Rg8 can mollify the threat by moving to the f-file; and Qe8 has only 1 relevant move. The Black defenses (such as they are) are limited to the following:
(1) 40…Rh8 41.Qd1
(threatening 42.Rxh8 Qxh8 43.Rh1, threatening 44.Qh5+ next)
After 43.Rh1, if 43…Qe8, 44.Qh5+ skewers Kg6 and Qe8; if 43…Q moves elsewhere, 44.Qh5+ Kf5 45.Bf6+ g5 46.Rf1#.
41…Rxh1 42.Rxh1 (renewing the threat on move 40.)
42…Kf7 43.Qh5+ Kf8 [g6 44.Qh7+ Kf8 45.Bh6#]
44.Qh8+ Kf7 45.Rf1+ Nf6 46.Rxf6+ gxf6
47.Qh7+ Kf8 48.Bh6+ Rg7 49.Qxg7#
(2) 40…Qb8 41.Qd1 Nxe5 42.Bf4
(3) 40…Nf6 41.exf6 gxf6 42.Rh6+
followed by taking off Pf6 with check. The position is not calm, but White is clearly winning.
(4) 40…Kf7 41.Qf4+
(threatening 41…Kg6 42.Qg4 then 43.Qh5# or 42…Nf6 Bxf6+)
41…Nf6 42.exf6 and if 42…gxf6 43.Qxf6#
|Oct-11-08|| ||kevin86: I missed this one by a country mile. I tried containment of the enemy king:40 ef1 or f4. I also tried the sac by 40 h6. neither is the answer. :(|
|Oct-11-08|| ||RandomVisitor: 1: Lev Psakhis - Ilya Smirin, Haifa 1995
click for larger view
Analysis by Rybka 3 : <18-ply>
1. (5.16): 40.Qd1
2. (4.94): 40.Kg3 Nf6 41.exf6 Qb8+ 42.Qf4 Qxf4+ 43.Kxf4 Ra2 44.fxg7 Kxg7 45.Be7 Rf2+ 46.Ke5 Kf7 47.Bxc5 Rg5+ 48.Kxd4 Rf4+ 49.Ke3 e5 50.Rh6 Rg3+ 51.Kd2 Rf6 52.Rxf6+ Kxf6 53.Rf1+ Ke6 54.Rg1
3. (3.79): 40.Re4 Rh8 41.Rg4 Kf7 42.Qf4+ Kg8 43.Rxh8+ Kxh8 44.Bh6 Qg8 45.Bxg7+ Qxg7 46.Rxg7 Kxg7 47.Qg4+ Kf7 48.Qf3+ Ke7 49.Qxc6 Ra2+ 50.Kg3 Re2 51.Qd6+ Kd8 52.b4 Re3+ 53.Kf2 Rxe5 54.bxc5 Rf5+ 55.Kg3
|Oct-11-08|| ||johnlspouge: Because Psakhis and I had a little disagreement on the best move, I ran the position through Toga II 1.3.1. (Humans can improve near the end of the complete computer variation.)|
[ply 20/78 time 1:26:03 value +5.18]
39...<Kxg6> 40.Kg3 Ra2 41.Qd1 Rh8 42.Rxh8 Qxh8 43.Rh1 Qxh1 44.Qxh1 Kxg5 45.Qe4 Kh6 46.Qg4 Nf8 47.Qf4+ Kh7 48.Qxf8 Rd2 49.Qxc5 Rxd3+ 50.Kg4 Rxb3 51.Qxc6 d3 52.Qxe6 d2 53.Qd5 Rc3 54.Qxd2 Rxc4+ 55.Kf5 g6+ 56.Kg5
Note that I left the computer running longer than I usually do ;>)
Toga disagrees with <RandomVisitor>'s Rybka 3 analysis, which says 40.Qd1 (+5.16) is better than 40.Kg3 (+4.94). The similar evaluations could be within "experimental error". Toga is churning away on 40.Qd1, but it still appears to have strong preferences for 40.Kg3.
