Sacrifices

[David Dahlem]

Here are a few positions from human games with sacrificial moves. Which engines are best at finding these moves?

2rq1rk1/3bbppp/p2p1n2/1p2pP2/4P3/P1N1B1P1/1PP3BP/R2Q1R1K b - - bm Rxc3; id "Vydeslaver-Psakhis, Ramat Aviv 1998";
2r2bk1/5p2/1q2p1pp/1N1p4/Pp2bP2/1P4P1/3RQ2P/4RK2 b - - bm Rc3; id "Troianescu-Petrosian, Bucharest 1953";
nr1r1qk1/R2b2bp/3p1pp1/2pP4/2B2PPB/2N4P/1P1Q2K1/4R3 w - - bm Re6; id "Hinz-Wittstadt, Email 2005";
r2q1rk1/ppp3b1/3p3p/2nPpb2/2P3pP/2N3P1/PP1NB1P1/R2Q1RK1 w - - bm Rxf5; id "Wright-Huss, England 1973";
1k1r3r/1b3pp1/1q1p4/p2PpPb1/PpR1B2p/1N3Q2/KPP3PP/3R4 w - - bm c3; id "Kotronias-Jobava, Batumi 2002";
2rqr1k1/3n1pp1/pn1p1bbp/1p1P4/4P1P1/1P3NNP/2B1RPK1/1RBQ4 b - - bm Rxc2; id "Dominguez-Bologan, Poikovsky 2005";
2rqkb1r/1b1n1ppp/pn1pp3/1p6/3NP1P1/2NBBP2/PPP2Q1P/1K1R3R b k - bm Rxc3; id "Movsesian-Kasparov, Sarajevo 2000";
1k5r/pb3p1p/1q2rp1b/2p5/1pQ1P3/1P3N2/P3BPPP/3R1RK1 w - - bm Rd5; id "Karpov-Gelfand, Linares 1993";
1rbq1rk1/2nn1pbp/pp1p2p1/2pP4/P1P1PP2/2N1B3/1P1NQ1BP/R4R1K w - - bm e5; id "Tyomkin-Cao Sang, Budapest 1999";
r1bq1rk1/1p4bp/p2p1n2/3Ppp1n/8/2NBBPN1/PP1Q2PP/R3K2R b KQ - bm e4; id "Gheorghiu-Kasparov, Thessaloniki 1988";

[zullil]

Critter-1.2.1 (8 threads, 4GB hash, 5 minutes per position) takes a beating:

Code: Select all

Total time: 47:44, Rated time: 45:25, 1 of 10 matching

These sacrifices must be very subtle---or wrong!

[jdart]

I haven't looked at all of these, but the first one is a typical positional exchange sac. Not clear to me it is winning all by itself.

One possible followup line for White is 16. bxc3 Bc6 17. Qd3 (instead of Bg5 as in the game) Qa8 18. Bg5 Bxe4 19. Qe2! =.

[zullil]

Critter-1.2.1 (8 threads, 4GB hash, 5 minutes per position) takes a beating:

Code: Select all

Total time: 47:44, Rated time: 45:25, 1 of 10 matching

These sacrifices must be very subtle---or wrong!

No better at 15 minutes per position:

Code: Select all

Total time: 149:59, Rated time: 137:11, 1 of 10 matching

[zullil]

Here are a few positions from human games with sacrificial moves. Which engines are best at finding these moves?

