|
< Earlier Kibitzing · PAGE 2 OF 2 ·
Later Kibitzing> |
Jul-19-09
 | | sackman: Nice finish! I saw the winning line as far as Qc3 with the threat of Rh7# and couldn't see a defence in my head, a pleasant surprise for me to see that there wasn't one. |
|
| Jul-19-09 | | David2009: Sunday's problem Varavin vs V M Kozlov, 2002 20? Insane. White is a Pawn down with a strong attack and a big lead in development. So I expect a combination. However, the 'insane' rating means that the win will be hard to find (in a real game I wouldn't have this clue). So there should be no obvious win and indeed the obvious
forcing sequence 20 Rxg8 Kxg8 21 Rg5+ hxg5 22 Qxg5+ leads to nothing. Black's N at f6 is a tower of strength. 20 Rbg5 is promising; e.g. (A) ...hxg5 21 Qxg5 with a promising attack or (B) ...Qxd4 21 Rxg7 Qa8+ 22 Bf1
threatening 23 Qxh6 mate and I cannot see a defense or (C) 20... Rg8 21 Rxg7 Rxg7 22 Qxh6+ Rh7 23 Qxf6+ Qxf6
24 Rxh7 mate. So far so good. Another look at variation (A): 21..Ne8 allows 22 Qxd8; 21 Rg8 allows 22 Qh4+ etc.
So Rbg5 is the move and seems to win in all variations. Let's try it. ===========
More or less. Black chose my defense (B) and I missed 21 ...Qh4 (i.e. I assumed Black would stay on the long diagonal). 22 Qc3 is the obvious follow-up threatening 23 Rh7 mate. Time to read other people's comments. |
|
| Jul-19-09 | | butilikefur: Hey <Athamas>, after 20. Rbg5 Ng4 21. R5xg4 Qf6 White can just play 22. Rxg7 and Black must play Qxg7 to stop Rh7+ mate - 23. Rxg7 Kxg7 24. Qf4 is clearly won but from the initial position there is no forced mate. |
|
| Jul-19-09 | | vaskokibika: <al wazir: Now what?>
23. Rh3+ Kg8
24. Bh7+ Kh8
25. Bg6+ Kg8
26. Rh8+
and mate in 2 |
|
Jul-19-09
 | | sbevan: Rxg7 Kxg7 (else Qxh6 mate)
if ..Ng4 to defend the h6 P Rxg4 and its still mate.Rg5+
1. ...Kh8
Rh5
If ...Nxh5
Qxh6
2....h6x(g5)
Qxg5
Let's see |
|
Jul-19-09
| | sbevan: Sorry, I should have been more precise with R(b)
And I missed the QxN but that's spite isn't it ans the sequence is forced anyway... |
|
| Jul-19-09 | | Summerfruit: Black is a pawn up.
White's pieces are directed towards black's king side and black's queen side is poorly developed. The following seems to be a killer: 20.Rbg5!
a) 20...hxg5 21.Qxg5
a1: 21...Nh5/Ne8 22.Qh5+ Kg8 23.Qh7#
a2: 21...Rg8 22.Qh4+ Nh7 23.Qxh7#
a3: 21...g6 22.Qh6+ Kg8/Nh7 23.Bxg6/Rh3 and mates.
So the rook Rg5 is immune to capture, which leaves:
b) 20...Ne8 21.Rxg7 Qh4/Qf6 (Nxg7 22.Qxh6+ and mates, Qg5 22.Rh7+ Kg8 23.Rxg5+ hxg5 24.Qxg5+ and mates) 22.Rh7# c) 20...Nh5 21.Rxg7 etc. (similar to b)).
d) 20...Rg8 21.Rxg7 Rxg7 22.Qxh6+ Rh7 23.Bxh7 and wins. e) 20...g6 21.Rxg6 fxg6 22.Qxh6+ Nh7 (Kg8 23.Qxg6+ and mates) 23.Bxg6 Qe7 24.Bxh7 and wins, e.g.: e1: 24...Qxh7 25.Qxf8 Qg8 26.Qxg8#
e2: 24...Rf7/Rf6 25.Rg8#
e3: 24....Qf6 25.Bg6+ Kg8 26.Qh7#
f) 20...Qxd4 21.Rxg7 Qh4 (Ng8 22.Rh7#) 22.Qc3 and wins. g) 20...Ng8 21.Rxg7 f5 (to stop 22.Rh7#) 22.Rxg8+ Rxg8 23.Qxh6# |
|
| Jul-19-09 | | TrollKing: YES!!
