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|Dec-27-08|| ||Samagonka: It's not surprising how many got this right. It was a good Saturday puzzle. Not too difficult for the weekend.|
|Dec-27-08|| ||agb2002: 26.Rxg6+ hxg6 27.Qxg6+ Qg7 28.Qe6+
A) 28... Qf7 29.Rxf7 Rxf7 30.Be5 followed by the advance of the king’s side pawns.
B) 28... Kh7 29.Be5
B.1) 29... Rxf3 30.Bxg7 Rxc3 31.Qf7 threatening Bf8+ and Be5+,Bf4+.
B.2) 29... Qh6 30.Rf7+ Kg8 31.Rg7+ Kh8 32.Qxh6 mate.
B.3) 29... Qg6 30.Rh3+ Qh6 31.Rxh6 mate.
B.4) 29... Qxe5 30.Rh3+ Kg7 31.dxe5 with a winning attack.
C) 28... Rf7 29.Be5
C.1) 29... Qh7 30.Rg3+ Kf8 31.Bd6+ Re7 32.Rg8+ Qxg8 33.Qxe7 mate.
C.2) 29... Qxe5 30.Qxf7+ Kh8 31.dxe5 winning.
C.3) 29... Rc6 30.Qe8+ Qf8 31.Rg3+ Kh7 32.Kg7+
C.3.a) 32... Rxg7 33.Qxf8 Rg4 (33... Rg8 34.Qh5+ Rh6 35.Qf7+ Rg7 36.Qxg7 mate; 33... Rg5 34.Qh8+ Kg6 35.Qg7+ Kh5 –35... Kf5 36.Qf7+ mate in three- 36.Qh7+ Rh6 37.Qxb7) 34.h3 with a winning attack.
C.3.b) 32... Kh6 33.Qxf7 Qxf7 34.Rxf7 with a won endgame.
C.4) 29... Rcf8 30.Bxg7 Kxg7 31.Rg3+ Kh8 32.Qh6+ Rh7 33.Qxf8 mate.
I think that’s all.
|Dec-27-08|| ||Eisenheim: Is the refutation of 29 Be5, merely 29...Rc6, evening the exchange? 29 Bd6 allows the tempo to capture the Queen and give the winning position.|
|Dec-27-08|| ||agb2002: Another botched job: the rook on f7 was pinned in so many variations that I thought that 30... Rf8 in my line C.3) was impossible!|
|Dec-27-08|| ||melianis: Well, that was brutal, only after checking the correct answer I realised 31.Rg3 (of course!) gets the queen and supports 35.Bf4+. Pondered the continations after Be5, as many have done.|
|Dec-27-08|| ||dukesterdog2: If not for the need to find the critical 29.Bd6 (which I missed as well) this would probably be a Wednesday puzzle. The first three moves didn't seem too difficult to find.|
|Dec-27-08|| ||znprdx: um-er-ah ....28.Kh7 29.Be5
Rx[R]f3 would almost be a spoiler at least in Blitz 30. Bx[Q]g7
Alternatively 29.Rx[R]f8+ Rx[R]f8 30.Be5 Qg6 :)
Put me in the 26. Be5 camp ...Keep it simple - it wins quietly (given the passed 'd' pawn) or perhaps more elegantly than the text even if ...Rc6 (Rc7 may be better)
e.g. 27.Rh3! threatening Rxg6+
....Nd5 28. Rxg6 anyway! h6x[R]g6 29.Rh8+ Kf7 30.Rh7+ Ke6 31.Rx[Q]d7
Perhaps this entertaining: ...Rx[R]f1+ 32. Kx[R]f1 Ne3+ 33.Ke2 Nx[Q]c2 34.Rxb7 I'd welcome feedback.
Bd6 seems rather ponderous - despite its ultimate efficiency (quite fascinating) but I doubt it was even considered at the moment Rxg6+ was played: which was “sufficent” to win...but with little “beauty” nor “surprise”
|Dec-27-08|| ||johnlspouge: Saturday (Very Difficult)
Huzman vs Dreev, 1987 (26.?)
White to play and win.
Material: B for N. The Black Kg8 has 2 legal moves, both dark squares under White control after Bg3-e5. All White pieces are active, with Rf3 facing the Black Rf8, while Qc2 and Rg5 attack Pg6. No Black pieces are loose. Black has no counterattack and is essentially a piece down, with Nb6 out of play. The White Kg8 is secure, though open on the back rank and b8-g1 diagonal.