[D]2rq1rk1/3bbppp/p2p1n2/1p2pP2/4P3/P1N1B1P1/1PP3BP/R2Q1R1K b - - bm Rxc3; id "Vydeslaver-Psakhis, Ramat Aviv 1998";
[D]2r2bk1/5p2/1q2p1pp/1N1p4/Pp2bP2/1P4P1/3RQ2P/4RK2 b - - bm Rc3; id "Troianescu-Petrosian, Bucharest 1953";
[D]nr1r1qk1/R2b2bp/3p1pp1/2pP4/2B2PPB/2N4P/1P1Q2K1/4R3 w - - bm Re6; id "Hinz-Wittstadt, Email 2005";
[D]r2q1rk1/ppp3b1/3p3p/2nPpb2/2P3pP/2N3P1/PP1NB1P1/R2Q1RK1 w - - bm Rxf5; id "Wright-Huss, England 1973";
[D]1k1r3r/1b3pp1/1q1p4/p2PpPb1/PpR1B2p/1N3Q2/KPP3PP/3R4 w - - bm c3; id "Kotronias-Jobava, Batumi 2002";
[D]2rqr1k1/3n1pp1/pn1p1bbp/1p1P4/4P1P1/1P3NNP/2B1RPK1/1RBQ4 b - - bm Rxc2; id "Dominguez-Bologan, Poikovsky 2005";
[D]2rqkb1r/1b1n1ppp/pn1pp3/1p6/3NP1P1/2NBBP2/PPP2Q1P/1K1R3R b k - bm Rxc3; id "Movsesian-Kasparov, Sarajevo 2000";
[D]1k5r/pb3p1p/1q2rp1b/2p5/1pQ1P3/1P3N2/P3BPPP/3R1RK1 w - - bm Rd5; id "Karpov-Gelfand, Linares 1993";
[D]1rbq1rk1/2nn1pbp/pp1p2p1/2pP4/P1P1PP2/2N1B3/1P1NQ1BP/R4R1K w - - bm e5; id "Tyomkin-Cao Sang, Budapest 1999";
[D]r1bq1rk1/1p4bp/p2p1n2/3Ppp1n/8/2NBBPN1/PP1Q2PP/R3K2R b KQ - bm e4; id "Gheorghiu-Kasparov, Thessaloniki 1988";

[David Dahlem]

Critter-1.2.1 (8 threads, 4GB hash, 5 minutes per position) takes a beating:

Code: Select all

Total time: 47:44, Rated time: 45:25, 1 of 10 matching

These sacrifices must be very subtle---or wrong!

These positions came from the book "Chess Cafe Puzzle Book 2 by Karsten Muller". There were some that were solved by Houdini in less than 30 seconds. So i didn't include them on the basis they were too "easy".

The games with Mullers annotations for these 10 positions -

[Event "ISR-ch"]
[Site "Ramat Aviv"]
[Date "1998.11.08"]
[Round "1.1"]
[White "Vydeslaver, Alik"]
[Black "Psakhis, Lev"]
[Result "0-1"]
[WhiteElo "2405"]
[BlackElo "2560"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "2rq1rk1/3bbppp/p2p1n2/1p2pP2/4P3/P1N1B1P1/1PP3BP/R2Q1R1K b - - 0 15"]

{Positional Exchange Sacrifice Difficulty:2} 15... Rxc3 $1 16. bxc3 Bc6 17.
Bg5 (17. Qd3 Qa8 18. Bg5 Bxe4 19. Qe2 (19. Bxe4 $2 Nxe4 $19 {(Atlas in CBM 68)}
) 19... Bxg2+ 20. Qxg2 d5 $15) 17... Nxe4 $1 ({
It is better to keep the light-squared bishops on the board as} 17... Bxe4 18.
Bxe4 Nxe4 19. Bxe7 Qxe7 20. Qd5 Nf6 21. Qc6 {is approximately equal, since it
is easier for White's rooks to play a good role.}) 18. Bxe7 Qxe7 19. f6 {
Psakhis has calculated that he can neutralize this tactical shot.} 19... Qb7
20. fxg7 Rc8 $1 21. Qg4 Nd2 22. Rf2 Bxg2+ 23. Rxg2 Rxc3 24. Qg5 (24. Qh4 Ne4
25. Re1 Rc4 $17) 24... Ne4 25. Qd8+ Kxg7 26. Re1 $2 (26. Kg1 $17) 26... Rxc2 ({
The text move is also very strong, but Psakhis could have forced mate with}
26... Nf2+ 27. Kg1 Nh3+ 28. Kh1 Rxc2 $19 {
Two points for 15...Rxc3! 16.bxc3 Bc6.}) 0-1