This is only the second Sunday puzzle I have ever solved. I am now something like 2/1000.
If that ... :-) |
|
| Jul-19-09 | | randomsac: Awesome combo. Relatively simple for Sunday (I still missed it). That's just a moment when any experienced spectators would go "Ohhh!" |
|
| Jul-19-09 | | johnlspouge: < <butilikefur> wrote: [snip] if you don't see Qc3 then it appears as if Qh4 holds. > < <DoubleCheck> wrote: <<<remolino>: 22. Qc3 does it but it is very difficult to see many moves in advance, it is such a quiet move>> > Usually, when a candidate is right, you get a warm, fuzzy feeling as the soft center of the defense gives way in every variation. The defense 21...Qh4 looked awfully good, but 20.Rbg5 already felt better to me, so I looked hard for a refutation of 21...Qh4. Except for the candidate 20.Rbg5, which was subtle and non-forcing, 22.Qc3 was the hardest move to find today. Although forcing candidates are essential for an initial pruning of the decision tree, consideration of secondary, non-forcing candidates is important, too. Usually, elements in my positional analysis point to the candidate, as the weakness of the dark-square P-chain did today. I found 22.Qc3, because discovered attacks are extremely potent, and I now consciously consider them by simply ignoring intervening pieces in the "x-ray". Similarly, although mate threats are not immediately forcing, they are often as compelling as checks. |
|
| Jul-19-09 | | johnlspouge: Sunday (Insane):
Varavin vs V M Kozlov, 2002 (20.?) White to play and win.
Material: Down a P. The Black Kh8 has 1 legal move, g8. The White Bd3 steals the luft square h7 and controls critical light squares in the Black K-position. The White Rg3 x-rays g8 through Pg7 on the semi-open g-file. The White Qd2 attacks Ph6, making the dark-square P-chain protecting the Black K-position look shaky. White can immediately move the lifted Rb5 to the K-position. The White Nd4 is centralized and can aid an assault on Kh8. The Black Q-side is almost undeveloped, so White has the local superiority to support a sacrificial attack. The Black Qd8 threatens the loose Nd4. The White Kg1 is vulnerable to back-rank mates, but secured from checks. Candidates (20.): Rxg7, Qxh6+, Rbg5
20.Rbg5 (threatening 21.Rxg7)
(1) Black can accept the passive sacrifice of Ne4:
20…Qxe4 21.Rxg7 (threatening 22.Qxh6# or 22.Rh7#)
21…Qh4 22.Qc3 (threatening 23.Qxf6 24.Rh7# or 23.Rh7+#) The conjunction of Qc3, Nf6, Rg7, and Kh8 on the a1-h8 diagonal threatens double check and mate with 23.Rh7+#, if Nf6 moves. Even 22…Qxg3 23.Rxg3 leads to mate, so Black has no defense. (2) Black can accept the passive sacrifice of Rg5:
