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| Mar-21-09 | | stacase: Darth,
I think this entire week has been easy. |
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| Mar-21-09 | | mmufa: Yesterday's puzzle anyone? - thanks |
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| Mar-21-09 | | goodevans: My bad run of form for the week continues. The first two moves were pretty obvious and I could see that 17 Qb3 won quickly against both 16 ... Kf8 and 16 ... Kg8, but 16 ... Kf6 was where I came unstuck. I was beguiled by the prospect of a mating net with 17 Qd4+ Kf5 18 g4+ and saw as far as 18 ... Kxg4 19 f5+ Kh5 20 Qd1+ Kh4 21 Rg1 when I reached the edge of my "calculation horizon" convinced that black was hopeless. What I'd missed, of course, was 19 f5+?? Bxd4. I'm putting all this down to a bad head cold and expecting better of myself when I've got rid of it! |
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| Mar-21-09 | | goodevans: I see that <Once> seems to have fallen into the same trap as me. 16 ... Kf6 17 Nxh7+ is the right way to bring about a quick win as others have already pointed out. |
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| Mar-21-09 | | Once: <goodevans: I see that <Once> seems to have fallen into the same trap as me. 16 ... Kf6 17 Nxh7+ is the right way to bring about a quick win as others have already pointed out.> Not so fast, my friend!
Fritz 11 rates 16...Kf6 17. Qd4+ as +6.49 and 16...Kf6 17. Nxh7+ as +4.29. For my money, I prefer the Qd4+ line as it centralises the queen and keeps the knight on the aggressive g5 square. Grabbing the cheap h7 pawn just doesn't seem to be in the spirit of the position. Either move wins, so there is no such thing as "the right way" from this position. |
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| Mar-21-09 | | WhiteRook48: missed it |
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| Mar-21-09 | | johnlspouge: Saturday (Very Difficult)
I Yagupov vs A Korotylev, 2002 (15.?) White to play and win.
Material: Up a P. The Black Kg8 has 2 legal moves, both dark squares on the back rank. The Black Kg8 is insecure: 15.Bxf7+ opens Kg8 for an attack on the light squares. The Black Re8 pins the loose Be3 to Ke1, a threat of capture with check that White must consider. White has an advanced Pd6 ready to capture Pc7, which Qc8 protects. The Black Qc8 has 2 other defensive duties, protecting Bb7 and Nd7. The White Qd1 attacks Nd7 indirectly, obscured by Pd6 and Bd5 (which can capture Bb7), so a clearance combination on the d-file to exploit the overburdened Black Qc8 enters (brief) consideration also. Candidates (15.): Bxf7+
15.Bxf7+ Kxf7 [else, 16.Bxe8]
Candidates (16.): Qb3+, Ng5+
White can play the candidates in either order, but 16.Ng5+ permits Black 16…Kg8, an extra way to go wrong, and leaves the option 17.Qd4+ open. 16.Ng5+
(1) 16…Kg8 17.Qb3+ Kh8 [Kf8 18.Qf7#]
18.Nf7+ Kg8 19.Nh6+ Kh8 [Kf8 20.Qf7#]
20.Qg8+ Rxg8 21.Nf7#
Black can throw pieces, but cannot avoid the above mate (called “Philidor’s Legacy”). <[Toga II 1.3.1 confirms that <dzechiel>'s variation 17…Re6 permits Black to avoid mate, but not loss.]> (2) 16…Kf8 17.Qb3 (threatening 18.Qf7# or 18.Nxh7#)
Other than useless interpositions, Black has 2 options: (1) clear e8 or g7 as a flight square, or (2) die. 17…Rxe3+ 18.Kf2 Re2+ [Re7 29.dxe7+ Kxe7 30.Qe6+ and mate-in-1] 19.Kxe2 Qe8+ 20.Kd2 Bf6 [Bh6 is worse]
21.Rae1 (threatening 22.Rxe8+ or 22.Qf7#)
21…Ne5 22.Kc2 (threatening 23.Nxh7+ 24.Nxf6 then 25.Rxe5 or 25.fxe5+) White has both positional and material advantage.