[Event "Bucharest"]
[Site "Bucharest"]
[Date "1953.??.??"]
[Round "10"]
[White "Troianescu, Octavio"]
[Black "Petrosian, Tigran"]
[Result "0-1"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "2r2bk1/5p2/1q2p1pp/1N1p4/Pp2bP2/1P4P1/3RQ2P/4RK2 b - - 0 35"]

{Positional Exchange Sacrifice Difficulty:2} 35... Rc3 $1 {
Offering a second exchange sac!} 36. Nxc3 ({If White declines the second gift by} 36. Nd4 {then after} 36... Bc5 37. Red1 Bxd4 38. Rxd4 Bf3 $19 {he loses.}) 36... bxc3 37. Rc2 Qxb3 38. Rec1 Bb4 39. g4
{White can only watch and wait on the queenside.} 39... Bxc2 40. Rxc2 Qxa4 {
The game was adjourned in this position (younger players should ask a veteran
player what this means). With three pawns (two connected and passed) for the
exchange, Black is winning.} 41. f5 exf5 $1 42. gxf5 g5 43. h4 Bc5 $1 44. hxg5
Qf4+ 45. Ke1 Qg3+ 46. Kd1 Qg1+ 47. Qe1 Qxe1+ 48. Kxe1 hxg5 49. Ke2 ({
Should White wish to end the game early he could play} 49. Rxc3 Bb4) 49... Bd4
$1 50. Ra2 Kg7 51. Kd3 Be5 $1 52. Ra5 Kf6 53. Rxd5 Kxf5 54. Ke3 f6 55. Rc5 Kg4
56. Rc4+ Kg3 57. Ke4 g4 {Two points for 35...Rc3!.} 0-1

[Event "ML-220-BdF-Email"]
[Site "MyTown"]
[Date "2005.05.10"]
[Round "?"]
[White "Hinz, Juergen"]
[Black "Wittstadt, Renato"]
[Result "*"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "nr1r1qk1/R2b2bp/3p1pp1/2pP4/2B2PPB/2N4P/1P1Q2K1/4R3 w - - 0 27"]

