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|Dec-01-10|| ||stacase: Pinned pieces and discovered checks are always fun (-:|
|Dec-01-10|| ||CHESSTTCAMPS: White is down a pawn, but the semi-open f and g-files are completely dominated by white's majors, yielding a winning attack. The focus of the white battering ram is the f6 pawn, so the primary candidate is obvious:|
27.Rxf6 threatens 28.Rxf8+ (forcing mate) and Rxb6, leaving no satisfactory defense:
A) 27... gxf6 28.Bxf6+ Bg7 29.Rxg7 (Bxg7+ Kg8 30.Bd4+ also wins) Rf8 30.Rh7+! Kxh7 (Kg8 31.Qg3+) 31.Qf5+ forces mate.
A.1) 29... h6 (otherwise 30.Rg6+ Qxf6 31.Qxf6#) 30.Re7+ Kg8 31.Qg3+ forces mate.
B) 27... Kg8 28.Rxf8+ Rxf8 29.Rxg7+ Kh8 30.Qxf8#
C) 27... Qxe3 (best) 28.Rxf8+ Rxf8 29.Qxe3 Rxe3 30.Bxg7+ Kg8 31.Bh6+ Kf7 32.Bxe3 and black is down a bishop in a resignable position.
|Dec-01-10|| ||CHESSTTCAMPS: <agb2002: The game continuation is much better than my line D. Simplification does not always simplify the game...> So true - I did the same in my line C. In chess, we often need to embrace complexity to find the best play.|
|Dec-01-10|| ||johnlspouge: < <Once> wrote: [snip] In today's puzzle, the "obvious" tactic works. But can we really decide that without calculating variations? In a blitz game probably, but with classical time controls you do run the risk that the other guy will find a saving resource - a perpetual or a counter-sac. [snip] >|
I am with <Once>. Usually, a sacrifice achieves a strategic objective that no other move accomplishes (here, busting the Black castle). If refusal is vanilla, only acceptance requires calculation (because the gain of material often triggers Kotov's rule: "Calculation ceases with the win of a P without complications"). Here, 27...Qxe3 introduces novel defensive resources, which a priori might lead to unexpected complications. Personally, I calculated the consequences of 27...Qxe3 before concluding a win for White.
After all, as only <agb2002> and <M.Hassan> point out, White is a P down, so Black's defensive resources include the counter-sacrifice of a P. Because of these types of resources, I always start an analysis with a material count, preliminary to the extraction of positional features and then the hard analysis.
Oh, yes, and this is not the first time I have used "a priori" in a sentence ;>)
|Dec-01-10|| ||johnlspouge: < <CHESSTTCAMPS> wrote: White is down a pawn [snip] >|
Such good habits :)
|Dec-01-10|| ||Patriot: <Dr. J>
<For this purpose one only needs to confirm that Black cannot recapture after 27 Rxf6. Other Black tries must necessarily fail and do not really need to be analyzed.> I agree that 27.Rxf6 is strongly suggested and this is a good reason to at least consider this move but not good enough to stop there IMO. For example, on 27...Qb8 is white only equalizing in material? If so maybe there is something better like 27.Bxf6. Or after 27...Qxe3, is black still ahead materially? I think that 27...Qxe3 is the best attempt to maintain a material edge while stopping a back-rank mate.
<Consider this: the "point" of 27 ... Qxe3 is to exchange the White queen, but this does not succeed. After all, why should it? It is not the queen that is actually the real threat to Black's king.> The queen IS a threat. After 27.Rxf6, white is threatening 28.Rxf8+ Rxf8 29.Qxf8#.
<Likewise, after 27 ... Qb8 the crossfire means that one just knows even without calculation that the win must be there, and indeed there are many ways to win this. (One unusual way is 28 Rxf8+ Qxf8 29 Rxg7.)> White has equalized materially, but I agree that white's position is very strong. With equal material, I would want to look a bit further. It doesn't take much to see that 28.Rxf8+ Qxf8 29.Bxg7+ Qxg7 30.Rxg7 Kxg7 31.Qg2+ wins the rook and maintains serious material.