Candidates (26.): Rxg6+
26.Rxg6+ hxg6 [else, 29.Be5+ and mate soon]
27.Qxg6+ Qg7 [Kh8 28.Be5+ and mate soon]
Throughout the following, although Black is up R+N for B+2P, if he drops Q for R or B, he has a lost endgame:
(1) 28…Kh8 29.Be5 then 30.Bxg7
(2) 28…Qf7 29.Rxf7 Rxf7
Thus, there is only one option, which now burdens Qg7 with protecting Rf8:
<[Here I went wrong with 29.Be5, which permits the defense 29…Rc3, and White loses, with Toga evaluating White at worse than -1.0 P. The game continuation 29.Bd6 was critical.]>
|Dec-27-08|| ||johnlspouge: Hi, <dzechiel>. Our communication on CG seems to be more dependable than regular email :) The answer is "yes": I received your email and attachment just fine. Many thanks for the correction.|
Although I went down in flames today, I can take solace in the fact that it might be my first time seeing this puzzle, which was also puzzle of the day on Aug 10, 2007. You liked 29.Be5 back then, too. We had better remember this one... ;>)
Hi, <znprdx>. You are correct that 26.Be5 wins. Toga II 1.3.1 evaluates it as follows. (Humans can improve near the end of the complete computer variation.)
[ply 17/71 time 13:21 value +2.09]
26.<Be5> Rxf3 27.Rxg6+ Kf8 28.Bd6+ Kf7 29.Rg5 Qxd6 30.Qxh7+ Ke6 31.gxf3 Rf8 32.Kg2 Qf4 33.Re5+ Kf6 34.Re4 Qd2+ 35.Kh3 Nd5 36.Qh4+ Qg5 37.Re6+ Kxe6 38.Qxg5 Rxf3+ 39.Kg4 Re3 40.Qf5+ Kd6 41.Qg6+ Re6
Interestingly, the valuation is near 0 before ply 17, so the winning potential of the move is unusually deep.
|Dec-27-08|| ||johnlspouge: < <Eisenheim>: Is the refutation of 29 Be5, merely 29...Rc6, evening the exchange? 29 Bd6 allows the tempo to capture the Queen and give the winning position. >|
Having pondered the position along with trusty Toga, I now understand the puzzle as follows. At move 29, White needs to <clear> g3 for Rf3, to pin and win the Black Qg7 with 30.Rg3. Where Bg3 actually goes is immaterial to the threat of 30.Rg3, which has an immediacy of "I will get your Q for my R." The defense 29.Be5 Rc6 is tactically adequate, however: it responds "I will get your Q for my R first."
The real point, however, is that 29...Rc6 is a <strategic> win: it activates Rc8 for defense, giving Black adequate defensive resources against the White attack. White foils the strategically adequate defense with 29.Bd6, rendering the tactical immediacy of 29...Rc6 inadequate: "I will get your B for my R." Although the game move 29...Rf8 makes 30.Be5 superior to 30.Rg3 (Toga indicates 29...Nd7 was better than 29...Rf8), execution of the underlying threat 30.Rg3 would still have won handily.
|Dec-27-08|| ||braimondi: First time I solve a very difficult problem!|
|Dec-27-08|| ||MiCrooks: The try Rxg6+ jumps out at you, so that were it not for the Knight defending the c8 Rook this would be a Tuesday problem or Wednesday at best.|
What makes it harder is the move that all have discussed - Bd6 instead of the tempting Be5. It is clear that the Bishop needs to move since you have invested a Rook already and you need to be able to bring the Rook to g3 and possibly h3 depending on the defensive replies.
You really WANT your bishop on e5, BUT you also HAVE to maintain the pin on f7 so noting that Rc6 will break that pin you have to play Bd6 so as to have time to play Rg3 while maintaining the pin at f7.
I have not dropped this into a computer yet, so I do not know if Rf8 was the best defensive try. I guess the idea is that once the Rook moves Black has mate in one floating around at f1 that White will have to eventually counter. That and that in the end game with Q vs 2R you typically want the rooks in some sort of battery. But here it leads to a forced loss so maybe there was some better try?
|Dec-27-08|| ||MiCrooks: Well, looking with the computer it appears that Rf8 was not the best move, but it still might have been the best practical try. Sure in the end the battery at f7/f8 helped White with his mating net, but other moves, while perhaps slightly better (Nd7 being the best alternative) really offer no practical chances in the ensuing endgame.|
|Dec-27-08|| ||MostlyAverageJoe: <johnlspouge: ... Hi, <znprdx>. You are correct that 26.Be5 wins. Toga II 1.3.1 evaluates it as follows.... [ply 17/71 time 13:21 value +2.09] |
26.<Be5> Rxf3 ...>
Alas, it is not certain that that 26.Be5 wins. Rxf3 is not forced, and it might be better for the black is to protect the g6 pawn:
and the evaluations stay under +0.70, quite far from an assured win, with two best continuations for white (explored forward, backslid, then 18-ply deep):
1. (+0.64) 27. Rxf8 Kxf8 28. Rg3 Re6 ...