{Positional Exchange Sacrifice Difficulty:3} 27. Re6 $3 {This maximizes
the pressure against Black's weak spots d6 and f6, which is reminiscent of the
teachings of Steinitz!} (27. Bd3 $6 {gets only one point because of} 27... Nb6
28. f5 gxf5 29. gxf5 Kh8 30. Kh1 Re8 31. Rg1 Re7 $14 {
with only a slight advantage.}) (27. b3 $2 {let's Black off the hook:} 27...
Nb6 28. Bb5 Bxb5 29. Nxb5 Nc8 30. Ra5 Re8 31. Re6 f5 32. gxf5 gxf5 33. Qd3 Rxe6
34. dxe6 Bf6 $132 {with counterplay.}) (27. Bb5 {
gets only two points as it allows} 27... Bxb5 (27... Nb6 28. Re6 {transposes.})
28. Nxb5 Rxb5 29. Ree7 Rdb8 {which gives Black good counterplay, e.g.} 30. Qe3
Rxb2+ 31. Bf2 Nb6 32. Rxg7+ Qxg7 33. Rxg7+ Kxg7 34. Qe7+ Kg8 35. Qxd6 Re8)
27... Nb6 ({If} 27... Rb4 {then} 28. b3 Nb6 29. Qe3 Nxc4 30. bxc4 Rxc4 $2 31.
Rxd7 $18) ({Or} 27... Kh8 28. Ne4 Nb6 29. Bxf6 Nxc4 30. Qc3 Rb4 (30... Rxb2+
31. Kg3 Rb4 32. Nxd6 $16) 31. Bxg7+ Qxg7 32. Nf6 $16 {
in both instances with big advantage to White.}) 28. Bb5 Ra8 $6 {Not the best.}
({Black should try to relieve the pressure with} 28... Kh8 $5 {
If White then plays for the win of a pawn with} 29. Bxd7 {after} 29... Rxd7 30.
Rxd7 Nxd7 31. Qe2 Bh6 32. Ne4 (32. Bg3 f5 33. g5 Bg7 34. Nb5 Nb6 $132) 32...
Bxf4 33. Bxf6+ (33. Nxf6 Ne5 34. Ne4 g5 35. Bxg5 Bxg5 36. Nxg5 Qf4 $132) 33...
Nxf6 34. Rxf6 Qh6 35. Nxd6 Bxd6 36. Rxd6 Qg7 $14 {+/-, White is still for
choice, but Black may have some drawing possibilities because of the reduced
number of pawns on the board and the exposed position of the white king.}) (
28... Bxb5 {is met by} 29. Nxb5 Nc4 30. Qe1 Rxb5 31. Rxf6 Rxb2+ 32. Kh1 Qe8 33.
Re6 Qb5 34. Ree7 $18) 29. Rxa8 Nxa8 ({If} 29... Rxa8 {White wins with} 30. Bxd7
Nxd7 31. Ne4 Ra2 32. Nxd6 f5 33. Nc4 fxg4 34. hxg4 Qa8 35. Re7 Nf6 36. Kg3 $18)
30. Bxd7 Rxd7 31. Nb5 Nc7 ({Or} 31... Nb6 32. Qe1 Rd8 33. Qe4 Nc8 34. f5 $16)
32. Nxc7 Rxc7 33. Qe2 Kf7 ({If Black tries to meet the threat of 34.Re8 by}
33... Rc8 {then White squeezes him with} 34. Re7 Kh8 35. Qe6 Rb8 36. b3 $18 {
and Black can resign with a clear conscious.}) 34. f5 Rb7 35. Bg3 {The final st
age of the assault. The white bishop regroups to the long diagonal. All Black
can really do is watch.} 35... Rb6 36. Be1 Rb7 37. Bc3 g5 38. Qa6 Qb8 39. Qxd6
Rxb2+ 40. Bxb2 Qxb2+ 41. Kf1 $18 {
and White went on to win. Three points for 27.Re6!!.} *

[Event "England"]
[Site "?"]
[Date "1973.??.??"]
[Round "?"]
[White "Wright, Josie"]
[Black "Huss, Andreas"]
[Result "1-0"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "r2q1rk1/ppp3b1/3p3p/2nPpb2/2P3pP/2N3P1/PP1NB1P1/R2Q1RK1 w - - 0 1"]

{Positional Exchange Sacrifice Difficulty:2} 1. Rxf5 $1 $16 {This strong
sacrifice eliminates Black's best piece. Now White will have unchallenged play
on the light squares.} (1. Bxg4 $6 {gives Black dangerous counterplay with the
passed e-pawn and the pair of bishops, e.g.} 1... Bd3 2. Be2 (2. Rxf8+ Qxf8 3.
Qf3 Qe7 4. Nce4 Rf8 5. Qe3 Nxe4 6. Qxd3 Nc5 7. Qe3 e4 $132) 2... Bh7 (2...
Rxf1+ 3. Qxf1 (3. Nxf1 e4 4. Ne3 Qf6 $36) 3... Bh7 (3... e4 $2 4. Bxd3 exd3 5.
Nb3 Qe8 6. Nxc5 Qe3+ 7. Qf2 Qxc5 8. Qxc5 dxc5 9. Rd1 $16) 4. Qf3 Qd7 5. Rf1 Rf8
6. Qe3 $14) 3. Rxf8+ Qxf8 4. Nb3 e4 5. Nxc5 dxc5 6. Qb3 b6 7. Rf1 Bd4+ 8. Kh2
Qe7 $132) 1... Rxf5 2. Bxg4 Rf8 3. Nde4 Nxe4 {
This exchanges White's superflous knight.} ({But} 3... Nd7 4. Be6+ Kh8 5. Qh5 {
is also very promising for White.}) 4. Nxe4 Qe7 (4... c6 5. Be6+ Kh8 6. Qh5
Qb6+ 7. Kh2 Qxb2 $2 {plays witrh fire:} 8. Qg6 Qc2 9. Rc1 Qd3 10. Rc3 Qb1 (
10... Qd1 11. Nxd6 $18) 11. Rb3 Qc2 12. Rxb7 $18) 5. Be6+ Kh8 6. a4 a5 7. Ra3
c6 8. Qg4 cxd5 9. Bxd5 Rad8 10. Rb3 b5 11. axb5 a4 12. Rb4 a3 13. bxa3 Qa7+ 14.
b6 Qxa3 15. Rb1 Qd3 16. Rd1 Qe3+ 17. Kh2 Qxb6 18. Qg6 Qc7 19. Ng5 hxg5 20. Be4
Bf6 21. Qh6+ Kg8 22. Bd5+ Rf7 23. Qxf6 Rdf8 24. Rf1 {One point for 1.Rxf5! and
the second for the assessment that White is clearly on top.} 1-0