I spent ungodly amounts of time on today's puzzle, about 2.5 hours, more than I have spent on a Saturday for months. I enumerated my first candidate 40.Rh6+ to maintain good habits (checks, captures, and threats!), then burned most of the time on my first "serious" candidate 40.Qd1. The move turns out well if Black does not say, "Show me!": 40...Kxg5. I rejected 40.Qd1 Kxg5, because I followed with 41.<Kg3>, which appears to draw:
[ply 15/65 time 01:52 value 0.00]
40.Qd1 Kxg5 41.<Kg3> Nf6 42.exf6 Kxf6 43.Qf3+ Ke7 44.Rxe6+ Kxe6 45.Re1+ Kd7 46.Qf5+ Kd6 47.Qf4+ Kd7 48.Qf5+
I could not beat 41...Nf6, apparently with good cause.
Further Toga analysis suggests that 40.Qd1 Kxg5 requires the follow-up 41.Qf3:
[ply 15/63 time 01:18 value +6.84]
40.Qd1 <Kxg5> 41.Qf3 Ra2+ 42.Kg1 Nxe5 43.Rh5+ Kg6 44.Rhxe5 Rf8 45.Rxe6+ Qxe6 46.Rxe6+ Rf6 47.Rxc6 Rxc6 48.Qxc6+ Kf7 49.Qxc5 Ra1+ 50.Kg2 Rb1 51.Qd5+ Kf8 52.Qa8+ Ke7 53.Qa2 Re1 54.Qa7+ Ke6 55.Qxd4
Because the last 2 evaluations are my usual Mom-and-Pop 15 plies, they probably need to be checked.
I prefer 40.Kg3 to 40.Qd1, because it retains the same threats without investing Bg5 prematurely, the problem in the faulty variation that permits a draw. Psakhis obviously has nerves of steel.
|Oct-11-08|| ||johnlspouge: < <znprdx> wrote : Well 40.Qd1 is very pretty - and clearly qualifies as the 'puzzle' solution, but Black is so lost almost anything wins - Re4 looks crushing as does Qf4 and as others have pointed out Bh4.>|
Here are Mom-and-Pop Toga II 1.3.1 evaluations of "almost anything". The last move entered into the computer is <emphasized>. Humans can improve near the end of the full computer variation.
[ply 15/54 time 01:28 value (to White) +2.09]
40.<Re4> Rh8 41.Rg4 Kf7 42.Qf4+ Kg8 43.Rxh8+ Kxh8 44.Bh6 Ra2+ 45.Kg3 Qe7 46.Bxg7+ Qxg7 47.Rxg7 Kxg7 48.Qg4+ Kf7 49.Qf3+ Ke7 50.Qxc6 Re2 51.Qd6+ Kd8 52.Qxe6 Rxe5 53.Qg8+ Kc7
[ply 15/47 time 00:36 value (to White) +0.35]
40.<Qf4> Ra2+ 41.Kg1 Rh8 42.Qg4 Rxh1+ 43.Kxh1 Kh7 44.Rg1 Ra7 45.Bf6 Nxf6 46.exf6 g6 47.Kg2 Kg8 48.Qg5 Qf7 49.Kf3 Kh7 50.Rh1+ Kg8 51.Kg4
[ply 15/46 time 00:36 value (to White) -1.15]
40.<Bh4> Ra2+ 41.Kg1 Rf8 42.Rh3 Rf5 43.Qb1 Qa8 44.Bg3 Kf7 45.Rh8 Qxh8 46.Qxa2 Qh3 47.Qg2 Qg4 48.Rf1
My chessforum has instructions on how to download Toga, which is freeware.
|Oct-11-08|| ||MiCrooks: Interesting that Kg3 works if done right away simply because you are not piece down at the time! So the Knight sack gives you a free piece. However, I would prefer the ending positons of the Qd1 line, with the Black Queen off the board. The Queen versus Rook ending holds no danger for White. |
You DID have to see the Qf3 line on KxB but if you are going to hang a piece you have to have considered the consequences of your opp taking it :)!