<[Toga prefers my 20.Kd2 to the game variation 20.Kf2, although I did not analyze the game response 20…Nf6.>] (2) 16…Kf6 17.O-O (threatening 18.Bd4+ and mate soon) <[Toga gives 17.Qd4+ immediately as much better than 17.O-O c5, which still wins easily for White, so I delete the rest of my variation.]> |
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| Mar-21-09 | | johnlspouge: To me, the most instructive part of the combination is 17.Qb3, where White permits his K to receive check, the better to damage the Black Kf8 with immediate mate threats. I am surprised that nobody has commented, because I suspect an inexperienced player would hesitate to place his K in such "danger". |
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| Mar-21-09 | | goodevans: <Once: ... Fritz 11 rates 16...Kf6 17. Qd4+ as +6.49 and 16...Kf6 17. Nxh7+ as +4.29. ... Grabbing the cheap h7 pawn just doesn't seem to be in the spirit of the position.> Point taken, although 17 Nh7+ isn't just a pawn grab. It nets a whole rook a few moves later. To me, at least, even though it evaluates better 17 Qd4+ Kf5 is less clear. I wouldn't be certain whether to play the immediate 18 Qxg7 or whether to play 18 g4+ Kxg4 19 Rg1+ first. ... Or maybe it's neither of these. Perhaps you could oblige. |
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| Mar-21-09 | | Once: <goodevans> Okay, let's see if we can clear this up. 15. Bxf7+ Kxf7 16. Ng5+ Kf6 17. Nxh7+ Ke6 leads to this position ... 
click for larger viewI don't see how white is going to win a rook from here. Indeed, the best line may be to play 18. Ng5+ Kf4 19. Qd4+ and transpose to the line that I favoured. Let's try the other white approach. Here's a sample line from Fritz. Not forced, but pretty emphatic I think: 16... Kf6 17. Qd4+ Kf5 18. Qd3+ Kf6 19. O-O cxd6 20. Qxd6+ Kf5 21. Qd3+ Kf6 22. Bd4+ Ke7 23. Rae1+ Be5 24. fxe5 
click for larger viewWhite has a fantastic position. Now I wouldn't quibble with 17. Nxh7+ as a viable winning move. But I still can't see how 17. Qd4+ is falling into a trap. |
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| Mar-21-09 | | TheChessGuy: 15.Bxf7+! is just one of those moves that I find hard to resist playing. 17.Qb3! is an outstanding find. White willingly subjects his king to attack, because he knows that his attack is stronger. Shades of Steinitz! |
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| Mar-21-09 | | goodevans: <Once> Taking several of your points in turn ... From your first diagram ... <I don't see how white is going to win a rook from here.> It wasn't from there that I saw the rook win, but from (the probably weaker) 17 ... Kf7 18 Qb3+ Re6 19 Ng5+. Against 17 ... Ke6, I still like the look of 18 Qb3+ (18 ... Bd5 19 Ng5+) in preference to 18 Ng5+. As for < ... I still can't see how 17. Qd4+ is falling into a trap.>, I think you misunderstood what I meant. In my initial posting I made the mistake of assuming that 17 Qd4+ led to a swift mating net, whereas white's win, whilst emphatic, is a bit more complicated than I'd given credit for. The words of one of your earlier postings, <Now, 16...Kf6 is met by 17. Qd4+ and a sadistic king hunt>, led me to suspect that you'd fallen into the same "trap" that I did in thinking that a straightforward mating net would follow, whereas the analysis you've just posted clearly shows that you saw more than I did. |
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| Mar-21-09 | | DarthStapler: I got the general idea and some of the moves |
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| Mar-21-09 | | AugustAle: <lostgalaxy: Hi>
<"when and where can I see the official solution?"?>
You, and everyone, are the final solution.