[Event "EU-ch 3rd"]
[Site "Batumi"]
[Date "2002.06.16"]
[Round "5"]
[White "Kotronias, Vasilios"]
[Black "Jobava, Baadur"]
[Result "1-0"]
[WhiteElo "2580"]
[BlackElo "2566"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "1k1r3r/1b3pp1/1q1p4/p2PpPb1/PpR1B2p/1N3Q2/KPP3PP/3R4 w - - 0 23"]

{Blockade, Positional Exchange Sacrifice Difficulty:3} 23. c3 $1 $16 {
The light-square blockade and dark-square breakthrough is quite typical.} 23...
Be3 ({After} 23... Rc8 {White has the shot} 24. Rc6 $3 {which decides the issue in the long run:} 24... Bxc6 25. dxc6 bxc3 26. Rd5 (26. Qxc3 $2 {is met by} 26... Qb4) 26... Qxc6 (26... Qe3 $2 27. Rb5+ Kc7 28. Rb7+ Kd8 29. Qd1 Be7 30. Qd5 Ke8 31. f6 gxf6 32. Bg6 $18) 27. Rb5+ Qxb5 28. axb5 d5
29. bxc3 dxe4 30. Qxe4 $16) 24. cxb4 axb4 25. Re1 Bf4 26. Bd3 Ka8 $6 27. a5 Qa7
28. Rc7 Qb8 29. Rxf7 Qc8 30. Bb5 Rhf8 31. Rxg7 Rxf5 32. a6 $1 e4 33. axb7+ Qxb7
34. Rxb7 exf3 35. Bc6 {One point for 23.c3! and two more if you spotted 23...Rc8 24.Rc6!!.} 1-0

[Event "Poikovsky Karpov 6th"]
[Site "Poikovsky"]
[Date "2005.03.01"]
[Round "4"]
[White "Dominguez, Lenier"]
[Black "Bologan, Viktor"]
[Result "0-1"]
[ECO "C91"]
[WhiteElo "2661"]
[BlackElo "2683"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "2rqr1k1/3n1pp1/pn1p1bbp/1p1P4/4P1P1/1P3NNP/2B1RPK1/1RBQ4 b - - 0 24"]

{Positional Exchange Sacrifice Difficulty:4} 24... Rxc2 $3 {"Clear exchange
sacrifice. It was not so clear for me from the concrete point of view but I
was sure that positionally it should be enough at least for compensation. Now
after both takes black gains back a pawn and keeps some other threats forcing
white for new give ups." (Bologan in CBM 106)} (24... Qc7 $6 25. Nd4 $14) 25.
Qxc2 (25. Rxc2 $6 Nc5 $36) 25... Nxd5 26. Bd2 Qa8 $1 {Black has enough
compensation and his position is much easier to play than White's, which is
not unimportant from a practical point of view!} 27. Rbe1 (27. Nf5 Bxf5 28.
gxf5 b4 29. Qc4 Nc3 30. Bxc3 bxc3 31. Rd1 Rc8 32. Qb4 Rc6 $36) 27... b4 28. Nf5
Bxf5 29. gxf5 Nc3 30. Bxc3 bxc3 31. Rd1 $2 (31. Qd3 $142 $132) 31... Nc5 32.
Rxd6 Rxe4 33. Rxe4 Nxe4 34. Rxa6 $2 Qxa6 35. Qxe4 Qa2 36. Qe8+ Kh7 37. Qxf7 Qe2
38. Ng1 Qe4+ 39. f3 Qxf5 40. Qc4 Qg5+ 41. Kf2 Qd2+ 42. Ne2 c2 43. h4 Bd4+ 44.
Kg3 h5 45. f4 Qe3+ 46. Kg2 Bc3 47. Qb5 g6 48. f5 Qe4+ 49. Kg3 Be5+ 50. Kf2
Qxf5+ 51. Kg2 Qe4+ 52. Kf2 Bd4+ 0-1

