|Sep-11-05|| ||dac1990: Wow, a game from 1972 that wasn't Fischer-Spassky. You don't see that too often.|
|Sep-11-05|| ||kevin86: A bizarre finish-both players have pawns on the seventh;but while black threatens to queen,white cannot carry out his similar threat due to black's checking chances:42 f8=♕ ♕xf8 43 ♖xf8 d1+ 44 ♘g1 and white is hopelessly entombed.|
Black's threat is 42...d1=♕ 43 f8=♕ ♕xf8 44 ♖xd1 and black wins!
|Sep-11-05|| ||patzer2: Boey's positional sacrifice 15...Ng3!? creates an interesting and difficult struggle after Estrin accepts it. Following 16. hxg3 fxg3 17. Qd3, Boey's 17...Bf5! forces Estrin into an unfavorable exchange of the Queen for three pieces. |
Such an exchange is often favorable to the side with more pieces, but in this case Boey is able to maintain a small but persistent advantage in this imbalanced position. Boey skillfully converts his small advantage of an extra pawn, queenside pawn majority majority and potential passed pawn to a decisive advantage.
Instead of accepting the sacrifice offer, I wonder if White might have done better declining it with 16. Rf2 = to .
After accepting the sacrifice, the alternative 22. Nxd4!? Qxd4+ 23. Kh1 Qxe5 24. Rb1 c5 25. Bd2 (-0.59 @ 20/52 depth & 1189kN/s) favors Boey, but might have given Estrin slightly better drawing chances. However, at this level of GM correspondence play, I wouldn't be surprised if Boey were able to push even this small plus for a win.
|Sep-11-05|| ||patzer2: Wow! Boey's 24...g5!! finds the winning move in the position, setting up a deep passed pawn combination. Notice how Boey utilizes a temporary pin and a plan to sacrifice the exchange and trap the Bishop on h3 as key elements of this forcing sequence.|
|Sep-11-05|| ||al wazir: <patzer2: Boey's positional sacrifice 15...Ng3!? creates an interesting and difficult struggle>. I'm not sure that was really a sacrifice. After 22...Bxe5 black has a queen and three pawns for rook + bishop + knight. White had very few alternatives. In the game as played black can force white to give back the piece by playing 17...Qh4 18. Qxh7+ (18. Rd1 Qh2+ 19. Kf1 Qh1+ 20. Ke2 Qxg2+ 21. Ke3 Rxf3+ or 21. Ke1 Qf2#; or 18. Re1 Qh2+ 19. Kf1 Qh1+ 20. Ke2 Qxg2+ 21. Kd1 Qxf3+, with three passed pawns for the knight, one of them threatening to promote) 18...Qxh7 19. Bxh7+ Kxh7. If 16. Re1 black again has 16...Qh4. Then 17. Qd3 transposes into the line above, while after 17. Qd2 or Be3 there follows 17...Qh2+ Kf1 18. Qh1+ Ke2, etc., and black again picks up the f and g pawns.|
White couldn't play 40. Re7+ because of 40...Kd6 41. f7 d1=Q (not 41...Kxe7 42. f8=Q+ K any 43. Qxc5, winning) 42. f8=Q Qxf1+ 43. Qxf1 Kxe7, with a two-pawn advantage. But if 40...Qxe7 then 41. fxe7 Kxe7 42. Rd1 wins.
|Sep-11-05|| ||patzer2: <al wazir> I think 15. Ng3!? was a true positional sacrifice because 16. Rd2 = (according to Fritz 8's assessment) and 22. Nxd4!? leave the possibility of this forcing a sure Black win in doubt.|
|Sep-11-05|| ||al wazir: <patzer2: I think 15...Ng3!? was a true positional sacrifice because 16. Rd2 = (according to Fritz 8's assessment) and 22. Nxd4!? leave the possibility of this forcing a sure Black win in doubt.> 1. Do you mean 16. Rf2 or 16. Rd1? 2. The move 15. Ng3 may or may not have been winning, but if it initiates a forced sequence that leaves black materially even or better I don't see how it can be called a sacrifice.|
|Sep-11-05|| ||franksp: This or a similar opening line, including the forced Queen for Rook and Bishop sacrifice, appeared in a game Smyslov-Reshevsky. Smyslov won that game.|
|Sep-11-05|| ||patzer2: <al wazir> Thanks for the correction. I did intend 16. Rf2 = as the recommended followup to 15...Ng3!? Sorry for the confusion. |
IM Jeremy Silman at http://www.jeremysilman.com/chess_g... defines a sacrfice as: < The voluntary offer of material for the purpose of gaining a more favorable advantage than the material investment. Unlike a combination, a sacrifice is not a cut and dried affair--there is usually an element of uncertainty associated with it. Though a combination always has one or more sacrifices, a sacrifice need not be associated with a combination.>
Sacrfices are classified into two broad categories:
1. Sham sacrifices or pseudo sacrifices which are part of a combination to gain a clear (e.g. winning) material/positional advantage or mate.
2. Genuine sacrifices which are intendended to gain an advantage or improve the position, but for which there is a degree of uncertainty as to whether the advantage will be gained.
In my assessment, 15...Ng3!? meets the qualification of a genuine sacrifice, since it is unclear whether it leads to an advantage with best play (i.e. "element of uncertainty" associated with it). Fritz 8 @ 14 depth indicates after 15...Ng3!? 16. Rf2 Qh4 17. Qd2 Nf5 18. Qc3 = the game is level. Just because Estrin missed this line does not make 15. Ng3!? a forced sequence (i.e. combination) leading to an advantage.
However, if it can be demonstrated that 15...Ng3 leads to a forced (e.g. winning) advantage with best play, then it would still qualify as a sham sacrfice (i.e. pseudo-sacrifice associated with a combination.)
For additional discussion of the term "sacrifice" see the kibitzing at Taimanov vs Petrosian, 1953.
|Sep-11-05|| ||atrifix: The game Smyslov vs Reshevsky, 1945 is very famous and similar, although Reshevsky obviously didn't know anything about Boleslavsky vs Ragozin, 1942 or Boleslavsky vs Botvinnik, 1943. Leaving the dark-squared Bishop on, as Estrin does here, is unfavorable for White, so I assume Estrin must have had some tactical idea in mind--but it never came to pass.|
|Jun-28-06|| ||bernardchinshin: Estrin should have played 20. Bh3 taken the Bishop by 22. Nd4 Qd4 transposing into smyslov v reshevsky and boleslavsky v botvinnik|
|Jul-10-09|| ||JonDSouzaEva: I think the players are the wrong way round, Estrin beat Boey in the 1972 ICCF Championships:
See also http://archive.correspondencechess....