20…hxg5 21.Qxg5 (threatening 22.Qxg7#)
22…<g6> [Ne8 23.Qh5+ Kg8 or Nh7 24.Qh7#] <[Toga gives 22...Ng4 23.Rh3+ etc. as a better defense, but White still mates.]> 23.Qh6+ Kg8 [Nh7 24.Rh3 (threatening 25.Qh7#) mates]
24.Bxg6 (threatening 25.Bh5# or 25.Bh7+ Kf7 26.Rg7+ Ke8 27.Qg6+ Rf7 28.Qxf7#) 24…Qe7 [or Qd7] [or Qc7] [Rf7 25.Bh7+#] [fxg6 25.Qxg6+ Kh8 26.Qg7#] 25.<Bh5+> Ng5 26.Rxg5+ Qg7 27.Qxg7# <[Toga points out the obvious improvement: 25.Bh7+ Kh8 26.Qg7#.]> (3) 20…g6 21.Rxg6 fxg6 [else, 22.Rxh6+ 23.Rxh7#]
22.Qxh6+ Nh7 [Kg8 23.Bxg6 transposes to Variation (2)] 23.Bxg6 (threatening 24.Qxh7#)
(3.1) 24…Qe7 [or Qd7] [or Qc7] 25.Bxh7 (threatening 26.Bg8+ Qh7 27.Qxh7#) 25…Rf7 [Qxh7 26.Qxf8+ Qg8 27.Qxg8#]
26.<Bg8+> 26…Rh7 27.Bxh7 (renewing the threat) <[Toga gives the faster 26.Rg8#.]> Black has no defense because throughout, the immobile White Ne4 runs interference on the back-rank mate …Qd8-d1#. (3.2) 23…Rf7 24.Bxf7 (threatening 25.Qg7# or 25.Rg8#) 24…Qf8 25.<Qxf8+> Nxf8 26.Rg8+ Kh7 27.Rxf8 The final scorpion sting permits White to emerge N+2P ahead. <[Toga gives mate-in-13 after 25.Qh5.]> |
|
| Jul-19-09 | | bengalcat47: I see that, even in this day and age, some people have yet to learn that pawn-grabbing expeditions will only lead tt trouble. |
|
| Jul-19-09 | | 5hrsolver: I got this one all the way to 22.Qc3. Like dzechiel I tried out 20.Rxg7 first but did not find anything convincing. 20.Rbg5 brings all of whites forces to bear on the enemy king. Great puzzle. I actually still have not solved saturdays puzzle yet. |
|
Jul-19-09
 | | agb2002: White is a pawn down but can force the destruction of the black castle with 20.Rbg5: A) 20... hxg5 21.Qxg5 g6 (21... Rg8 22.Qh4+; 21... Ne8 22.Qh5+) 22.Qh6+ Kg8 (22... Nh7 23.Rh3 + -) 23.Bxg6 (threatens 24.Bh7+ Kh8 25.Qg7#, 24.Bd3+ and mate in two, 24.Bxf7+ Kxf7 25.Rg7+ Ke8 26.Qg6+ Rf7 27.Qxf7#) A.1) 23... fxg6 24.Qxg6+ Kh8 25.Qg7#.
A.2) 23... Qxd4 24.Be4+ and mate in two.
B) 20... Qxd4 21.Rxg7 (threatens 22.Qxh6+)
B.1) 21... Qa1+ 22.Bf1
B.1.a) 22... Ng8 23.Rxg8+ Kh7 (23... Rxg8 24.Qxh6#) 24.Rxf8 + -. B.1.b) 22... Ng4 (threatens 23... Qxg7) 23.R7xg4 Qf6 24.Rh3 Kh7 25.Rgh4 + -. B.2) 21... Qh4 22.Qc3 (threatens 23.Rh7# and 23.Qxf6 Qxf6 24.Rh7#) B.2.a) 22... Rd8 23.Qxf6 Rxd3 24.Rg8+ Kh7 25.R3g7#.
B.2.b) 22... e5 23.Qxe5 + -.
B.2.c) 22... Qxg3 23.Rxg3 + -, the knight is lost.
C) 20... e5 21.Rxg7 Ng4 22.Qxh6+ Nxh6 23.Rh7#.
