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|May-30-08|| ||hedgeh0g: Got it.|
|May-30-08|| ||johnlspouge: Friday (Difficult): White to play and win.
Material: Down a P. White has a substantial K-side attack based on local superiority in space and material. Only the Black Rg8 defends Kh7, which has one legal move, to h8. White has a battery Rg4 and Rg3 opposite Pg7 and Rg8. The White Ph5 controls the light square g6, while Qf4 and Nh4 can control dark squares around Kh7. The Black Rg8 must defend both Pg7 and Rc8, so Rc8 might become vulnerable to a Q-fork. The White Nh4 is not particularly active yet.
Candidates (29.): Rxg7+, Qxh6+, Nf5
29.Nf5 (threatening 30.Rxg7+ 31.Rxg7+ 32.Qxh6 #)
Black can accept the sacrifice of Nf5.
29…exf5 30.Rxg7+ Rxg7 [Kh8 31.Qxh6#] 31.Qxf5+ Kh8 [or Kg8]
[31…Rg6 32.hxg6+ then 33.Qxc8 and Black drops material]
32.Qxc8+ Kh7 33.Qf5+ Kh8 [or Kg8] 34.Rxg7 Kxg7
[else, drop material or mate]
35.Qf6+ Kf8 [else, 36.h6 and mate soon]
36.h6 (threatening 37.h7 38.h8=Q#]
Black cannot stop Ph6 from h8=Q.
Black must therefore refuse the sacrifice and try to protect g7 against the mate threat.
29…f6 30.Rxg7+ Rxg7 [else, drop Qa7 or be mated]
31.Qxh6+ Kg8 32.Rxg7+
and mate follows.
|May-30-08|| ||jovack: Easy.
A powerful move. Chases the knight off its powerful b4 outpost, and prevents another loss of a valuable pawn since material is the most mathematical way to evaluate chess, and math doesn't lie.
This also prepares our pawn for an eventual promotion after we clear up the queenside, since it is now one step closer.
Too easy for friday, I got this one, like really fast, before I even turned on my computer. 5/5
|May-30-08|| ||johnlspouge: Toga gives value +1.38 to
29…exf5 30.Rxg7+ Rxg7 [Kh8 31.Qxh6#] 31.Qxf5+ Kg8 32.Qxc8+ Kh7 33.Qf5+ Kg8 34.<Rc3>
but I forgot the Ph6 blocks the immediate threat h8=Q, so my 34.Rxg7 fails.
|May-30-08|| ||aragorn69: <patzer 2> The whole point of the puzzle is seeing that, in the final position and after 31.-Rxg7, the tempting 32.Qxc8+? doesn't win because of 32.-Kh7 33.Qf5+ Kg8!|
In other words, to solve the puzzle, one has to see the "liberation" of the h-pawn through 32.Qf6! Rg8 33.Qxh6+ Rh7 34. Qf6+ Rhg7 (or 34.-Rgg7 35.Qd8+) 35.h6!
|May-30-08|| ||ounos: Duh. Close, but not enough. I saw all the way to Qxh6+ Rh7 Qf6+ Rhg7, but I missed the final move to win, 35. h6.|
|May-30-08|| ||znprdx: znprdx: Wow what an irony Black’s 28th move permits White to unleash the attack 29.Rxg7 + Rx[R]g7 30.Nf5!! threatening everything – especially Qxh6|
if e6x[N]f5 31. Qxf5+ assuring the capture of what is now a loose rook – oops and mating (... a sweet point is if Black plays Kh8 White can even be artistic and play Qf6)
This is an exceptional training position – the useful vs. the useless knight
If this starts with a queen sac I may have to box my pieces once and for all :)
I timed out – spending way to much effort on g6 –visualizing a combo with the Queen mating on h3. I finally tried by moving the pieces to see if there was more than by eye could see - and I admit I was a little fuzzy and uncertain as I found 30....Rg5 instead of the knight capture. But 31. Nxh6! and all is well: time to look.....