[Event "Bosna SuperGM"]
[Site "Sarajevo"]
[Date "2000.05.29"]
[Round "11"]
[White "Movsesian, Sergei"]
[Black "Kasparov, Garry"]
[Result "0-1"]
[WhiteElo "2668"]
[BlackElo "2851"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "2rqkb1r/1b1n1ppp/pn1pp3/1p6/3NP1P1/2NBBP2/PPP2Q1P/1K1R3R b k - 0 13"]

{Another typical sacrifice is ...Rxc3 in the Sicilian Defense:#} 13... Rxc3 $5
{As compensation Black gets strong knight outposts at a4, c4 and c5 and the
d6-d5 break to fuel his attack.} 14. bxc3 Qc7 15. Ne2 Be7 16. g5 O-O 17. h4 Na4
$1 {The knight is very annoying for White.} ({
It is too early to open the position with} 17... d5 $2 18. h5 dxe4 19. Bxe4
Bxe4 20. fxe4 Nc4 21. Bc1 b4 22. cxb4 Bxb4 23. Rh3 {
and White was clearly better in S.Zagrebelny-C.Lingnau, Berlin 1993.}) 18. Bc1
$6 (18. h5 Ne5 19. Bd4 {was more critical.}) 18... Ne5 19. h5 d5 $1 {
Now the time is ripe.} 20. Qh2 Bd6 21. Qh3 Nxd3 22. cxd3 b4 $1 {
This speeds up Black's attack.} 23. cxb4 (23. c4 dxc4 24. dxc4 Be5 $40) 23...
Rc8 24. Ka1 dxe4 25. fxe4 {#} 25... Bxe4 $1 {The decisive blow.} 26. g6 (26.
dxe4 Be5+ 27. Rd4 Bxd4+ 28. Nxd4 Qxc1+ 29. Rxc1 Rxc1#) (26. Rhg1 Qc2 $19) 26...
Bxh1 27. Qxh1 Bxb4 28. gxf7+ (28. gxh7+ Kh8 $19) 28... Kf8 {
#Kasparov uses the f7-pawn as shield for his king.} 29. Qg2 Rb8 30. Bb2 (30.
Bd2 Ba3 $19) 30... Nxb2 31. Nd4 Nxd1 $1 {A nice final touch.} 32. Nxe6+ Kxf7 {
and Movsesian resigned because of} 33. Qxg7+ Kxe6 34. Qxc7 Bc3+ $19 0-1

[Event "Linares"]
[Site "Linares"]
[Date "1993.??.??"]
[Round "6"]
[White "Karpov, Anatoly"]
[Black "Gelfand, Boris"]
[Result "1-0"]
[WhiteElo "2725"]
[BlackElo "2690"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "1k5r/pb3p1p/1q2rp1b/2p5/1pQ1P3/1P3N2/P3BPPP/3R1RK1 w - - 0 20"]

