|
< Earlier Kibitzing · PAGE 3 OF 3 ·
Later Kibitzing> |
Apr-09-09
 | | johnlspouge: Thursday (Medium):
G Szabo vs S Zawadzki, 2004 (27.?) White to play and win.
Material: R for N+2P. The Black Kh8 has 2 legal moves, both light squares. The White Bb3 on the a2-g8 attacks g8 indirectly, as does Qg3. The White Rf1 and Rg1 both have semi-open files and can remove K-side defenders Ne5 and Bf6. The White Kg1 is open on the b8-g1 diagonal to …Qb6+, which with …Qd4 in some variations is irrelevant in the following. White’s primary objective is to activate the heavy pieces, particularly Qg3, against the Black Kh8, probably with exchange sacrifices. Candidates (27.): Rxe5, Rxf6, Bxf7
27.Rxe5
To maintain material equality, Black must recapture:
(1) 27…dxe5
(28.Bxf7 Bf5 looks difficult to crack.)
<[The move I went for instead was 28.Rxf6, in which best play gives some pull to Black, as follows:28.Rxf6 exf6 29.Bxf7 g5
I missed the game continuation ending with 29.Rxf5 gxf5 30.Bg7+. At 15 plies, Toga says 27…dxe5 was indeed Black’s best defense, but I thought 27…Bxe5 the more troublesome defense to a human.]> (2) 27…Bxe5
<[Here, I went for
28.Qh4 Be6 29.Bxe6 fxe6 30.Be3+, etc.
which Toga evaluates at about +1 P for White. I rather overlooked the following mate-in-5, however: 28.Bg7+ Bxg7 [Kxg7 29.Rxf7+ etc.]
29.Qh4+ Kg8 30.Bxf7+ Kf8 31.Be6+ Bf6 32.Qh6#]> |
|
Apr-09-09
| | johnlspouge: Even without the clue that the position is a puzzle, the exchange sacrifices merit consideration, because the Rs are not as active against the Kh8 as the Bs. The choice between the candidates I listed was not immediately obvious to me, so I calculated a few other variations, but focused quickly on 27.Rxe5, because it eliminated Ne5, permitting the P shield around Kh8 to be stripped away, i.e., I settled on an attack penetrating first on the light squares. |
|
| Apr-09-09 | | beenthere240: It's curious how thematic the bg7+ sacrifice is in many variations, since it opens the h file with check. Without that, black gets a critical extra tempo for defense. |
|
| Apr-09-09 | | JG27Pyth: Great write up Once!
My kid's are home from school for spring vacation... the chess concentration suffers... |
|
| Apr-09-09 | | penguin496: I thought the theme for the week was leaving greek gifts? |
|
| Apr-09-09 | | CHESSTTCAMPS: White has an exchange for two pawns and his pieces are actively deployed for a king-side attack, whereas black's Q, R and Bd7 are not placed to defend the king well. White clearly has a big advantage. The general plan of attack for white must be to knock out (or divert) one or both of the most active king-side defenders (the Bf6 and the Ne5) and infiltrate with the queen. Therefore, reasonable candidates for white are Rxe5, Rxf6, or Bg5. Choosing the right move must be based on accurate
analysis. My first thought on seeing the position was Rxe5, to exploit black's obvious weakness at the traditional weak square, f7. So we'll examine the most logical candidate first and see how it plays out: 27.Rxe5
There are only two reasonable possibilities here:
