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Jul-12-05
 | | benveniste: I spent about 15 seconds finding the R-sac/N-fork combo, and about 10 minutes trying to figure out how it wins. I eventually shrugged and said, "that's why I can't play this game" and peeked. While White gains material, if Black can avoid creating a queen-side passed pawn for white, I think there are good chances for a draw. Even after 30 ... a5?, the win took almost perfect play. |
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| Jul-12-05 | | paul dorion: Lasker did sacrifice his Q for R-B-P in his Moscow 1925 game against Ilyin-Zhenevsky and won. The key for the correctness of the sacrifice is the solidity of the pawn structure. It is well known that if the side with the pieces has a solid structure , he even have winning chances. |
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| Jul-12-05 | | patzer2: I ran today's puzzle position (27. ?) on my PC for four hours at 2.0 GHZ to 18/51 depth and 1201 kN/s with the following results (note that it rates 27. Ng5+ equal to 27. Rf7+): Spraggett Kevin (CAN) - Jonathan Berry
2b1rb2/2rnq2k/pp1p2p1/3Pp3/PP2N1p1/5R2/2P2PB1/2BQR1K1 w - - 0 1 Analysis by Fritz 8:
1. ± (1.38): 27.Ng5+ Kg8 28.Rf7 Qxf7 29.Nxf7 Kxf7 30.Qxg4 Nf6 31.Qe2 a5 32.Bg5 axb4 33.Qb5 Bf5 34.Qxb6 2. ± (1.38): 27.Rf7+ Qxf7 28.Ng5+ Kg7 29.Nxf7 Kxf7 30.Qxg4 Nf6 31.Qe2 a5 32.Bg5 axb4 33.Qb5 Bf5 34.Qxb6 3. ± (1.19): 27.Bg5 gxf3 28.Bxe7 Bxe7 29.Qxf3 Kg7 30.Qe3 Bb7 31.Ng5 Bxg5 32.Qxg5 Nf6 33.Qe3 Nxd5 4.  (0.34): 27.Rg3 Nf6 28.Bg5 Bg7 29.f3 Rf8 30.fxg4 Qd7 31.Qd2 Nxe4 32.Bxe4 Kg8 33.Bxg6 Qxa4 34.Be4
5. = (0.25): 27.Ra3 Nf6 28.Bg5 Bg7 29.Qe2 Rf8 30.c4 Rb7 31.Rg3 Qc7 32.Bxf6 Bxf6 33.c5 6. = (0.16): 27.Rb3 Nf6 28.Qd3 Nxe4 29.Bxe4 Qf7 30.Be3 b5 31.axb5 axb5 32.Qxb5 Bf5 33.Bb6 Rb7 34.c4 Bxe4 7. = (-0.22): 27.Rd3 Nf6 28.Bg5 Bg7 29.Rg3 Rf8 30.f4 gxf3 31.Bxf3 Qe8 |
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Jul-12-05
| | beenthere240: I agree. The puzzle is just to find the deflection into the knight forkl. But a much deeper problem is how to proceed. Grabbing the g pawn is a bad idea, but switching to an attack on the q side is right. |
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| Jul-12-05 | | paul dorion: <Patzer2> Nice work , but I still prefer Spraggett 30 Be3. The g4 pawn will go nowhere (and is a doubled pawn) and is an hindrance to black pieces. Curious that Fritz also gives a line with a passed pawn for White after black rushes to play a5. It is clear that the bishop would do more to support the pawn by being on e3 rather than on the useless g5. |
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| Jul-12-05 | | patzer2: <beenthere240> My personal preference might have been to avoid "grabbing the g pawn" with 30. Qxg4 and instead play 30. Be3 as in the game. However, I don't think it's a mistake, and, as Fritz 8's choice, may indeed be the best move here. White appears to have a won position after 30. Qxg4!? Nf6 31. Qe2! a5 32. Be3 axb4 33. Bxb6 Rc3 34. Qb5 Rxc2 35. Qxb4 Ba6 36. Bf1 Bxf1 37. Kxf1!  ( 1.44 @ 14/45 depth & 1133kN/s). |
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| Jul-12-05 | | YouRang: This one was fairly easy. Again, when a knight is within checking range of a king, you look for ways to force a knight fork. The setup move, Rf7+, then jumps into view. |
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| Jul-12-05 | | notyetagm: The Black queen is the only defender of the f7-square, stopping the royal rook fork ♖f3-f7+. The Black queen is also the only defender of the g5-square, stopping the White e4-knight from checking the Black king. Unfortunately for Black, <the squares f7 and g5 are a knight's move apart from each other>, meaning that the Black queen can defend only one. 27 ♖f7+! <deflects> the Black queen from defending the g5-forking square and simultaneously <decoys> her on to the f7-square, where she becomes the second target for the knight fork 28 ♘g5+, winning queen for rook and knight. 27 ♖f7+!, a very nice <decoy/deflection into a knight fork>. |
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| Jul-12-05 | | aginis: i'm glad to have initiated such heated discussion and i think that <thebeginner> is definetly onto something with 31.Qd3 followed by 32.Be4 ironically in his own analysis he suggests <30 ..b5
31 axb5 ..axb5
32 Bf1 ..Rb7
33 Qxg4 ..Nf6 >
while 32.Qd3 will again serve admirably.