{Positional Exchange Sacrifice Difficulty: 5} 20. Rd5 $3 {A stunner. This
type of exchange sacrifice has been seen before, but it is more common when
the destination square for the rook is covered by two pawns (i.e., there would
be another pawn on c4). Karpov has evaluated the position very well.} (20. Bd3
$2 {Let's Black off the hook.} 20... Rg8 21. Nh4 (21. Rfe1 $2 f5 22. Nd2 (22.
h3 $2 Qc6 $19) 22... Bxd2 23. Rxd2 fxe4 $17) 21... Rg4 22. Nf5 Bxe4 23. Bxe4
Rgxe4 $132) 20... Rhe8 ({If} 20... Bxd5 {then} 21. exd5 Re7 22. Rd1 $16 {
(Karpov). This position was analyzed in John Watson's excellent book "Secrets
of Modern Chess Stratey." Several factors were noted that justified the offer
of the exchange: (1) White has all the possible entry squares in the e-file
covered; (2) The bishops of opposite color are not performing equally, in
particular White's light-square bishop can go to the b1-h7 diagonal from where
it will support the invasion of the black queenside, particular from the nice
f5-square; (3) White has a strong central pawn; and (4) the black king is
exposed and the white knight is also able to go to f5, where it dominates the
board.}) 21. Bd3 Rd8 22. Rd1 Red6 23. Be2 Bxd5 {
Black cannot sit idly by while White improves his position.} (23... Rxd5 $2 {
is not good because of} 24. exd5 Qd6 25. Qh4 $16) 24. exd5 Qb7 {
Black might even have winning chances, if he could rid himself of the d5-pawn.}
25. Qh4 Bf8 26. Bc4 Rxd5 {The d5-pawn is no longer a bone in Black's throat,
but a bad bishop vs. good knight, the exposed black king and poor black pawn
structure add up for a very difficult defense for Black.} 27. Bxd5 Rxd5 28. Re1
Rd8 29. Qxf6 Qc7 30. g3 Bd6 {All else being equal, the pawns are placed on the
same color as the opposing bishop, so as to limit its scope.} 31. Ng5 Rd7 32.
Re8+ Kb7 33. Ne4 Qc6 34. Qf5 Be7 35. Kg2 Rc7 36. Rh8 Qg6 37. Qd5+ Qc6 38. Qxc6+
Kxc6 39. Rxh7 {A pawn up, better pawn structure and an excellent square at c4
for the knight add up to a winning position for White.} 39... Kd5 40. Nd2 Bf6
41. Nc4 Kd4 42. Rh6 Rc6 43. g4 Re6 44. h4 Kd5 45. g5 {Five points for 20.Rd5!!.
} 1-0

[Event "EUCup G6"]
[Site "Budapest"]
[Date "1999.10.13"]
[Round "3.5"]
[White "Tyomkin, Dimitri"]
[Black "Cao Sang"]
[Result "1-0"]
[WhiteElo "2495"]
[BlackElo "2501"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "1rbq1rk1/2nn1pbp/pp1p2p1/2pP4/P1P1PP2/2N1B3/1P1NQ1BP/R4R1K w - - 0 21"]

{Creating an outpost square with the following positional pawn sacrifice is
quite typical in Benoni-like structures:#} 21. e5 $1 dxe5 22. f5 {
White has created an outpost on e4 for one of his knights.} 22... Ne8 {
It may seem illogical to exchange the superfluous white knight, but Black's
task is very difficult anyway.} (22... Qh4 23. Nde4 Bh6 24. Bxh6 Qxh6 25. Rf3 {
and White is for choice.}) 23. Nde4 Ndf6 (23... gxf5 24. Rxf5 Ndf6 25. Nxf6+
Nxf6 26. Rg5 Ne8 27. a5 $36 {(Tyomkin)}) 24. fxg6 fxg6 {#} 25. a5 $1 {
A typical undermining strategy follows, which destroys Black's queenside:}
25... Bg4 26. Qd2 Nxe4 27. Nxe4 Nd6 28. Nxd6 Qxd6 29. b4 $1 e4 30. Rxf8+ Rxf8
31. Rg1 cxb4 32. Bxe4 Bc3 33. Qg2 Bf5 (33... Bh5 34. axb6 Qe5 35. d6 Qxd6 36.
c5 Qe5 37. c6 Bf3 38. Bxf3 Qxe3 39. Bd5+ Kg7 40. Rf1 Bf6 41. Qf2 Qe5 42. Rd1
$18) 34. Bxf5 Rxf5 35. axb6 Qe7 36. Bf2 Qf7 37. Bc5 b3 38. Rd1 b2 39. Bg1 Rg5 (
39... Bf6 40. Rb1 (40. Qe4 $2 {is met by} 40... Be5 (40... Re5 $2 41. Qg4 Bg5
42. d6 Bc1 43. d7 b1=Q 44. d8=Q+ Re8 45. Rd7 $18)) 40... Qd7 41. Rxb2 Bxb2 42.
Qxb2 {and White's passed pawns should win the game.}) 40. b7 Be5 $2 (40... Qxb7
41. Qxg5 b1=Q 42. Rxb1 Qxb1 43. Qg4 Qd3 44. Kg2 Qd2+ 45. Bf2 a5 46. Qe4 $16)
41. Qxg5 Qf3+ 42. Qg2 Qxd1 43. Qxb2 $1 1-0