A. 27...dxe5 (ugh) 28.Bxf7 Bf5 29.Rxf5! (look at checks and captures first) gxf5 30.Qg6 Rg8 (30....Rf8 31.Bg7+! Bxg7 32.Qh5+) 31.Qh5 Rg7 32.Bxg7+ Kxg7 33.Qg6+ Kh8 (Kf8 34.Qg8#) 34.Qh6#. This line shows that the passive rook on e8 has little defensive value. Black can insert Qb6+ in these lines, but after Kh2, the queen has no path to join the K-side defense in time. A.1 28....Rg8 29.Rxf6! exf6 30.Qh4 and the threat of Bf8# is deadly e.g. 30...Rg7 31.Bg5+ Rh7 32.Bxf6+ Qxf6 33.Qxf6+ wins B. 27...Be5 28.Qh4 Be6 29.Bxe6 fxe6 30.Bf4+ Kg8 (Kg7 31.Qh6+) 31.Bxe5 dxf5 32.Qh6 Rf8 (else Qxg6+ followed by Rf7) 33.Qxg6+ Kh8 34.Qxh6+ Kg8 35.Rxf8+ Qxf8 36.Qxf8+ and white's connected passed pawns tie up the black king and win the ending - black's tripled e-pawns will all be captured. B.1 28...Bf6 29.Bg5+ Kg7 (Kg8 30.Rxf6 exf6 31.Bxf6 wins) 30.Qh6+ Kg8 31.Qxg6+ wins B.2 28...Kg8 29.Bxf7+ and mate next move
B.3 28...e6 29.Bg5+ wins
I think that's it - no need to examine the other candidates. |
|
Apr-09-09
 | | Domdaniel: <beenthere240> -- <It's curious how thematic the bg7+ sacrifice is> Yes -- this is a crucial point. The same idea, in slightly different form, turns up in the main subvariation after 27.Rxe5 Bxe5 28.Bg7+! and again in the game continuation after 29.Rxf5 gxf5 30.Bg7+! -- with forced mate in both cases. |
|
| Apr-09-09 | | mworld: darn, i saw the idea of this line, but I couldn't see the rather lengthy forced mate that would happen if black retook the rook with Bxe5 which I think is the real trick to understanding this puzzle. Taking out g6's defender jumps right out of the starting position. |
|
Apr-09-09
 | | kevin86: A neat problem-the first exchange sac was easy---the second was somewhat harder. Each had a similar purpose:to eliminate black's key defender at the time. |
|
Apr-09-09
 | | Jimfromprovidence: In the continuation 27 Rxe5 dxe5 28 Bxf7 Rg8 I preferred the subtler 29 Rd1 below over 29 Rxf6.
click for larger viewNow, black’s bishop is both en prise and pinned. The black queen also has to stay close to guard the bishop. A likely continuation is 29…Qb6+ 30 Be3 (not Kh1) Qc6 31 Bxg8 Kxg8 32 Qxg6+.
click for larger viewWhite is up an exchange along with a very strong attacking position. |
|
| Apr-09-09 | | vaskokibika: OTB I would play my move: 27.Bxf7
And then for example 27...Nxf7 28.Qxg6 Nxh6 29.Qxh6+ Kg8 30.Qg6+ Kf8 31.Re4
click for larger view |
|
| Apr-09-09 | | beenthere240: 22. I was wondering about 22. Rad1 (the rook moves obviously to avoid the black bishop, but why to d1 and not to e1? The r moves to e1 3 moves later anyway. |
|
| Apr-09-09 | | TheChessGuy: Black's position is just so passive. The trick is to figure out how to rip it open. |
|
| Apr-09-09 | | YouRang: Oy, another bad week for me. :-(
I looked at 27.Rxe5, but didn't see a good reply to 27...Bxe5. All I saw was 28.Qh4 Be6, with various and sundry dead-ends to follow. Now (with the computer's help), I see that I had an almost shocking mate-in-4 with 28.Bg7+! Then: 28...Bxg7 29.Qa4+ Kg8 30.Bxf7+ Kf8 31.Be6+ Bf6 32.Qh8#. Or: 28...Kxg7 29.Rxf7+ with the queen mating at h7 next. |
