It's time for this position again

[yanquis1972]

firebird 1.01 default settings, which has NMV ticked & set at NMR set at 7

New game
8/p1p5/Pp1p2nk/1P1Bq1r1/2P1Pprp/1Q6/5RPP/3R3K b - - 0 1

Analysis by FireBird 1.01 x64:

1...Qf6 2.Qh3 Ne5 3.Rdf1 f3 4.gxf3 Nd3 5.Rd2
+/= (0.52) Depth: 6 00:00:00 1kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 f3 4.gxf3 Nd3 5.Rd2
+/= (0.52) Depth: 6 00:00:00 1kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 f3 4.gxf3 Nd3 5.Rd2
+/= (0.44 !) Depth: 7 00:00:00 1kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 f3 4.gxf3 Nd3 5.Rd2
+/= (0.44 !) Depth: 7 00:00:00 1kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 Rg7 4.Rd2 Re7 5.Qc3 Rg5
+/= (0.37) Depth: 7 00:00:00 1kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 Rg7 4.Rd2 Re7 5.Qc3 Rg5
+/= (0.37) Depth: 7 00:00:00 1kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 Rg7 4.Qc3 Qg6 5.Qd2
+/= (0.39) Depth: 8 00:00:00 2kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 Rg7 4.Qc3 Qg6 5.Qd2
+/= (0.39) Depth: 8 00:00:00 2kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 Rg7 4.Qc3 Qg6 5.Qd2 h3
+/= (0.39) Depth: 9 00:00:00 3kN
1...Qf6 2.Qh3 Ne5 3.Rdf1 Rg7 4.Qc3 Qg6 5.Qd2 h3
+/= (0.39) Depth: 9 00:00:00 4kN
1...Qf6 2.Qh3 Ne5 3.Qc3 Qg7 4.Qd2 h3
+/= (0.31 !) Depth: 10 00:00:00 73kN
1...Qf6 2.Qh3 Ne5 3.Qc3 Qg7 4.Qd2 h3
+/= (0.31 !) Depth: 10 00:00:00 73kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.40) Depth: 10 00:00:00 127kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.40) Depth: 10 00:00:00 133kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.32 !) Depth: 11 00:00:00 186kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.32 !) Depth: 11 00:00:00 186kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.40) Depth: 11 00:00:00 210kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.40) Depth: 11 00:00:00 232kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.40) Depth: 12 00:00:00 283kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2
+/= (0.40) Depth: 12 00:00:00 310kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2 Qg6 10.Re2 Kg5
+/= (0.32 !) Depth: 13 00:00:00 493kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Ne5 7.Qc3 c4 8.Rd1 Rg8 9.Rf2 Qg6 10.Re2 Kg5
+/= (0.32 !) Depth: 13 00:00:00 493kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Rf6 9.Qxe5 Nxe5
+/= (0.29) Depth: 13 00:00:00 786kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Rf6 9.Qxe5 Nxe5
+/= (0.29) Depth: 13 00:00:00 833kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Rf6 9.Qxe5 Nxe5
= (0.21 !) Depth: 14 00:00:00 1686kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Rf6 9.Qxe5 Nxe5
= (0.21 !) Depth: 14 00:00:00 1686kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4
+/= (0.28) Depth: 14 00:00:00 1753kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4
+/= (0.28) Depth: 14 00:00:00 1851kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4
= (0.20 !) Depth: 15 00:00:00 4313kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4
= (0.20 !) Depth: 15 00:00:00 4313kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4
