< Earlier Kibitzing · PAGE 2 OF 2 ·
|Apr-28-10|| ||tarek1: I don't know why, I left out one line in which Black queens first : <60.c7 Ra8 61.g6 c3 62.g7 c2 63.Rh8 c1Q 64.Rxa8>|
click for larger view
Black has a queen but two white pawns are one square away from queening. Does black have a perpetual ?
It looks unlikely but I don't know. This is tricky so 60.g6 is certainly easier.
|Apr-28-10|| ||tarek1: I've just read <SamAtoms1980> post and in the position above Black wins !
I had seen that 60.g6 wins but then I convinced myself that c7 was quicker and more forcing, forgettting to check that tricky line.
|Apr-28-10|| ||agb2002: White is a pawn ahead.
Black threatens 60... c3 followed by ... Ra4+ and ... Rc4.
Active play suggests 60.g6:
A) 60... c3 61.g7
A.1) 61... Kf7 62.c7 Ra8 63.Rh8 c2 64.c8=Q Rxc8 65.Rxc8 Kxg7 66.Rxc2 + - [R].
A.2) 61... Ra8 62.Rh8 c2 (62... Rxh8 63.gxh8=Q c2 64.Qc3 + -) 63.Rxa8 c1=Q 64.g8=Q+ Ke5 (64... Ke7 65.Re8+ Kf6 66.Re6#) 65.Ra5+
A.2.a) 65... d5 66.Rxd5+ Kf6 (66... Ke4 67.Qe6#) 67.Rd6+ (or 67.Qg5+ Qxg5 68.Rxg5) and mate soon.
A.2.b) 65... Kf6 66.Rf5+ Ke7 67.Qf7+ Kd8 68.Qd8#.
A.2.c) 65... Kd4 66.Qd5+ Kc3 (66... Ke3 67.Qg5+) 67.Rc5+ dxc5 68.Qxc5+ Kb2 69.Qxc1+ Kxc1 70.c7 + -.
A.2.d) 65... Ke4 66.Qd5+ Ke3 67.Qg5+ and 68.Qxc1 + -.
A.3) 61... Ra4+ 62.Kf3 Ra8 63.Rh8 looks similar to A.2.
A.4) 61... c2 62.g8=Q+ and 63.Qc4 + -
B) 60... Kf6 61.g7 and Black has lost one move with respect to line A.
The alternative 60.c7 seems to fail after 60... Ra8 61.g6 c3 62.g7 c2 63.Rh1 Kf7 64.Rc1 Ra4+ 65.Kg5 Rc4 66.Kh6 Kg8 because Black promotes with check (67.Rf1 c1=Q+ 68.Rxc1 Rxc1 - +). Now, Black only needs to take the pawn on c7, place the rook on d8 and push the d-pawn to hold the game.
|Apr-28-10|| ||gofer: This takes a little bit of working out but its all possible to calculate, so I am a little surprised that we have
even got to this position!
60 g6 ...
1) The straight run fails as white promotes with check and black doesn't.
60 ... c3
61 g7 c2
62 g8=Q+ winning
2) The rook trying to stop the g pawn fails as the king is forced onto the back rank.
60 ... Ra8
61 g7 Rg8 (Kf7 Rh8 wins)
62 c7 Kd7
63 c8=Q+ Kxc8 (Rxd8 64 g8=Q+ with mate in 4 more )
64 Rh8 winning
3) The king trying to stop the g pawn fails as black has to protect against both the c pawn and g pawns promoting.
60 ... Kf6
61 c7 Ra8 (forced)
62 Rd7 Rc8 (Black must not allow Rd8 which will ensure the premotion of the c pawn)
63 Rxd6+! Kg7
64 Rc6 ... winning as the white rook protects against Pc4 from promoting and protects Pg6 and Pc7
64 ... Kh6
65 Kf5 Rf1+
66 Ke6 Kxg6
67 Ke7+ Kg7
68 Rg6+ and black can resign
Now I think computer analysis will show that there are lots of winning moves. I think g6 is just one of those...