2. (+0.64) 27. Rgg3 Rxf3 28. Rxf3 Re6 ...
The position is still very complex, though, but the valuation drops towards zero with increasing depth -- not a good sign for white's hopes of winning.
|Dec-27-08|| ||al wazir: <dzechiel: <sigh> From reading the notes I can see . . .>|
If you read *all* the notes, you will find these (dated 8/10/07):
<Difficult. White to move. Material even. White's bishop is better than black's knight. g6 is a weak point to consider. So, what's our plan?
Right away you want to play 26 Rxg6+, and that does look promising . . . . 26 Rxg6+ Kh8 27 Be5+ ouch . . . 26 Rxg6+ hxg6 27 Qxg6+ Qg7 . . . 28 Qe6+ Rf7 . . . 29 Be5 Qf8 . . . This seems pretty straight forward to me. Time to check. . . . Close, but no cigar. I'm not sure I understand the importance of 29 Bd6 instead of 29 Be5 right away.> ( I have taken the liberty of deleting some extraneous material.)
The kibitzer? One whose handle is quite familiar to you: <dzechiel>
No doubt I also looked at this puzzle the first time it ran and failed to find the correct solution. But -- luckily -- I only posted once.
|Dec-27-08|| ||dzechiel: Hey, at least I'm consistent! And don't let anybody accuse me of peeking... :D|
|Dec-27-08|| ||johnlspouge: < <MostlyAverageJoe> wrote: <johnlspouge: ... Hi, <znprdx>. You are correct that 26.Be5 wins. [snip] it might be better for the black is to protect the g6 pawn:|
26.<Be5> Rc6! >
Yes, given enough backsliding, Toga agrees. The White win depends on a successful sacrifice Rxg6. Because the lift Rc8-c6 prevents the sacrifice, it leads to a clear draw.
|Dec-27-08|| ||Zzyw: I almost got this one. I spotted how 29.Be5? Rc6! failed and then abandoned 26.Rxg6+! altogether, tried to make other moves work and gave up:(|
|Dec-27-08|| ||whiteshark: Wow, the Huzman really played <26.Rxg6+>. My line was <26.Be5 Rxf3 27.Rxg6+ hxg6 28.Qxg6+ Kf8 29.Bd6+> and black have to give up the queen.|
|Dec-27-08|| ||zdigyigy: Not only blocking the sixth rank the bishop also covers f8, keeping the pin alive on the king. What a powerful analysis to make over the board, especially against Alexy Dreev.|
|Dec-27-08|| ||MostlyAverageJoe: <MostlyAverageJoe:
1. (+0.64) 27. Rxf8 Kxf8 28. Rg3 Re6>
Update: 20 plies at the end of the above drops the eval to +0.54.
1A. (+0.54) 29. Rf3 Kg8 30. Qe4 Re8 31. Qf4 Qe7 ...
1B. (+0.53) 29. Qc1 Kg8 30. Rf3 Qe8 31. Qf1 Re7 ...
|Dec-27-08|| ||patzer2: For today's Saturday puzzle solution, White's demolition combination with 26. Rxg6+!! initiates a decisive King side assault.|
|Dec-27-08|| ||njchess: Like most, I got the first three moves for White. However, I then played Bd6 over Be5 because I wanted to follow up with Rg3 and I thought that Bd6 would prevent Black from playing Kf8 at some point (I was also worried that Qxe5 might secure a draw for Black). It wasn't until I played Bd6 that I realized my queen was protected from Rc6! Once Black seals off the f-file with Rf8, the rest is forced.|
|Dec-27-08|| ||beginner64: Seems like a Thursday level to me. I got all the way till Bd6 (favoring it to Be5 to check flight square f8). Most of you have said somethings to this effect.|
|Jan-03-09|| ||zenpharaohs: Stop me if I've told this one before...|
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