This puzzle is another good example.
Read thru the posts and add your own.
Unofficially.... There are several regular excellent contribrs that break it down and bring it home. |
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| Mar-21-09 | | banane: Great explanation <Once>! i love this site!!! |
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Mar-21-09
 | | Jimfromprovidence: I looked at 17… Bxc3+ ?! below. 
click for larger view
Now, if 18 bxc3?, 18…Rxe3+ followed by Qe8 gets black off the hook. However, white has 18 Kf2, forcing black to play 18…Ne5 to avoid Qf7#.
click for larger view
Now, after 19 fxe5 Qf5+ 20 Kg1 black is out of bullets. |
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| Mar-21-09 | | morfishine: Well, I got the first 2 moves right |
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| Mar-21-09 | | whiteshark: <morfishine: Well, I got the first 2 moves right> Me too! |
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| Mar-21-09 | | Once: <goodevans> Like every good saturday/ sunday puzzle, this one reveals its secrets bit by bit ... 15. Bxf7+ Kxf7 16. Ng5+ Kf6 17. Nxh7+ Ke6 18. Qb3+ Bd5 19. Ng5+ Kxd6 20. 0-0-0 c6 and black may well have equalised. |
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| Mar-21-09 | | eaglewing: Another option to resist longer and afford a bit of careful play of White, but obviously due to material advantage it is a win, could be: 20. Kf2 cd 21. Nxh7 Ke7 22. Rhe1 Ne5 23. fe Bxe5 24. Ng5 Qg8 |
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| Mar-21-09 | | agb2002: Black is a pawn down but threatens 15... Rxe3+. The bishop on d5, the knight ready to jump to g5 and b3 immediately available to the queen suggest 15.Bxf7+: A) 15... Kxf7 16.Ng5+
A.1) 16... Kg8 17.Qb3+ Kh8 (17... Kf8 18.Qf7+ or 18.Nxh7#) 18.Nf7+ Kg8 19.Nh6+ Kh8 (19... Kf8 20.Qf7# or 20.Qg8#) 20.Qg8+ Rxg8 21.Nf7#. A.2) 16... Kf8 17.Qb3 (threatening 18.Qf7# and 18.Nxh7#) Rxe3+ 18.Kf2 (18.Kd1 Rd3+ and 19... Bd5; 18.Kd2 Rd3+ 19.Kxd3 Nc5+) A.2.a) 18... Qe8 19.Nxh7#.
A.2.b) 18... Ne5 19.fxe5  .
A.2.c) 18... Ke8 19.Qf7+ Kd8 20.Kxe3 .
A.2.d) 18... Re2+ 19.Kxe2 Qe8+ 20.Kf2
A.2.d.i) 20... Nf6 21.Rhe1 Be4 22.Rxe4 (22... Qxe4 23.Qf7#; 22... Nxe4 23.Nxh7#; 22... Qd7 23.Re7). A.2.d.ii) 20... Bf6 21.Rhe1 (21... Be4 22.Rxe4; 21... Ne5 22.Nxh7+ Kg7 23.Nxf6 Kxf6 24.fxe5). A.3) 16... Kf6 17.O-O
A.3.a) 17... Rxe3 18.Qd4+ Kf5 19.Qxe3 (threatens 20.Qe6#, 20.g4+, etc.). A.3.b) 17... c5 18.Qd3 trying f5.
B) 15... Kh8 16.Bxe8
B.1) 16... Qxe8 17.Qe2 Bxg2 18.Qxg2 Qxe3+ 19.Kd1 Qd3 20.Kc1 Re8 21.Rd1 Qe3+ 22.Kc2 cxd6 23.Rxd6 followed by Rad1 . B.2) 16... Bxg2 17.Qg4
B.2.a) 17... Bxh1 18.Bxd7 .
B.2.b) 17... Nf6 18.Qxc8 Rxc8 19.d7 .