It could be that you are more of an intuitive player than myself. I usually stop analyzing when one side wins significant material and the other has no moves that refute it. Some analyze further because they are using the puzzle as a way of improving board vision or it's also possible they don't know when to stop analyzing!
|Dec-01-10|| ||patzer2: For today's Wednesday puzzle solution Wainwright's 27. Rxf6! demolishes Blackburne's pawn structure and initiates a mating attack.|
The combination, also involves the deflection (removing the guard), double attack and discovered check tactical themes as part of White's mating attack. From the final position, it's mate-in-two.
|Dec-01-10|| ||Patriot: <johnlspouge> <After all, as only <agb2002> and <M.Hassan> point out, White is a P down, so Black's defensive resources include the counter-sacrifice of a P. Because of these types of resources, I always start an analysis with a material count, preliminary to the extraction of positional features and then the hard analysis.>|
That is very good practice. I rarely count material and I almost overlooked the ...Qxe3 defense. So looking at the opponent's threats is also good practice before delving into anything. I believe the main reason I don't usually count material is that most of these puzzles revolve around dynamics rather than material. Plus with the "very easy" Monday's and "easy" Tuesday's, there is usually a quick knockout punch somewhere. And by the time Wednesday rolls around, I have completely forgotten to check material first.
|Dec-01-10|| ||scormus: <Patriot> Its good practice to count the material first (or "a priori" if you like), but I confess I usually dont. On one occasion I "solved" a Sunday puzzle, winning the Q for an R. Unfortunately I proudly posted it before I realised I was a priori an R down.|
BTW, I've never used the term "a priori" before in any kibitz. As my granny might have said, "theres an a priori for everything"
|Dec-01-10|| ||kevin86: White manages to carry out a mate even with the queen pinned and doubly attacked.|
|Dec-01-10|| ||LIFE Master AJ: 27.RxP/f6! seems to win on the spot, only a couple of lines to calculate ...|
|Dec-01-10|| ||LIFE Master AJ: George Edward Wainwright - Joseph Henry Blackburne [D44]
Shrewsbury Shrewsbury, 1906
1.d4 d5 2.c4 e6 3.Nc3 dxc4 4.e3 Nf6 5.Nf3 a6 6.Bxc4 b5 7.Be2 Nbd7 8.0-0 Bb7 9.a3 Bd6 10.Qc2 Qe7 11.b4 e5 12.Bb2 e4 13.Nd2 0-0 14.Rae1 Rfe8 15.f3 exf3 16.Bxf3 Bxf3 17.gxf3 Nb6 18.Rf2 Qe6 19.Rg2 Bf8 20.Nce4 Nxe4 21.fxe4 f6 22.Rf1 Kh8 23.Rf5 Nc4 24.d5 Qb6 25.Nxc4 bxc4 26.Qf2 Rxe4;
click for larger view
27.Rxf6! Qxe3; Probably the best try.
[Bad was: 27...gxf6? 28.Bxf6+ Bg7 29.Bxg7+ Kg8 30.Bf6+ Rg4 31.Rxg4+ Kf7 32.Bh4+ Ke8 33.Rg8+ Kd7 34.Qf5+ Kd6 35.Qe6#;
Or 27...Qb8; 28.Rf7!,
(Or 28.Rxf8+ Qxf8 29.Bxg7+ Qxg7 30.Rxg7 Kxg7 31.Qg2+ Kf6 32.Qxe4 )
28...Rg4; 29.Rxg4 c3; 30.Bxc3 Qc8; 31.Rfxg7 Bxg7; 32.Rxg7 Qg8; 33.Rg3+ Qg7; 34.Bxg7+ Kg8; 35.Ba1#. ]
The game concluded:
28.Rxf8+! Rxf8 29.Bxg7+ Kg8 30.Be5+ , Black Resigns. [(Any square from a1 to e5 works.) I.e., 30.Ba1+, etc. ] 1-0
Analysis with Houdini, checked with Fritz 12.
|Dec-01-10|| ||Zozeke: This puzzle is like 'let's find the first move and briefly look through the variatons, because position is so good, you are going to win even if you miss something'. That being said, I went 27. Rxf6 without hesitation, and although Black's defensive response would probably puzzle me a little over-the-board, I think I can award myself a Wednesday cookie.|
|Dec-01-10|| ||BOSTER: <dzechiel> 27.Rxf6 <is there anyone here who didn't see that move instantly? I don't see any hands>.
Now I can see <dzechiel> improved his tactical vision,but ,nevertheless , has problem with calculations,because he didn't count my hand.|
|Dec-01-10|| ||Patriot: <BOSTER> I'm betting you went with 27.Bxf6?|
|Dec-01-10|| ||niemzo: mastermind7994 is right. Actually, many games in this same line are listed with the d44 eco code, which is rather confusing.|
|Dec-01-10|| ||Dionysius: <Once> Love your story. Probably should end "...but 0-1 all the same". :-)|
|Dec-01-10|| ||BOSTER: <ruzon> <Now if <CG> could just explain how to get ... into puzzle situation, I'd be all set >.