|Oct-11-08|| ||johnlspouge: < <MiCrooks> wrote: [snip] You DID have to see the Qf3 line on KxB but if you are going to hang a piece you have to have considered the consequences of your opp taking it :)! >|
Ironically, if I saw 40.Qd1 during a game (fat chance!), I would have played it. I burned so much puzzle time because 40.Qd1 felt "right". Unfortunately, it would shame me to write "it felt right" as a puzzle solution :)
|Oct-11-08|| ||johnlspouge: Toga II 1.3.1 does indeed seem to prefer 40.Kg3 to 40.Qd1, but not by enough to make any strong point about the best move:|
[ply 20/80 time 1:36:45 value +4.96]
40.<Qd1> Rh8 41.Kg3 Nxe5 42.Rxh8 Qxh8 43.Rxe5 Qe8 44.Rxc5 Ra6 45.Be3 Kh7 46.Bxd4 Qg6+ 47.Qg4 Qxg4+ 48.Kxg4 Ra3 49.Rxc6 Rxb3 50.Rxe6 Rxd3 51.Rd6 Rd2 52.Rd7 Rc2 53.c5 Kh6 54.Bxg7+ Kg6 55.Bd4 Rg2+ 56.Kf4
|Oct-11-08|| ||5hrsolver: I actually considered 40.Bh4 before I saw 40.Qd1. Considering that it is a puzzle I felt the need to sacrifice something. That's when I saw 40.Qd1. |
I had 42.Qg4 instead of the actual game 42.Rxh8. I guess it is best to keep things simple.
|Oct-11-08|| ||lost in space: A real complicated one....
40. Qd1 Rh8
or 40...Ra2+ 41. Kg3 Rf8 42. Qh5+ Kf5 43. Rhf1+ and mate to follow
41. Qg4 Ra2+ 42. Kg3 Kf7
or 42...Qa8 43. Bf6+ Kf7 44. Qxg7+ Ke8 45. Qe7#
43. Rxh8 Qxh8 44. Rf1 Nf6
or 44...Kg8 45. Qxe6+ Kh7 46. Rh1+ and mate to follow;
or 44...Kg6 45. Be7 Kh7 46. Rh1+ Rh2 47. Rxh2+ Kg8 48. Qxe6#
45. Qh3 Rb2 46. exf6
After this I am asking myself if my second candiadate move 40. Kg3 is also winning.
Time to check
|Oct-11-08|| ||lost in space: Oups, forgot one line:
40. Qd1 Kxg5 41. Qf3 Ra2+ 42. Kg1 Nxe5 43. Rh5+ Kg6 44. Rhxe5 Rf8 46. Rxe6
By the way: miles more complicated than other Friday's
|Oct-11-08|| ||MostlyAverageJoe: <JimmyRockHound: OK - so why can't black just take the bishop?>|
Others have already posted some analysis of 40. Qd1 Kxg5 41. Qf3, so I'll just post the closure of that line:
After about 30 seconds, Hiarcs 12.1 claims that it would lead to a forced mate in 21 moves. Below, double exclamations mark the uniquely winning moves (where anything else would draw or lose). Single exclamations mark the unique continuations forcing the mate (anything else delays the mate beyond the engine's horizon).
40. Qd1 Kxg5 41. Qf3!! Ra2+ 42. Kg1!! Nxe5 43. Rh5+! Kg6 44. Rhxe5! Rf8 45. Rxe6+! Qxe6 46. Rxe6+!! Rf6 47. Qe4+! Kh6 48. Re5 g6 49. Qh4+! Kg7 50. Re8! Rf8 51. Qe7+! Rf7 52. Qe5+! Kh6 53. Rh8+ Rh7 54. Qf4+ g5 55. Qf6+ Kh5 56. Rg8 Rg7 57. Rxg7 Ra1+ 58. Kg2 Ra2+
59. Kg3 Rg2+ 60. Kxg2 g4 61. Rh7#
I somehow :-) missed that forced line and settled for 40.Re4.