....go figure: I'd rejected the immediate Nf5 because I thought Kh8 would hold long enough to get in Nd3, but it seems that Rxg7+ works out to the same result?.
|May-30-08|| ||patzer2: <araqorn69> Indeed, after 31...Rxg7, the strongest and only continuation leading to an immediate forced mate is 32.Qf6! |
Yet, even with <the tempting 32. Qxc8+> !?, White appears to still have a winning edge after 32. Qxc8+!? Kh7 33. Qf5+ Kg8 34. Rc3! Kh8! 35. a3! . However, it is not as strong or clear a win as the forced mate with 32. Qf6!
|May-30-08|| ||lost in space: A lot of candidate moves.
I have a shorter look to Qf6, Rg6, Rxg7 and Ng6, but none of them worked out.
I think the solution starts with 29. f5!. Threat: xg7 with mate. So 29...exf5 is the only move for Black.
30. xf5+ Black has 2 options, both not enough to survive:
A. 30...h8 31. xg7 xg7 (or mate in one) 32. f6! and Black is lost (either on g7 or h6, depending on blacks answer). I haven't checked the option 32. Qxc8 as Qf6 is much more forcing.
B 30...g6 31. fxg6 xg6 32. xg6 33. xg6+ h8 34. xh6 h7 35. f6+ and mate in a few moves.
Had no chance to solve the puzzle earlier as it was not possible to access the website in the morning (in Europe)
|May-30-08|| ||JG27Pyth: <In other words, to solve the puzzle, one has to see the "liberation" of the h-pawn through 32.Qf6! Rg8 33.Qxh6+ Rh7 34. Qf6+ Rhg7 (or 34.-Rgg7 35.Qd8+) 35.h6!>|
Yes... but we've come all this way might as well go to mate --
35...Qa6 37.hxg7+ Kh7 38.Rh3#
Omg. I solved this puzzle! And to think it only took me a little more than an hour moving the pieces set up on a board -- we're not playing touch move, are we? ;)
I worked out all the sac declines too, I think 29...f6 is best for black, but white can easily get to a won Q + N and pawns, v R + N and pawns ending. Does anyone see a line quickly forcing to mate after 29...f6?
|May-30-08|| ||Jimfromprovidence: It took a long time to come up with a good defensive play for black on his 28th move. I think 28…Qe7 looks pretty good. It keeps the white queen from getting to that f6 square. |
click for larger view
White’s best line might now be 29 a3 Nc6 30 Nf5 Rc1+ 31 Qxc1 exf5 and white is up just a rook for a knight and pawn.
click for larger view
|May-30-08|| ||xKinGKooLx: 4/5. This one was definitely <difficult.> I got it exactly right, but it took me about 15 minutes of thought. It makes up for not getting yesterday's puzzle though.|
|May-30-08|| ||newzild: I missed 35.h6 in the main line. Damn!|
|May-30-08|| ||YouRang: I finally got this after working through a lot of trial & error.|
Looking at the position, it was clear that I had superior K-side firepower, but black's pawns completely restricted my Q and N from making offensive progress and his R+K otherwise provided adequate protection of g7.
Such conditions scream for a sacrifice to bust his pawn defense and then find the winning continuation. Usually, the best sac is one that allows our Q to join the attack *with check*.
I started out with 29.Rxg7+, etc., which looked promising since my Q comes to f6 with check, leaving me trying to win with Q+N. However, the black king always escapes by running to the Q-side.
So, I backed up and noticed another promising idea: Sac the knight on f5!
29.Nf5 <puts another attack on g7, forcing...> exf5 <and again, allowing my Q to attack with check>
30.Qxf5+ <This is better: My Q has access to both f5 and f6, I still have both rooks, my e pawn is mobile, and black's K has no path to the Q-side. Black only has...> Kh8 <30...g6 31.hxg6 leads to R exchanges with Q+R vs naked K. But now the K is vulnerable from both f6 and h6>
The rest flows pretty naturally (which is fortunate since I'm on the edge of my board vision already).