B.2.c) 17... Bxh3 18.Qxh3 (or 18.Bxd7 Bxg4 19.Bxc8) Qxe8 19.O-O-O . B.2.d) 17... Qxe8 18.Qxg2 Qxe3+ transposes to B.1).
C) 15... Kf8 16.Bxe8 is similar to C).
I'm not satisfied with my results, particularly, line A.3) but it's time to post, check and go to bed. |
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| Mar-21-09 | | agb2002: In my line A.3.b) 18.Qb3, threatening 19.Qf7#, is probably much better than 18.Qd3. |
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| Mar-21-09 | | AnotherNN: After 20. ...Nf6, I went for 21.Ne6+. It's good enough to win the Queen, so there. |
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| Mar-21-09 | | CHESSTTCAMPS: I'm getting a look at this rather late on a busy day, but after a short review it looks to be a somewhat easier problem than those of the previous two days. The possibility that white actually has an advantage here might not be obvious from a logical standpoint (certainly not to an untrained eye), given the fact that black has all his pieces developed, is castled, has apparent control of the open e-file with his rook, and is subjecting the white bishop on e3 to a deadly pin. Yet in chess the biggest weakness can undercut a multitude of strengths. In this case, black's weak f7 is an inviting target for a lightning white invasion. An opportunity to execute the familiar Philidor's Legacy presents itself. With the powerful bishop on d5 threatened to be exchanged, white must act immediately with a sacrifice: 15.Bxf7+!
A. 15... Kxf7 16.Ng5+ Kg8? 17.Qb3+ Kh8 18.Nf7+ Kg8 19.Nh6+ Kh8 20.Qg8+ Rxg8 21.Nf7# is Philidor's Legacy. A.1 16...Kf8 17.Qb3! Rxe3+ 18.Kf2 and there is no good defense to the threat of 19.Qf7#, for example: A.1.a 18...Qe8 19.Nh7#!
A.1.b 18...Ne5 19.fxe5 Qd7 20.Nxh7+ Ke8 21.Qg8+ and mate next. A.1.c 18...Re7 19.dxe7+ Kxe7 20.Qe6+ and mate next. A.1.d 18...Re2+! 19.Kf1! (19.Kxe2 Qe8+ gives the defense a vital tempo) Bxg2+ 20.Kxe2 Qe8+ 21.Kf2 and black can't meet all of the threats 22.Nh7#, 22.Kxg2 and 22.Re1. A.2 16...Kf6 17.Nxh7+! Kf5 (....Kf7 18.Qb3+ Ke6 19.Ng5+ wins) 18.g4+ Ke4 19.Ng5+ Kxe3 20.Qd2# There are a few more defensive lines to analyze (including declines of 15.Bxf7+), but I'm confident that white is in control. I will post now (before the puzzle rolls over to Sunday) and see what happened. |
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| Mar-27-09 | | patzer2: White's demolition sacrifice 15. Bxf7+! initiates a decisive attacking combination against Black's weak castled King position, and it also solves the Saturday March 21, 2009 puzzle. Here's my computer checked analysis:
<15. Bxf7+!! Kxf7 16. Ng5+ Kf8> If 16... Kf6, then White wins after 17. Qd4+ Kf5 18. g4+! Kxg4 19. Rg1+ Kf5 20. Qd3+ Re4 21. Nxe4 Bxe4 22. Rg5+ Kf6 23. Qxe4 . <17. Qb3 Rxe3+ 18. Kf2 Re2+ > If 18... Re8??, then 19. Nxh7# follows.
<19. Kxe2 Qe8+ 20. Kf2 Nf6 21. Rhe1 Ne4+> If 21...Qd7, then White mates after 22. Re7 Bd5 23. Nxh7+ Kg8 24. Nxf6+ Bxf6 25. Qxd5+ Kh8 26. Qxa8+ Qe8 27.
Qxe8#.
<22. Rxe4> 1-0
Black resigns in lieu of 22...Bxe4 23. Nxh7#. |
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sac: 15.Bxf7+