<patzer2> i tend to distrust computer analysis of subtle positions like this.
the computer must use an algorithim to rate positions (to see each position for 15 half moves is approximately 10^20 positions; at a rate of a billion positions per second thats a thousand years)
in a position were 4 or 5 moves down the road it needs to decide which pawn to win it will favor taking a pawn immediately over taking one a few moves later because it will never even analyse the reprecussions of 30.Be3. however i'm curious what evaluations fritz will give after 29...Kxf7, 30.Be3 and 30.Qxg4 |
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| Jul-12-05 | | ajile: I thought that the move was NG5+ first since next move White invades the 7th with RF7. This looks extremely dangerous for Black. After 27.NG5+ KG8 28.RF7 QD8 29. QXg4 NF6 30. QH4 threatens RXN. I don't have my chess set handy so hard to see what happens after 30...RE7. |
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| Jul-12-05 | | The beginner: <Aiginis>
White can play 32 Qd3 or Bf1 it makes not much diference in the .. 30b5 line(Actually Bf1 is better because it threatens pawn on b5, while the queen is still threatening pawn on g4).
The point here is to threaten b5. In this line white cant follow up Qd3 with Be4 with the same idea as in the 31 Rb7 line i gave above, because black can play Nf6 covering the e4 square. 30 ..b5
31 axb5 ..axb5
32 Qd3 ..Nf6
33 Be4? ..Nxe4
34 Qxe4 ..Bf5
35 Qh1, or Qg2 (forced) ..Bg7
Here black has at least a draw, or more likely winning chances. Material is equal, black has the tempo, bishop has target pawn on c2. White's pieces are pointing no where, and his pawn on c2 is soon to go off the board, he has no connected pawns, the queen has no good squares to move to. |
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| Jul-12-05 | | paul dorion: <ajile> after 29 Qd3 look better than Qxg4 and after the forced 29 ...e4 30 Rxe4 black loses material fast to stop Qxg6+ Anyway Ng5+ and Rf7 are not really an independant branch because black can play Qxf7 transposing into the game. |
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| Jul-12-05 | | paul dorion: <The beginner> after 30 Be3 b5