You can read the game and understand himself. But I'd like to show you how at least try to win for black after 15.f3.
Of course I have opposite opinion than <Once>. This is position after 15.f3.
click for larger view
White position is very cramped,most pieces on the Queen's side,and black squares h2,g3 and e3 are weak (after15.f3).
So I'd sacr.the Knigt to open the road for Black Queen 15...Ng4. White have to accept, because the threats Nxe3 and Bxh2. 16.fxg4 Qh4.
And now we have the diagram after 16...Qh4 with White to play. Even Black has only three active pieces-Q,R and B white position is very difficult to protect.
click for larger view
|Dec-01-10|| ||messachess: This is unbelievably easy.--hardly a puzzle at all.|
|Dec-01-10|| ||WhiteRook48: 27. Rxf6.If 27...Qxf6?? then 28 Bxf6. if 27...gxf6, then 28 Bxf6+ Bg7 (28...Qxf6??? 29 Qxf6+ is mate in two) 29 Bxg7+ Kg8 30 Bd4+. Declining leads to Rxf8+ followed by Bxg7+|
|Dec-01-10|| ||Brandon plays: The first move is really easy to see, but then you start seeing counterplay chances for black. However, I think I have calculated out a variation that works for white. Rxf6 Qxd3 Rxf8 Rxf8 Qxd3 Rxd3 Bxg7 Kg8 Bh6! etc...|
|Dec-01-10|| ||Brandon plays: Ehh, I missed the checkmate idea for white. My idea worked, however, but it definitely wasn't as good of a finish.|
|Dec-01-10|| ||wals: Rybka 4 x 64
depth: 20 : 4 min :
( 0.28):10...Qe7. Best, c5, -0.29.
depth: 18 : 5 min :
(-0.60):20.Nce4. Best, e4, -0.11.
depth: 22 : 20 min :
(=0.00):20...Nxe4. Best, Nfd5, -0.79.
1. (-0.79): 20...Nfd5 21.Bc1 f5 22.Nc5 Nxe3 23.Qd3 Bxc5 24.dxc5 Rad8 25.Qc3 Qf7 26.Rxe3 Nd5 27.Rxe8+ Rxe8 28.Qc2 Nf4 29.Qd1 Nxg2 30.Kxg2 Qd7 31.Qf1 Qd5 32.h4 Re5 33.Nb1 Qd4 34.Kg3 Re6
2. (-0.37): 20...Nbd5 21.Nxf6+ Qxf6 22.e4 g6 23.e5 Qe6 24.Nb3 Bh6 25.Nc5 Qe7 26.Qe4 c6 27.Nb3 f6 28.Nc5 Bg5 29.Kh1 Kh8 30.Rc2 f5 31.Qd3
depth: 19 : 4 min :
(=0.17):23.Rf5. Best, Qxc7, 0.48.
depth: 19 : 4 min :
(+0.80):23...Nc4. Best, Rad8, =0.00.
depth: 19 : 11 min:
(+7.86):24...Qb6. Best, Nxe3, +0.55.
depth: 18 : 4 min :
(+11.65):26...Rxe4. Best, Be7, +7.67.
completely outclassed Black resigned move 30.
|Dec-01-10|| ||Patriot: <BOSTER> Your line looks interesting. In the second diagram, how about 17.g3?|
17...Bxg3 18.hxg3 Qxg3+ 19.Kh1. If 19...Re6, 20.Rf5 (20...Rh6+ 21.Rh5) Nf6 21.Qd1.
Unless I'm just missing something, this could be drawish. I could be dead wrong so I'll take a look at this with Fritz.
|Dec-01-10|| ||Patriot: <BOSTER> I did miss something--a hanging rook! The line I mentioned is a draw. But black has 20...Rh6+ 21.Rh5 Rxh5+ 22.gxh5 Qxe1+ . White has 17.h3. 17...Qg3 18.Ndxe4 Qxe3+ 19.Kh1 Bxe4 20.Nxe4 Qxe4 21.Qxe4 Rxe4 22.Bf3 and white has a slight advantage. That is the principle variation according to Fritz. Not easy at all!|
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