+/= (0.36 --) Depth: 15 00:00:00 4870kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rf3 c4 6.Qa3 Rxb5 7.Qc1 Rg5 8.Rdf1 Qd4 9.Qxf4 c3 10.Qf8+ Rg7 11.Qh8+ Kg5
= (0.12 !) Depth: 15 00:00:01 5745kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rf3 c4 6.Qa3 Rxb5 7.Qc1 Rg5 8.Rdf1 Qd4 9.Qxf4 c3 10.Qf8+ Rg7 11.Qh8+ Kg5
= (0.12 !) Depth: 15 00:00:01 5745kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4 11.Rc2 Ne3
= (0.11) Depth: 15 00:00:01 6509kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4 11.Rc2 Ne3
= (0.11) Depth: 15 00:00:01 6512kN
1...Qf6 2.c5 bxc5 3.Be6 Ne5 4.Bxg4 Nxg4 5.Rff1 Rg6 6.Rde1 Kg7 7.Re2 Qe5 8.Qb2 Qxb2 9.Rxb2 Rf6 10.Kg1 c4 11.Rc2 Ne3
= (0.19 --) Depth: 16 00:00:01 7128kN
1...Rh5
= (0.03 !) Depth: 16 00:00:02 10180kN
1...Rh5
= (0.03 !) Depth: 16 00:00:02 10180kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 16 00:00:02 13358kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 16 00:00:02 13362kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 17 00:00:02 14823kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 17 00:00:03 15216kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 18 00:00:03 17271kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 18 00:00:03 18461kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 19 00:00:04 24708kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 19 00:00:05 27197kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 20 00:00:06 37196kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (0.00) Depth: 20 00:00:08 45845kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (-0.08 !) Depth: 21 00:00:15 90639kN
1...Rh5 2.Rf3 Rhg5 3.Rf2
= (-0.08 !) Depth: 21 00:00:15 90639kN
1...Rh5 2.Rf3 Qf6 3.Rdf1 Rhg5 4.R3f2 Rg3 5.Qd1 Re3 6.Rf3 Qb2 7.R1f2 Qc3 8.Rf1 h3 9.gxh3 Rxf3 10.Qxf3 Qb2 11.Qf2 Qc3 12.Qf3
= (0.00) Depth: 21 00:00:16 95057kN
1...Rh5 2.Rf3 Qf6 3.Rdf1 Rhg5 4.R3f2 Rg3 5.Qd1 Re3 6.Rf3 Qb2 7.R1f2 Qc3 8.Rf1 h3 9.gxh3 Rxf3 10.Qxf3 Qb2 11.Qf2 Qc3 12.Qf3
= (0.00) Depth: 21 00:00:18 103mN
1...Rh5 2.Rf3 Qf6 3.Rdf1 Rhg5 4.R3f2 Rg3 5.Qd1 Re3 6.Rf3 Qb2 7.R1f2 Qc3 8.Rf1 h3 9.gxh3 Rxf3 10.Qxf3 Qb2 11.Qf2 Qc3 12.Qf3
= (0.00) Depth: 22 00:00:24 140mN
1...Rg3
= (-0.08 !) Depth: 22 00:00:37 217mN
1...Rg3
= (-0.08 !) Depth: 22 00:00:37 217mN
1...Rg3
= (-0.16 !) Depth: 22 00:00:40 235mN
1...Rg3
= (-0.16 !) Depth: 22 00:00:40 235mN
1...Rg3
=/+ (-0.28 !) Depth: 22 00:00:44 257mN
1...Rg3
=/+ (-0.28 !) Depth: 22 00:00:44 257mN
1...Rg3
=/+ (-0.46 !) Depth: 22 00:00:52 301mN
1...Rg3
=/+ (-0.46 !) Depth: 22 00:00:52 301mN
1...Rg3 2.hxg3 hxg3 3.Rf3 Rg4 4.Kg1 Qh5 5.e5 Nxe5 6.Qc3 Qh2+ 7.Kf1 Qh1+ 8.Ke2 Qxg2+ 9.Ke1 Nxf3+ 10.Qxf3 Qh2 11.Rd2 Qh4 12.Kf1 Rg5 13.Qh1 Qxh1+ 14.Bxh1 Rh5 15.Kg1 Kg6 16.Be4+ Kf6 17.Re2 Kg5 18.Bf3 Rh7 19.Kf1 Kf6 20.Kg1 Rh8 21.Bd5 Rh7 22.Bf3
= (-0.25) Depth: 22 00:01:03 364mN
1...Rg3 2.hxg3 hxg3 3.Rf3 Rg4 4.Kg1 Qh5 5.e5 Nxe5 6.Qc3 Qh2+ 7.Kf1 Qh1+ 8.Ke2 Qxg2+ 9.Ke1 Nxf3+ 10.Qxf3 Qh2 11.Rd2 Qh4 12.Kf1 Rg5 13.Qh1 Qxh1+ 14.Bxh1 Rh5 15.Kg1 Kg6 16.Be4+ Kf6 17.Re2 Kg5 18.Bf3 Rh7 19.Kf1 Kf6 20.Kg1 Rh8 21.Bd5 Rh7 22.Bf3
= (-0.25) Depth: 22 00:01:03 364mN