D) 20... g6 21.Rxg6 fxg6 (21... Ng8 22.Rxh6+ Nxh6 23.Qxh6#; 21... Ng4 22.Qxh6+ Nxh6 23.Rh6#) 22.Qxh6 Nh7 (22... Kg8 23.Qxg6+ Kh8 24.Qg7#) 23.Bxg6 Qe7 (23... Rf7 24.Bxf7 + -) 24.Bxh7 Qf6 (24... Qxh7 25.Qxf8+ Qg8 26.Qxg8#) 25.Bg6+ Kg8 26.Qh7#. Another option is 21.Rh5 Nxh5 (for example) 22.Qxh6+ Kg8 23.Bxg6 fxg6 24.Qxg6+, etc. E) 20... Rg8 21.Rxg7 Rxg7 22.Qxh6+ Rh7 23.Bxh7 + - (threatens 24.Bd3+ and 24.Qg7#). F) 20... Ne8 21.Rxg7 Nxg7 (21... Qf6 22.Rh7#) 22.Qxh6+ Kg8 23.Qxg7#. |
|
| Jul-19-09 | | Samagonka: I considered at least 3 options and Rbg5 was actually one of them. I never bothered to go any further thinking that it being a Sunday, the combination would be quite copmlex. It however turned out to be fair, provided one could foresee the deadly knight pin on f6. It takes some ingenuity to smell that. |
|
| Jul-19-09 | | Utopian2020: I got 20. Rbg5, but I calculated black's 20...Ng4, then 21. R5xg4 g5 22 Rh4 Kg8 23 Rxh6 f6.... Which holds off mate for several more moves, but black has lost. |
|
| Jul-19-09 | | TheChessGuy: Nice to see the French get reamed like this. The combination is not too difficult, and reinforces the huge advantage that having active rooks brings. |
|
| Jul-19-09 | | gofer: This was a little unlike a normal "insane", white seemed to have no real attack and so 99% of the possible moves could be ruled out very quickly. So I think that yesterday's puzzle was more difficult... 20 Rbg5
20 ... Qxd4 21 Rxg7 Qh4 22 Qc3 winning
20 ... Rg8 21 Rxg7 Rxg7 22 Qxh6+ Rh7 23 Bxh7 mating
20 ... hxg5
21 Qxg5 ... (threatening Qxg7#)
21 ... Rg8 22 Rh3+ mating
21 ... Nh5 22 Qxh5+ mating
21 ... Ne8 22 Qh5+ mating
21 ... g6 22 Qh6+ Kg8 (Nh7 23 Rh3 mating) 23 Rh3 Nh5 24 Rxh5 gxh5 25 Qh7# The following is probably the main line...
20 ... g6 21 Rxg6 fxg6 (Ng8/Ng4 22 Qxh6+ Nxh6 23 Rxh6#) 22 Qxh6+ Nh7 23 Bxg6 Rf7 (Qe7 24 Bxh7 Qf6 25 Bg6+ Kg8 Qh7#) 24 Bxf7 Qf8 25 Rg8+ Qxg8 26 Bxg8 Kxg8 27 Qg6+ Kh8 28 Qe8+ Kg7 29 Nxe6 (trying to force white to simplify if black doesn't simply then White has just won another pawn and brought another piece in to attack the king) Bxe6 30 Qxa8 and winning the a7 pawn to give white a 5 pawn advantage! (regardless of the Q v B+N) - game over... It time to check... |
|
Jul-19-09
 | | al wazir: <butilikefur, vaskokibika: 20. Rg5 hxg5 21. Qxg5 Ng4 22. Rh3+ Kg8 23. Bh7+ Kh8 24. Qxg4 Qf6 (24...g6 25. Bxg6+ Kg7 26. Bh7+ Kh8 27. Bg8+ <Qh4 28. Rxh4>#) 25. Bg6+ Kg8 26. Rh8+ Kxh8 27. Qh5+ Kg8 28. Qh7#.> Thanks. If that's what it takes for white to win after black accepts the sac, then this puzzle is beyond insane. I will never believe that Varavin calculated the whole sequence of moves in advance. |
|
| Jul-19-09 | | johnlspouge: < <al wazir> wrote: [snip] If that's what it takes for white to win after black accepts the sac, then this puzzle is beyond insane. I will never believe that Varavin calculated the whole sequence of moves in advance. > My gosh, <al>, why on Earth would Varavin bother calculating best play, complete with every detail in every pullulation? After 20…hxg5 21.Qxg5 Ng4, White can just play 22.Qxg4 with the equivalent of being a clear P up. (Material is equal, Black's K is precarious, only his Rf8 is developed, and it faces all the White pieces alone.) We all have different aims in solving a CG puzzle: whereas some might drill everything down to a mate, my aim is to justify a candidate by demonstrating the equivalent of a clear P up in every variation. Under that criterion (Kotov's), 21...Ng4 is hardly worth listing. I know this is just a post-hoc justification for my not examining 21...Ng4 seriously. My protestant upbringing notwithstanding, however, I am lazy and very proud of it. My laziness is of the practical variety. |