31 axb5 axb5
32 Qd3 Nf6
33 Qxb5 Rxc2
34 Ra1 white will have a nice position.
Forget about K side attack by White , getting a passed pawn on the qside and opening up the position for the queen and rook will win the game. |
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| Jul-12-05 | | The beginner: <Paul dorion>
Yes you are right, my analys was only to point out why the idea Qd3 Be4 wont work in this variation. As it would have done, if black had played the variation i gave above why 30.. Rb7 followed by Nb8 is really bad. We where seeking for a better move than 30..a5, not sure if b5 is better, proberly not. The whole point of the discusion was that the puzzle seems a bit hard for thuesday, as if there is a win for white it is many moves ahead. Capturing the queen for R,N and pawn is not really a win. Unless the one who solve the puzzle can see a clear win i would not call it to solve the puzzle. |
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| Jul-12-05 | | paul dorion: <the beginner> A plan would be 30...Rc4 followed by Bb7 and possibly Rec8. If white can be forced to play c4 then it may have to sacrifice a pawn on the queenside to break trough, On b7 and d7 , the B and N are protecting some valuable squares. With a closed position , the W queen may be difficult to activate. I think that white is on top but still have to win the game. You are right that this puzzle is wrong, the superior side should always emerge with a clear win at the end of solution. |
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| Jul-12-05 | | paul dorion: Black should avoid at all cost letting white get a passed pawn and simplify. |
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| Jul-12-05 | | The beginner: <Paul Dorion>
I dont think Rc4 leads anywhere for black eather, as black will never get time to play Bb7 nor Rec8, if white goes on with the idea Qd3 Be4. 30.. Rc4
31 Qd3 ..Rxb4
32 Be4
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| Jul-12-05 | | sharpnova: <jahhaj> you're actually quite wrong. all it does is give black an extra possibility which fairs him WORSE. he may ignore it if he wishes in which case it is equal to the text move. if he doesn't, he falls into a deeper pitfall.. so it is better to play Ng5+ |
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| Jul-12-05 | | aginis: <the beginner> i was just pointing out that if 30...b5 31.axb5 axb5 32.Qd3 and either Qxb5 or Be4 follows black can not protect against both. |
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| Jul-12-05 | | YouRang: Would 42. Qb8 be stronger than the text (Qxc7)? How would black respond? |
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| Jul-12-05 | | aw1988: Probably even easier than Monday. |
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| Jul-12-05 | | patzer2: <aginis> <I'm curious what evaluations Fritz will give after 29...Kxf7, 30.Be3 and 30.Qxg4> Although I think Fritz 8 is under estimating White's chances with 30. Be3, here's its analysis (30. ?) @ 18/51 depth & 1179kN/s: Spraggett Kevin (CAN) - Jonathan Berry
2b1rb2/2rn1k2/pp1p2p1/3Pp3/PP4p1/8/2P2PB1/2BQR1K1 w - - 0 1 Analysis by Fritz 8:
1. (1.44): 30.Qxg4 Nf6 31.Qe2 a5 32.Qb5 axb4 33.Qxb4 Ra7 34.f4 Bf5 35.Bb2 Nd7 36.Be4 Rea8 2. ± (1.03): 30.Be3 b5 31.axb5 axb5 32.Qd3 Nf6 33.Qxb5 Rxc2 34.Rc1 Rxc1+ 35.Bxc1 Bf5 36.Be3 Be7 37.Qb7 Nd7 3. ± (1.03): 30.Qe2 Nf6 31.Be3 b5 32.axb5 axb5 33.Qxb5 Rxc2 34.Rc1 Rxc1+ 35.Bxc1 Bf5 36.Be3 Be7 37.Qb7 Nd7 4. ± (0.94): 30.Bg5 Nf6 31.Qd3 Be7 32.Rc1 b5 33.axb5 Bf5 34.Qf1 axb5 35.Qxb5 Rc3 36.Bxf6 5. ± (0.94): 30.Qd3 Nf6 31.Bg5 Be7 32.Rc1 b5 33.axb5 Bf5 34.Qf1 axb5 35.Qxb5 Rc3 36.Bxf6 6. ± (0.88): 30.Bf1 Bg7 31.Qxg4 Nf6 32.Qg5 Bf5 33.c4 Rh8 34.Qg3 Nd7 35.Bg5 Bf6 36.Be3 Be4 7. ± (0.78): 30.f4 gxf3 31.Qxf3+ Nf6 32.Bg5 Be7 33.Qf2 b5 34.axb5 axb5 35.Be4 Rc4 36.Bxf6 Bxf6 |
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| Jul-12-05 | | jmuller: Fork and fork!
Who needs knives or spoons? <g> :-) |
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| Jul-12-05 | | alexandrovm: 27. Rf7, and black loses his queen. If Qxf7, comes 28. Ng8+, with a fork, wining the queen for a rook and a knight. |
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| Mar-04-15 | | kevin86: Queen me! |
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Kibitzing
sac: 27.Rf7+