may be some MP luck involved as a second run passed Rg3 over at d22.

[JVMerlino]

Many thanks to all for thoroughly looking into this position. Good to know that Larry played a move that was very controversial at the time, and it took 7+ years for engines to confirm that it was the best move for the position.

Never mind that Larry threw away a win. It's an incredible move to play OTB in a fast time control (I think Larry took 2-3 minutes to play the move, but I'm not sure).

Thanks again to all.

jm

[govert]

This position interedsted me, so I let stockfish 1.6 dig into the problem a bit, using forward/backwards sliding anaylisis.

53... Rg3 may be the best move for black, but I have not found a line yet which stockfish considers as winning. All my lines have converged to 0.00 eventually:

[Event "ICC 2 120 u"]
[Site "Internet Chess Club"]
[Date "2002.09.29"]
[Round "3"]
[White "CM9000 (Botvinnik)"]
[Black "LarryC"]
[Result "1-0"]
[BlackElo "2400"]
[ECO "A28"]
[Opening "English"]
[Variation "Four Knights, Nenarokov Variation"]
[WhiteElo "2400"]
[TimeControl "120+120"]
[Termination "normal"]
[PlyCount "143"]
[WhiteType "human"]
[BlackType "human"]

1. c4 e5 2. Nc3 Nf6 3. Nf3 Nc6 4. d4 exd4 5. Nxd4 Bb4 6. Bg5 h6 7. Bh4
Bxc3+ 8. bxc3 Ne5 9. e3 d6 10. Be2 Ng6 11. Bxf6 Qxf6 12. O-O O-O 13. Qc2
Re8 14. Rfd1 Nf8 15. Bd3 Ne6 16. Nb3 Rb8 17. a4 Qe7 18. a5 Bd7 19. a6 b6
20. Nd4 Nc5 21. Nb5 Bxb5 22. cxb5 Qf6 23. Bc4 Re5 24. Bd5 Rbe8 25. Rd4 Ne6
26. Rd2 g6 27. Ra4 Kg7 28. Rd1 Re7 29. Rb4 g5 30. Bc6 Qg6 31. Qb2 f5 32.
Qb1 Qf6 33. Bd5 f4 34. e4 Nf8 35. f3 h5 36. Qc2 Ng6 37. Qa2 Kh6 38. Qd2 Rg7
39. Qd4 g4 40. fxg4 Nh4 41. Rb2 Rxg4 42. Kh1 Ng6 43. Rf2 Qe7 44. Qd2 Reg5
45. Ra1 h4 46. c4 Qe5 47. Rc1 Kg7 48. Bc6 Qe7 49. Rcf1 Re5 50. Qc3 Kh6 51.
Bd5 Reg5 52. Qb3 Qe5