Time to check...
|Apr-28-10|| ||tratra: White to play
Suba vs Hebden
No time to check all variations
60. g6, c7, Rh8
1) 60. g6
a. 60...Kf6 61. g7 (Ra8? 62. Rh8 ) Kf7 62. c7 Ra8 63. Rh8
b. 60...Ra8 61. g7 (61...Kf7 62. Rh8 ) Rg8 62. c7
time to check
|Apr-28-10|| ||tratra: got it!|
|Apr-28-10|| ||whiteshark: 3 pawn moves to finish the game!|
|Apr-28-10|| ||bobtheoriginal: chess thematics:
|Apr-28-10|| ||David2009: Suba vs Hebden, 1983 White 60? Harder than usual for a Wednesday. 60 Rh8 Ra7 (forced to prevent c7 etc) 61 Re8+ Kf7 62 Rb7 c3 63 Rb7+ Rxb7 64 cxb7 c2 65 b8=Q c1=Q 66 Qxd6 with a tough but winning Queen ending two pawns up. The extra Pawn restricts Black from exchanging Queens; meanwhile White is threatening an immediate Queen exchange.|
Alternative plans don’t work e.g. 60 Rh8 Ra7 61 Kh5!? c3 62 Kg6 d5! is unclear, whilst 60 Kh5?! c3 61 Kg6 c2 62 Rh1 Rc3 probably wins for Black; or 60 g6 c3 61 g7 Kf7 and Black is OK.
Time to check and read other kibitzes:
click for larger view
White played 60 g6, a move I had dismissed, see above. Time to set the position up on Crafty:
There is a nasty hole in my analysis: Black continues 60 Rh8 Ra7 61 Re8+ Kd5! a square I thought was guarded. I had a similar optical illusion a few months ago.
User: agb2002 gives the refutation of 60 g6 c3 61 g7 Kf7: after 62 c7! Ra8 63.Rh8 c2 64.c8=Q it is all over. Crafty defends against 60.g6 with c3 61.g7 and Ra4+ but 62.Kg5 Ra8 63.Kg6 gives an easy win for White.
|Apr-28-10|| ||johnlspouge: Wednesday (Medium/Easy)
Suba vs Hebden, 1983 (60.?)
White to play and win.
Material: Up a (doubled) P. White has 2 passed Ps, Pc6 and Pg5, in a race with the Black passed Pc4. Note: (1) Pc7-c8=Q+ and Pg7-g8=Q+ yield tempi, whereas Pc2-c1=Q is not a check; and (2) the Ps on the c-file each create barriers to the opposing R. Another barrier on the d-file prevents the Black Ke6 from attaining the c-file rapidly enough to stop Pc6. Thus, Ra3 is burdened with stopping Pc6. White has only Rh7 to aid Pc6, however. Usually, the pattern 59.Rh7-h8, setting up a barrier on the d-file against Ke6 would be correct, but in this case, calculation shows Ra3 can stop c8=Q. Thus, Pg5 must also create threats.
Candidates (60.): Rb7, g6
[60.Rb7 Ra8 61.c7 Rc8 goes nowhere.]
(1) 60…c3 61.g7 Kf7 [Ra8 62.Rh8 c2 61.Rxa8 c1=Q 62.g8=Q+ wins] [else, g8=Q+]
62.c7 Ra8 63.Rh8 wins
(2) 60…Kf6 61.g7 Ra8 [Kf7 loses a tempo in Variation (1)] 62.Rh8 wins
(3) 60…Ra8 61.g7 (threatening 62.Rh8, then 63.Rxa8 or 63.g8=Q+)
White wins, as above.
I missed the game defense, but Variation (1) uses the winning idea.
|Apr-28-10|| ||wordfunph: got it! 60.g6 pushing all the way to g7 and threatening c7.|
|Apr-28-10|| ||jsheedy: I was favoring 60. Rb7, but 60. g6 seems quicker.|
|Apr-28-10|| ||JG27Pyth: An enjoyable bit of practical chess here. I was thrown off at first looking for some sac'ing "puzzle solution" type move -- and thrown off considerably longer trying to force the c pawn -- no -- then trying to force the g pawn -- no -- and then *ahah* using them both -- a bit o' g, a little c -- and White gets the win. Full Solve. Monday's 4am debacle just a distant memory now. :)|
|Apr-28-10|| ||patzer2: For today's Wednesday puzzle solution, Suba's 60. g6! wins this endgame by combining the passed pawn, pin and skewer tactics.|
For example, in the final position, after 62...Kd7 63. c8=Q+ Kxc8 64. Rh8 White has a winning pawn promotion, pin and skewer in place.
|Apr-28-10|| ||jimmyjimmy: If we have a concensus that 60.c7 is just as correct as advancing the knight pawn, then I have successful answered three consecutive daily puzzles. I am proud of this as I had previously never answered even one.|
|Apr-28-10|| ||chrisowen: The vessel in his attack is Suba's marine g6 g7. You boot the pawns. It surfaces that the hunt for red oh see to bearing holding under the c7 pawn. Conning the tower black perish coping up under mounted pressure..g6 Ra8 g7 Rg8 c7 torpedoes him.|
|Apr-28-10|| ||dzechiel: <jimmyjimmy: If we have a consensus that 60.c7 is just as correct as advancing the knight pawn, then I have successfully answered three consecutive daily puzzles. I am proud of this as I had previously never answered even one.>|
Sorry to burst your bubble, but 60 c7 is not nearly as strong as 60 g6. But don't be disappointed, there's always next week!
|Apr-28-10|| ||VincentL: In this "medium easy" position, I first looked at c7, but soon discarded it in favour of g6.|
I have analyzed a few variations, and white wins in all of them.