[Event "Thessaloniki (ol)"]
[Site "?"]
[Date "1988.??.??"]
[Round "?"]
[White "Gheorghiu, Florin"]
[Black "Kasparov, Garry"]
[Result "0-1"]
[WhiteElo "2485"]
[BlackElo "2760"]
[Annotator "Mueller,Karsten"]
[SetUp "1"]
[FEN "r1bq1rk1/1p4bp/p2p1n2/3Ppp1n/8/2NBBPN1/PP1Q2PP/R3K2R b KQ - 0 15"]

{#} 15... e4 $5 {A typical pawn sacrifice to create a strong outpost square on
e5. Kasparov bides his time before occupying it:} 16. Nxh5 Nxh5 17. fxe4 f4 $1
18. Bf2 Bg4 19. h3 ({After} 19. Be2 {
Kasparov gives a dynamic line that reflects his style well:} 19... Bxe2 20.
Qxe2 f3 $1 21. gxf3 Nf4 22. Qd2 (22. Qf1 Rc8 23. Rg1 Ng6 $44) 22... Ng2+ 23.
Kf1 Nh4 24. Bxh4 Qxh4 $40 {Informant 46/802}) (19. O-O f3 20. Be3 Qh4 21. Qf2
Qe7 22. Rac1 Nf4 $44) 19... Bd7 20. O-O-O Be5 21. Kb1 Qf6 22. Be2 Ng3 23. Bxg3
$6 (23. Rhe1 Bxc3 24. Qxc3 Qxc3 25. bxc3 Nxe4 26. Bd4 Bf5 27. Kb2 Rac8 {
is slightly better for White. (Kasparov)}) 23... fxg3 24. Bf3 Rac8 25. Ne2 Qg6
(25... Rc5 $5 26. Rc1 Rfc8 27. Bg4 Bxg4 28. hxg4 Qg6 {
also gives Black very good compensation.}) 26. Rc1 Rxc1+ 27. Qxc1 Rc8 28. Qe3
$6 Qf6 29. Qd2 Rc5 30. Nc1 $2 {
This allows Black's whole army to join the attack.} (30. Rc1 {
to reduce the attacking potential was called for, e.g.} 30... b6 31. Rxc5 bxc5
32. Nc1 Bxh3 33. Nd3 Bd7 34. Nxe5 Qxe5 {and Black is for choice.}) 30... Bf4
31. Qb4 (31. Qd3 Bb5 32. Qa3 Qd4 33. Nb3 Qd3+ 34. Ka1 Rc7 35. Qb4 Qc2 36. Qe1
Qf2 $19) 31... Bb5 32. Nb3 Bd3+ 33. Ka1 Rc2 34. Rb1 (34. Qd4 Be5 35. Qxd3 Rxb2
$19 {(Kasparov)}) 34... Be5 35. Nc1 Bxb2+ 36. Qxb2 Qxb2+ 0-1