53. Rd1 Rg3 54. hxg3 hxg3
55. Rf3 Rg4
56. Kg1 Qh5
57. e5

[d]8/p1p5/Pp1p2nk/1P1BP2q/2P2pr1/1Q3Rp1/6P1/3R2K1 b - - 0 57


Here, Black seems to have 3 choices:
A.) 57... Rg5
B.) 57... Qh2+
C.) 57... Nxe5

A.) 57... Rg5:
===============
58. Qc3 Qh2+
59. Kf1 Qh1+
60. Ke2 Qxg2+
61. Kd3 Nxe5+
62. Kd4 Rg4
63. Be4! which seems to equalize.
Stockfish after 62. Rg4:
27 5:33:44 37.647.427 177 1.880.066 0,00 63.Be4 Kg5 64.Rff1 Qh2 65.Rh1 Qf2+ 66.Kd5 g2 67.Rh7 Rg3 68.Qd4 Qxd4+ 69.Kxd4 f3 70.Rxc7 Kf4 71.Rxa7 g1Q+ 72.Rxg1 Rxg1 73.Bxf3 Kxf3 74.Kd5 Rd1+ 75.Ke6 Nxc4 76.Rc7 Re1+ 77.Kd5 Rd1+ 78.Ke6


[d]8/p1p5/Pp1p3k/1P2n3/2PKBpr1/2Q2Rp1/6q1/3R4 b - - 3 63
(Position after 63. Be4)

63... Kg5
64.Rff1 Qh2
65.Rh1 Qf2+
66.Kd5 g2
67.Rh7 Rg3
68.Qd4 Qxd4+
69.Kxd4 f3 70.Rxc7 (0.00)

[d]8/p1R5/Pp1p4/1P2n1k1/2PKB3/5pr1/6p1/3R4 b - - 0 70
(Position after 70. Rxc7)

B.) 57... Qh2+
=================
58. Kf1 Qh1+
59. Ke2 Qxg2+
60. Ke1 Rg5
61. Rd2 Rxe5+
62. Kd1

[d]8/p1p5/Pp1p2nk/1P1Br3/2P2p2/1Q3Rp1/3R2q1/3K4 b - - 1 62

Stockfish:
21 22:58 614.678.803 445.817 0,00 62. ... Qh1+ 63.Kc2 Re1 64.Qa3 Qh5 65.Qc3 Qf5+ 66.Qd3 Kg5 67.Rg2 Qxd3+ 68.Rxd3 Kg4 69.Kd2 Ra1 70.Re2 Ne5 71.Rc3 f3 72.Re4+ Kh3 73.Rxe5 Ra2+ 74.Kd1 Ra1+ 75.Kc2 Ra2+ 76.Kb1 dxe5 77.Kxa2 f2 78.Rf3 Kg2 79.Rc3+ Kh2 80.Rf3 Kg2


C.) 57... Nxe5
===============
58. Kf1 Qh1
59. Ke2 Qxg2+
60. Ke1 Qh2
61. Rd2 Qh4
62. Rg2 Nxf3
63. Qxf3 (0.00)
[d] 8/p1p5/Pp1p3k/1P1B4/2P2prq/5Qp1/6R1/4K3 b - - 0 63


Black improvements anyone?

[BBauer]

Changing the following line in search.cpp from
Value v = search(pos, ss, beta, depth - 5 * OnePly, ply, false, threadID);
to
Value v = search(pos, ss, beta, depth - 6 * OnePly, ply, false, threadID);
in the Dann Corbit sources stockfish1.6.3dc
stockfish finds Nxb4 in 1h 30 min 32 sec on a 4-cpu machine running at 2GHz

20 +331 17409 486742415 Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8
21 +343 36497 1052951712 Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8
22 +331 68652 2011853360 Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8
23 +315 154550 4558110030 Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8
24 +315 330544 9741064901 Nf5 Bf6 Nxb4 Bxb2 Rxb2 Re8
24 +359 543187 15896069942 Nxb4 Bxb4 Rc7 Nf6 Rxb7

Btw "- 6 * OnePly" looks sometimes better than "- 5 * OnePly".

kind regards
Bernhard