< Earlier Kibitzing · PAGE 3 OF 3 ·
|Jun-19-07|| ||patzer2: For today's puzzle solution, the passed pawn combination 28. d5+! wins.|
|Jun-19-07|| ||patzer2: Losing immediately for Black was 27...Nxh3? Instead 27... Ng6 28. d5+ Kxc5 29. d6 Nf8 = at least stops the 28. d5+ Queening combination. |
However, after 27...Ng6 28. Re1 b3 29. Nb3 White probably still has a winning advantage.
|Jun-19-07|| ||Kleve: This is almost exactly like a correspondence game I recently played... I will have to find the game score. Similar situation... My opponent got greedy and took a rook, allowing a pawn advance with check and an undisputed queen a move or two later. Man, that felt good!|
|Jun-19-07|| ||nimzo knight: <gilmoy: [A] Black's N is close to 'no escape': 28.Kg7 Rh6 29.Rh1 but Rxc5 30.dxc5 Ng5 and Black's K will recover some pawns, with a laborious endgame for White.>
I think u meant 28. Kg2, easier escape for black is 28..Nf4+.|
|Jun-19-07|| ||Frank Heller: I think it is fair to call Ulf Andersson an endgame specialist.|
|Jun-19-07|| ||Crowaholic: I first tried to trap the knight with Kg2 (after some Zwischenzug, e.g. 28. Ne4), couldn't make it work, and then noticed that Black gets killed by the simple pawn push 28. d5+ if he takes the knight. I tried a little harder and found 28. ..Kc7 29. d6+ Kd8 30. Nxb7+ Kd7 31. c5 and this just smells like a White win.|
<MostlyAverageJoe> Why waste the c4 pawn?
29. ..Rxg3 30. fxg3 Ng5 31. Rd5+! Kc6 32. d7 Ne6 33. d8=Q Nxd8 34. Rxd8
If 31. ..Kxc4 then queening is inevitable because of 32. Rxg5.
|Jun-19-07|| ||YouRang: Got it, after spending a few moments looking for mate or a rook trap.|
It took a while to realize this was a knight-sac promotion tactic with 28. d5+!
Black can either:
(1) take the knight, allowing the pawn to sprint freely to the endzone, or
(2) retreat until the pawn gets to d7, and then it promotes anyway since the knight can guards the pomotion square with Nxb7!
(3) chase the pawn with the rook (i.e. 28...Re5), and find that the rook is a step too slow.
|Jun-19-07|| ||Grampmaster: How rusty we get after being out of action two months with some very serious surgery.|
|Jun-19-07|| ||kevin86: I once heard that a passed pawn supported by a rook and knight is about as good as it gets. Here,with the above criteria AND black's pieces out of position--the only thing left to do is PUSH THE PAWN.|
Of course 28...♔d6 falls to 29 ♘e4+ winning the rook..
the pawn goes marching on...(to the tune of the Battle Hymn of the Republic)
|Jun-19-07|| ||playground player: Saw d5+ at once, and then wasted time looking for something more complicated because the answer seemed too easy to be true. But it is true!|
|Jun-19-07|| ||Justawoodpusher: Got it. I wonder if the pawn pushing theme will continue this week.|
|Jun-19-07|| ||WarmasterKron: I got this fairly quickly.
<Crowaholic> Of course, if White has a sense of humour, after 32...Ne6 in your line, White can rub salt in the wound with 33.d8N+.
|Jun-19-07|| ||schnarre: Right up Black's nose!|
|Jun-19-07|| ||newton296: d5+ and black's got no way to prevent promotion. Interesting all the post saying black can stop the promotion in the line d5+ ...kxc5 d6 with the desparate rook sac rxg3 ?? I can't believe anyone looked at this line that deep as it's clearly losing but props for finding it!!|
|Jun-19-07|| ||fm avari viraf: Every body seems to be happy [& why not]finding the right move. White's d-pawn turns out to be a big menace as Black will have to part with more material from stopping it.|
|Jun-19-07|| ||Sacrificator: Nimzowitch adviced: "Passed pawns must be pushed." This pawn at d4 can't be stopped any more without material loss.|
|Jun-19-07|| ||soberknight: I saw the solution, but I'm still amazed that it works. Such a clear path to the queening square with such a profusion of material still on the board is nearly unheard of. It reminds me of one of Capa's classic victories in the QGD.|
|Jun-19-07|| ||Fezzik: Ok, so this is easily winning for White.