|
| Apr-09-09 | | sshhhh: A variation on <DoubleCheck>'s 28...Rg8 line: 27. Rxe5 dxe5
28. Bxf7 Rg8
29. Rxf6 exf6
30. Qh4 g5
31. Qh5 Rg7
Where's the win here? (A) 32. Bxg5+ Rh7 33. Bxf6+ (as in DoubleCheck's line) Qxf6. Or (B) 32. Bxg7+ Kxg7 33. Qg6+ Kf8 34. Qg8+ Ke7, and I can't find a win. Seems to me there must be something here. What am I missing? |
|
Apr-09-09
 | | Once: <DoubleCheck: I hope <Once> that answers your question of Why Black cant play 27...Bxe5?> I think we have established that 27...Bxe5 doesn't save Black. But it needs careful analysis to be sure. Let's have a look at one possible line (courtesy of Herr Fritz) 27...Bxe5 28. Qh4?! (Bg7+) Be6 29. Bxe6 (what else?) fe 
click for larger viewFritzie reckons that white has an advantage of +2, and it's fairly easy to see why. But there is no immediate mate in prospect. The queen and bishop duo may look scary, but I'm not exactly sure what they are going to do... My point is that none of this is immediately obvious from the starting position. The position needs to be unpeeled bit by bit and line by line. So before I play 27. Rxe5 OTB I would would want to check that black doesn't have a sneaky defence like 27...Bxe5 and 28...Be6. A non forcing move like 28. Qh4 might fizzle out if white cannot bring more attackers to the party. The bottom line is that I have learnt from long and bitter experience that real world chess and Thursday CG problems are very rarely as "clearly obvious" as your very first post suggested. Our enjoyable and instructive work (with help from Herr Fritz) has shown that Black cannot save himself after 27. Rxe5, But I am not a good enough analyst to be sure of this OTB without wading through the lines in some detail first. |
|
Apr-09-09
 | | agb2002: White has the exchange for a knight and two pawns and an overwhelming attack against the black king. The most important black piece is the knight. Therefore, 27.Rxe5: A) 27... Bxe5 28.Qh4 (threatening 29.Bg7+ Kxg7 30.Rxf7+ Kg8 31.Qh7#) A.1) 28... g5 29.Bg7+ Kxg7 30.Rxf7+ Kg6(8) 31.Qh7#.
A.2) 28... e6 29.Bg5+ + -.
A.3) 28... d5 29.Bf4+ and 30.Bxe5 + -.
A.4) 28... Be6 29.Bxe6 fxe6 30.Bg5+
A.4.a) 30... Kg7 31.Qh6+ Kg8 32.Qxg6+ Kh8 (32... Bg7 33.Bh6 Qb6+ 34.Kh1 Qd4 35.Qxe8+) 33.Rf7 + -. A.4.b) 30... Kg8 31.Qh6 Bf6 32.Qxg6+ Kh8 (32... Kf8 33.Bh6+) 33.Rxf6 + -. A.5) 28... Bf6 29.Rxf6 exf6 30.Bg5+ Kg7 (30... Kg8 31.Bxf6) 31.Qh6+ Kg8 32.Qxg6+ Kh8 (32... Kf8 33.Qxf7#) 33.Bxf6+ + -. A.6) 28... Bf5 29.Bxf7 Bf6 30.Bg5+ Kg7 31.Bxe8 Qxe8 32.Bxf6+ exf6 33.Qxb4 + -. A.7) 28... Qb6+ 29.Be3+ + -.
A.8) 28... Kg8 29.Bxf7+ Kh7(8) 30.Bf8#.
B) 27... dxe5 28.Bxf7 (threatening 29.Qxg6, 28.Rxf6 looks weaker: 28... exf6 29.Bxf7 (29.Qh4 Kg8) Rg8 30.Qh4 g5 31.Qh5 Rg7 32.Bxg7+ Kxg7 33.Qg6+ Kf8) B.1) 28... Rg8 29.Bxg8 Qxg8 30.Bg5 + -.
B.2) 28... Bf5 29.Rxf5 (29.Bxe8 is not so strong) gxf5 30.Bg7+ Bxg7 (30... Kh7 31.Qg6#) 31.Qh4+ Bh6 32.Qxh6#. B.3) 28... Qb6+ 29.Kh2 Bg7 30.Qh4 g5 31.Bxg5+ Bh6 32.Bxh6 + -. C) 27... Qb6+ 28.Be3 + -.