|
Jul-19-09
| | al wazir: <johnlspouge: . . . After 20…hxg5 21.Qxg5 Ng4, White can just play 22.Qxg4 with the equivalent of being a clear P up. (Material is equal, Black's K is precarious, only his Rf8 is developed, and it faces all the White pieces alone.)> I'm not sure what you mean by "material is equal." As I look at the board, white is down an exchange after 22. Qxg4. But maybe you mean that white's lead in development and the perilous situation of black's ♔ compensate for that? Your several posts get right to the heart of what I was saying about calculating a line in detail. I suspect that (grand-)masters routinely embark on combinations such as this without trying to do exhaustive analysis. Instead, they rely on their positional and combinational intuition. But only the player who made the moves knows, and even if he addresses this point he may not tell the truth. It follows that these bold sacrificial combinations sometimes fail. Sometimes the defender has a single hard-to-find resource that saves the game, and the sacrifice then gets annotated as a blunder. But <CG> (usually) doesn't post such positions as problems. (Imagine how the kibitzers would bitch and moan if they did!) In fact, <CG> checks with an engine to make sure that the puzzle is "sound." When I try to solve one of <CG>'s more difficult puzzles,I give myself full credit only if I find the right key move and the entire winning continuation after each of black's replies. (If the winning moves are obvious or if I think I would have found them OTB, I cut myself some slack.) But if my suspicions are right, struggling to visualize the whole solution in advance and "get it right" will NOT train me to think like a GM, because GMs don't think that way. My aim is to learn to find the winning move whenever one exists, and to avoid making moves that only look as if they win. |
|
| Jul-20-09 | | johnlspouge: < <al wazir> wrote: <johnlspouge: . . . After 20…hxg5 21.Qxg5 Ng4, White can just play 22.Qxg4 with the equivalent of being a clear P up. (Material is equal, Black's K is precarious, only his Rf8 is developed, and it faces all the White pieces alone.)> I'm not sure what you mean by "material is equal." As I look at the board, white is down an exchange after 22. Qxg4. > You are right, and I had failure of board vision. I should have calculated 21...Ng4 further. Unfortunately, after 2 years on CG, I now do get a sense of when a move is "right", and as in my mathematical problem-solving, I unconsciously declare the puzzle "trivial" and move on. It is a character flaw. |
|
| Jul-21-09 | | LIFE Master AJ: <Al Wazir> A complete analysis of your idea. [20...hxg5 21.Qxg5 Ng4 22.Rh3+ Kg8T ; (Or <22...Nh6? ; 23.Rxh6+! , etc. ) 23.Bh7+ Kh8 24.Qxg4 g6 25.Bxg6+ Kg7 26.Bxf7+ Kf6 (<26...Kxf7!? 27.Rh7+, etc.) 27.Rh6+ Ke7 28.Rxe6+ Kd7 29.Rg6+ Ke7 30.Qg5+ Kd7 (Or <30...Kxf7 31.Rg7+ Ke8 32.Qg6+) 31.Qf5+ Kc7 32.Qe5+ , and mate next move. ] |
|
| Jul-21-09 | | LIFE Master AJ: <Al Wazir> I agree with you, I am not sure how much Varavin actually calculated here, he probably trusted his intuition. |
|
| Aug-07-09 | | obender71: I saw Qc3 putting the Queen in line with the king but wasn't able to see how to gain something. Completly unable to see Rh7# so forward. Can't visualize well enough the position arised. I really have to do some blindfold exercises. |
|
 |
|
< Earlier Kibitzing · PAGE 2 OF 2 ·
Later Kibitzing> |
Kibitzing
sac: 20.Rbg5