31.Rxg7 <threat:Qh7#> Rxg7
32.Qf6 <pinning the rook and threatening Ph6, let alone Qxg7#> Rg8 <only way to prevent mate>
33.Qxh6+ <another defender gone, and now my h-pawn is mobile> Rh6 <forced>
34.Qf6+ <black has no time to breathe> Rhg7 <now the rook is pinned again; if 34...Rgg7 then 35.Qd8+ w/ mate next>
35.h6! <and black looks around the board for more defenders, but they're all too far and too few>
|May-30-08|| ||kevin86: I missed this one. I was looking at queen and rook sacs but missed the knight sac at f5. I did get the proper conclusion as pointed out by <YouRang>. (Never argue with a seven foot butler).|
|May-30-08|| ||zenpharaohs: Jimfromprovidence: "It took a long time to come up with a good defensive play for black on his 28th move. I think 28…Qe7 looks pretty good. It keeps the white queen from getting to that f6 square."|
28 ... Qe7
is the only way for black to avoid catastrophe. It plays out
28 ... Qe7
29 a3 Nc6
30 Nf5 Rc1+
31 Qxc1 exf5
32 Rf4 Qd7
click for larger view
Black is down a bit, but the fire on the king side is extinguished.
|May-30-08|| ||MiCrooks: I think it is interesting the number of people that went astray here. I guess they finally gave a challenging enought problem. Or is it just that your chess computer has a hard time finding the win here as it is beyond the horizon unless you let it sit for a while :)!|
After Nf5 it is a forced mate if Black takes the Knight, so arguing over alternative moves or move orders is pretty silly. Also, Qxf5 is the only good move here...again it forces mate whereas playing Rxg7 here only leads to a draw at best.
But even funnier is that Nf5 forces mate REAGARDLESS of black reply!! If you leave the Knight there then Rxg7+ becomes crushing against most other replies. The point being that after Rxg7 Qxh6 is crushing. And trying to block the file by g6 or g5 fails to hxg6+ with mate still coming.
Given the way the week was going I started by trying to set up a mating position with the King stuck on the h-file and sacking to mate with a rook, but when that lead nowhere Nf5 became clear. I think it's a pretty incredible position really. It is rare that you find a position like that where you can force mate with a quiet move like Nf5!
|May-30-08|| ||johnlspouge: <<MiCrooks> wrote: Also, Qxf5 is the only good move here...again it forces mate whereas playing Rxg7 here only leads to a draw at best.>|
According to Toga II 1.3.1,
<<johnlspouge> wrote: Toga gives value +1.38 to
29…exf5 30.Rxg7+ Rxg7 [Kh8 31.Qxh6#] 31.Qxf5+ Kg8 32.Qxc8+ Kh7 33.Qf5+ Kg8 34.<Rc3>>
Thus, 30.Rxg7+ probably wins as well, although I agree it is not as good as 30.Qxf5+.
|May-30-08|| ||Marmot PFL: Didn't spend too much time on it and didn't see the mate coming, and neither did black. Like many games in the French black wins a pawn on the queen side but all it takes is one mistake to lose on the king side.|
|May-30-08|| ||DarthStapler: I didn't see it|
|May-30-08|| ||234: Thursday puzzle <25. ...?> May-29-08 S Narayanan vs V Ikonnikov, 2006|
|May-30-08|| ||JG27Pyth: Well, after a refreshing break I worked out Black declining the sac with 29...f6 (revising earlier comment that said black could at least fight to losing endgame... that is incorrect) and it doesn't end well for black ... it forces to mate pretty quickly:|
...30.Rxg7+ Rxg7 31.Qxh6+ or,
...30.Rxg7+ Qxg7 31.Rxg7+ Rxg7 32. Qxh6 with 33.Qxg7# to follow.
Black can't decline the sac... ergo: Nf5 forces mate, wow.
|May-30-08|| ||vangogh228: Came up with the same solution as JG27Pyth. Mate on move 37 with Ra3#.|
|May-30-08|| ||Magic Castle: 30. ...Rg7. It is easy to get wrong with 31. Qc8+ Kh2 32. Qf5 Kg8 and one only gets a perpetual check. The move 31. Qf6 is brilliant considering the tempting but poisoned rook at c8.|
|Feb-15-12|| ||BlackSheep: I was running through the game thinking this would make an interesting puzzle and lo and behold it has been (nearly four years ago granted) .|
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