Time to post, check and have dinner. |
|
| Apr-09-09 | | SpoiltVictorianChild: Saw the first two moves, didn't think about ...Bf5, but figured the line would win at least a couple pawns. I don't know if I would have seen Bg7+ otb. |
|
| Apr-09-09 | | WhiteRook48: missed it. Thinking 27. Rxf6 instead, thinking of seizing g7 somehow |
|
| Apr-09-09 | | CHESSTTCAMPS: <Once:> wrote <[snip]27...Bxe5 28. Qh4?! (Bg7+) Be6 29. Bxe6 (what else?) fe ... But there is no immediate mate in prospect. The queen and bishop duo may look scary, but I'm not exactly sure what they are going to do...> Having missed the sharper, quicker 28.Bg7+!! line, from your diagrammed position, I went for a forced sequence leading to a won king and pawn ending with 30.Bf4+ Kg8 (Kg7 31.Qh6+) 31.Bxe5 dxf5 32.Qh6 Rf8 (else Qxg6+ followed by Rf7) 33.Qxg6+ Kh8 34.Qxh6+ Kg8 35.Rxf8+ Qxf8 36.Qxf8+ Not the best, but it works. |
|
| Apr-09-09 | | patzer2: For today's Thursday puzzle, the exchange sacrifice 27. Rxe5! decisively undermines Black's helpless King position. |
|
Apr-09-09
 | | OhioChessFan: I must be a crazy Rook move expert. Very easy week so far. |
|
| Apr-09-09 | | muralman: I had this one figured out to the end on first thought. I got Monday's with the help of my sharp son urging me on. Tuesday, and Wednesday were busts. Just like always, when the puzzles get tougher, the gamer has a better chance seeking the key. With no knowledge of chess tactics; sequential logic, and imagination, fills the need nicely. I am in awe of the fellows here who can read and write chess like it was their primary language. |
|
Apr-10-09
 | | al wazir: I see that I miswrote my moves earlier, as usual. My solution was 27. Rxe5 dxe5 28. Rxf6!? exf6 29. Bxf7. If 29...Rg8, then 30. Qh4. Now if 30...Rg7, 31. Bg5+ Rh7 32. Bxf6+ wins. |
|
Apr-10-09
| | Domdaniel: <muralman> -- <I am in awe of the fellows here who can read and write chess like it was their primary language.> Nicely put. The similarities between chess and language -- along with some crucial differences -- have obsessed me for years. It started 30-odd years ago, as a teenager. I'd started to play relatively late, aged 15 or 16. Despite the fact that my rating shot up to 2000 in 3 quick spurts -- 1650, 1850, 1980, and voila -- I could already see that, for example, I had almost zero chance of title norms, wins in strong tournaments, making a national team, etc. There were at least 4 or 5 other teens who were stronger, whose ratings stayed ahead of mine, and who tended to beat me more often than not. And the common factor is that they'd all begun playing at an earlier age. Maybe this is an excuse: a story I've been telling myself for 30 years to explain away failure. But even then I suspected, dimly, that chess was like language -- and fluency is achieved if you start young enough. Start late and you'll always have an accent. My chess accent must be pretty horrendous to a GM. I've gradually picked up a basic vocabulary: but I still have to *think* about it, to mentally translate into English, to get idioms wrong ... OK - the analogy breaks down in places. But the central idea -- that brains are wired for language acquisition at an early age (the feat of the average child's brain in picking up Arabic or Danish or Guarani or Ijo is truly incredible). A few other human activities (chess, music, math -- the ones where you find child prodigies -- and which have formal structures, combinatorial depth, but little need for extensive life experience) are able to piggyback on (a part of) the language acquisition machinery. Ijo, btw, is an African language with a very rare feature: it uses some implosive sounds, made by sucking in air rather than expelling it. The chess equivalent? I've no idea ... maybe some endgame maneuver that is rare, beautiful and downright weird ...? But there's no need for awe. I don't believe that chess is anyone's *first* language -- maybe somebody like Sultan Khan came closest. So everyone has a chess accent, however slight. Meanwhile, my chess 'fluency' seems to have improved -- I find better combinations, and I 'understand' the openings I play without having to memorize long lines. But I blunder more too, so results are worse and my rating has dropped. Is there any linguistic equivalent of this, I wonder? I made a hilariously horrible - and totally unprintable - language blunder once (aka a faux pas?) while trying to speak French. At least chess blunders aren't met with torrents of laughter from everyone in the room. Not yet, anyhow. Maybe I need to find better (or worser) blunders. |
|
 |
|
|
< Earlier Kibitzing · PAGE 3 OF 3 ·
Later Kibitzing> |
Kibitzing
sac: 27.Rxe5