But this is Ulf Andersson winning. No way in the world is this worth only 1.5 stars. 1.5 stars should rank as one of the easiest puzzles, yet the solver has to recognise the importance of the passed pawn and to make sure there are no bizarre ways to stop the pawn from queening.
This would include working out 28.d5!! Kc7 (28...Kd6 Nd5+) 29.d6+ Kd8 30.
Nxb7+ (better than 30.d7 because of Rxc5)Kd7 31.c5!
That's a tremendous amount to analyse for only 1.5 stars. Especially since all this wins because the Nh3 is trapped but White can't attack it with Kg2 (...Nf4+!).
|Jun-19-07|| ||MostlyAverageJoe: <Fezzik: No way in the world is this worth only 1.5 stars.>|
I agree. I did not have time to run analysis with Hiarcs until just now, but once I did, the depth of computation required to justify the knight sacrifice is comparable to Thursday-level puzzles.
However, for humans this puzzle might be an easier task, as recognition of a promotable pawn should prompt one to concentrate the analysis on that line. Computer engines still cannot quite focus that sharply, I think.
<newton296: ... the desparate rook sac rxg3 ?? I can't believe anyone looked at this line that deep as it's clearly losing> Well, the need to look at this line comes from simple math. It takes 4 moves for the pawn to promote. Black will waste one move to get out of check. If g5 square were free, the knight can get to d8 in 3 moves, for the total of 4 moves to grab the promoted pawn.
As a matter of fact, the above calculation prompted me to look at 28.Ne4 as a possible alternate winning line. I did not quite like Ne4 after black's Rh5 (I did not see another good one, Ra5), and returned to the pawn promotion idea (today Hiarcs tells me that it is also advantageous for white, but nowhere as good (+1.75, 18-ply).
Note that if black had one extra tempo, he could plant the knight in front of the d pawn, making the win for white much more difficult. The resulting position:
click for larger view
evaluates at +1.46 (18-ply), which is worse for white than 28.Ne4.
The interesting twist to the rook sac is that if white ignores it and keeps pushing the pawn, black will win (see my first post). Finally, Hiarcs confirms that the rook sac turns out to be the line where black can offer most resistance to white, futile as it may be :-)
<Crowaholic: <MostlyAverageJoe> Why waste the c4 pawn?> Good variation, indeed. However, the waste is not a big deal here - if black king takes c4, white will obliterate the 7th rank and still promote one of his pawns.
|Jun-19-07|| ||actionhero56: this is easiest puzzle i've solved|
|Aug-15-07|| ||xeroxmachine: Haha, Horberg!? It should be Hörberg.
Horberg means Hookermountain in swedish.
|Aug-15-07|| ||keypusher: <xeroxmachine> How do you pronounce the o-umlaut in Swedish? German names with an o-umlaut are frequently spelled with an extra e in English (Goering, Gruenfeld) because we don't use umlauts.|
|Aug-15-07|| ||SwitchingQuylthulg: <keypusher> it's "Ö", not "o-umlaut". Check http://en.wikipedia.org/wiki/%C3%96|
|Aug-15-07|| ||keypusher: <SQ> Aha, thanks, I didn't know that. So Book didn't really have a double umlaut.|
|Sep-06-07|| ||xeroxmachine: Ö is pronunced like the "ea" in heard or like the "i" in bird. Like this, Hörd and börd.|
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