|Oct-11-08|| ||MostlyAverageJoe: <johnlspouge: Toga II 1.3.1 does indeed seem to prefer 40.Kg3 to 40.Qd1>|
Hiarcs agrees with Toga, but the difference between the evaluations is trifling. 21 plies:
1. (+5.53) 40. Kg3 Ra2 41. Qd1 Rh8 42. Rxh8 Qxh8 43. Rh1 Qxh1 44. Qxh1 Kxg5 45. Qh4 Kg6 46. Qe7 Re2 47. Qe8 Kg5 48. Qxd7
2. (+5.21) 40. Qd1 Rh8 41. Kg3 Nxe5 42. Rxh8 Qxh8 43. Rxe5 Qe8 44. Qg4 Kf7 45. Qh5 Kf8 46. Qxe8 Kxe8 47. Rxe6 Kf7 48. Rxc6 Ra1 49. Kf3 Rf1 50. Ke2 Rf5 51. Rc7 Ke8 52. Rxg7 Kf8 53. Bh6 Rh5 54. Rg6 Kf7 55. Ra6 Rh2 56. Kf3
3. (+2.34) 40. Re4 Rh8 41. Rg4 Kf7 42. Qf4 Kg8 43. Rxh8 Kxh8 44. Bh6 Ra2 45. Kg3 Qe7 46. Bxg7 Qxg7 47. Rxg7 Kxg7 48. Qg4 Kf7 49. Qf3 Ke7 50. Qxc6 Rd2 51. Qe4 Kd8 52. Qf3 Kc7 53. Kf4 Rb2 54. Qd1 Rf2 55. Ke4
|Oct-11-08|| ||Woody Wood Pusher: wow fun...can't wait for Sunday LOL|
|Oct-11-08|| ||whiteshark: I knew this one.|
|Oct-11-08|| ||johnlspouge: Thanks, <MostlyAverageJoe>. I had you in mind :)|
<Because the last 2 evaluations are my usual Mom-and-Pop 15 plies, they probably need to be checked.>
|Oct-11-08|| ||DarthStapler: I considered the first move at least|
|Oct-11-08|| ||Zorts: I considered 40.Bh6, g7xh6 41.Qh6+ not being afraid of the discovery check by the g8 rook, but overlooked the impending a2 check by the other black rook.|
|Oct-11-08|| ||Zorts: Perhaps 40.Bh6, g7xh6 41.Qh6+, Kf7 42.Kh3 is winning for white?|
|Oct-13-08|| ||agb2002: The black king looks in danger.
A) 40.Bh6 gxh6 41.Qxh6+
A.1) 41... Kf5+ 42.Kf3 Nxe5+ 43.Rxe5+ Kxe5 44.Qf4 mate.
A.2) 41... Kf7+ 42.Kf3 Nf8 is unclear.
B.1) 40... Qa8 41.Qg5+ Kf7 42.Rhf1+ Nf6 43.exf6 gxf6 44.Rxf6+ Ke7 45.Rg6+ winning.
B.2) 40... Rf8 41.Qg5+ Kf7 42.Ref1+ Kg8 is unclear.
C.1) 40... Rf8 41.Qg4 Kf7 42.Qh5+ Kg8 43.Qh7+ Kf7 44.Rhf1+ winning.
C.2) 40... Qf7 41.Qg4 Ra2+ 42.Bd2 mate.
C.3) 40... Rh8 41.Qg4 Rxh1 42.Bh6+ Kxh6 43.Rxh1+ and mate next move.
Line C) seems to be the best option. Let’s see.
|Oct-13-08|| ||agb2002: A rather poor work, specially taking into account that I actually saw Qd1 and Kg3 but discarded them because I was unable to tie up all the loose ends. I'll try to find out why later.|
|Oct-24-08|| ||patzer2: For the Saturday Oct 11, 2008 puzzle solution, White prepares a decisive attack to finish off a pursuit combination against Black's helpless King with 40. Qd1! |
Also winning is 40. Kg3! See analysis above posted by <RV>, <johnlspouge> and <MAJ>.
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