For example 60 g6 Ra8 61. g7. Now if 61... Kf6 62. Rh8 wins. If 61... Rg8
62. c7 Kd7 63. c8=Q+ ! Now if 63....Kxc8 64. Rh8 !. The black rook cannot capture the pawn as it is pinned.
If 60....c3 61. g7 ! (not c7). Then if 61...c2 62. g8=Q+ Ke5 and now there are many ways to win. For example 63. Rh1 Rc3 64. Qg7+ capturing the black rook next move (and the pawn the following move).
If 61.....Ra8 in this line, 62. Rh1 Rg8 63. Rc1 Rxg7+ 64. Kf3 Rc7 65. Rxc3 Kd5 66. g4 Rxc6 67. Rxc6 Kxc6 68. Kf4 Kd7 69. Kf5 Ke7 70. Kg6 Kf8 71. Kh7 d5 72. g5 d4 73. g6 d3 74. g7 Ke7 75. g8=Q d2 76. Qd5 and wins. I am sure there is an easier path in this variation, but I am out of time....
|Apr-28-10|| ||Jimfromprovidence: When you study it a bit, I think 60 c7 first then 61 g6 gets full credit; it just takes longer.|
Black's rook has to be tied down to prevent promotion with check.
After 60...Ra8 61 g6 I could not find anything effective for black.
click for larger view
For example, if black tries 61...c3 then 62 Kg5, setting up an escort for the g pawn.
click for larger view
|Apr-28-10|| ||mworld: i'm a bit disappointed in myself since I was analyzing g6 and thought it was the best move...then i just kind of thought 'c7 is more direct?!' and changed my mind without really diving into c7 and finding the complications I would need to avoid.|
|Apr-28-10|| ||YouRang: It looks like there are several ways for white to win this, including 60.c7 and 60.Rh6+. But the most forcing seems to be 60.g6. Black will lose the pawn race because white promotes at g8 with check.|
So, black must go on defense. I see two ways he might do this:
[A] 60...Ra8 <guarding the back rank with the rook>
61.g7 <threat Rh8> Rg8 <so Rh8 can be answered with ...Rxg7+>
62.c7 <threat: c8=Q+ Rxc8 and then Rh8> Kd7 <to capture c-pawn>
63.c8=Q! Kxc8 64.Rh8! <with Rxg7+ now impossible due to the pin>
[B] 60...Ra6 <preparing to move behind the c-pawn>
61.g7 <threat: g8=Q+> Kf7 <ready to capture promoted piece>
62.Rh8! <threat: g8=Q+ with Q guarded by R> Kxg7 <there goes one pawn, but the rest is automatic...>
63.c7! Rc6 <63...Kxh8? 64.c8=Q+ & QxR> 64.c8=Q Rxc8 65.Rxc8 <white's K+R v K wins easily>, e.g. 65...d5 66.Rc6 Kf7 67.Kf5 <and the pawns die>
|Apr-28-10|| ||trguitar: 60. c7 definitely has some icebergs lurking. For example, 60...Ra8 61. g6...c3 62. g7?...c2!|
I think if you want to claim 60. c7 as a solution, then you need to have seen at least this line.
|Apr-28-10|| ||wals: Rybka 3 1-cpu:3071mb hash: depth 20:
Black's game steadily deteriated,
45...Kf8 +1.07, better Rec7 +0.79.
47...Rce8 +1.67,better Rec7 +1.05.
49...Rd3 +2.96, better R3e6 +1.90
57...Rg8 +4.47, no better
58...Rxg5 +11.00,better Ra8 +4.47.
|Apr-29-10|| ||TheBish: Suba vs Hebden, 1983|
White to play (60.?) "Medium/Easy"
With two passed pawns, White wins pretty easily with 60. g6! and now:
A) 60...c3 61. g7 Kf7 (or 61...Ra8 62. Rh8) 62. c7 Ra8 63. Rh8 c2 64. Rxa8 c1=Q 65. g8=Q+.
B) 60...Ra8 61. g7 Rg8 (or 61...Kf7 62. Rh8) 62. c7 Kf7 63. Kf4 c3 64. Rh8 c2 65. c8=Q Rxc8 66. Rxc8 Kxg7 67. Rxc2.
|Apr-29-10|| ||kevin86: Looks straightforward,but I missed it.|
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