Test position Kaidanov-J.Polgar

[Marc MP]

Here is a position from their sicilian match:

[d]b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - - 0 1

I think Judith's move 31... e3! is best here, but the engines I tried can't find it on my poor hardware within 10 minutes. Any takers to verify that?

[Event "Sicilian Theme Match"]
[Site "Hilton Head USA"]
[Date "2010.2.22"]
[Round "1"]
[White "Kaidanov, G."]
[Black "Polgar, Ju"]
[Result "1-0"]
[WhiteElo "2583"]
[BlackElo "2687"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Bxf6 gxf6 10. Nd5 f5 11. Bd3 Be6 12. c3 Bg7 13. Nxb5 axb5 14. Bxb5 Bd7 15. exf5 Nb8 16. a4 O-O 17. O-O Bxf5 18. Qf3 Be6 19. Ne7+ Qxe7 20. Qxa8 d5 21. a5 Nd7 22. Qa7 Qd6 23. a6 e4 24. Bxd7 Bxd7 25. Qe3 f5 26. Rfd1 Bc6 27. a7 Ba8 28. Qe2 Qc5 29. Qa6 f4 30. Ra5 Qe7 31. Raxd5 e3 32. Qd6 exf2+ 33. Kf1 Qe3 34. R5d3 Bxg2+ 35. Kxg2 f3+ 36. Kh3 Qe2 37. a8Q f1Q+ 38. Rxf1 Qxf1+ 39. Kh4 Qe1+ 40. Kh5 1-0

[Terry McCracken]

Here is a position from their sicilian match:

[d]b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - - 0 1

I think Judith's move 31... e3! is best here, but the engines I tried can't find it on my poor hardware within 10 minutes. Any takers to verify that?

[Event "Sicilian Theme Match"]
[Site "Hilton Head USA"]
[Date "2010.2.22"]
[Round "1"]
[White "Kaidanov, G."]
[Black "Polgar, Ju"]
[Result "1-0"]
[WhiteElo "2583"]
[BlackElo "2687"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Bxf6 gxf6 10. Nd5 f5 11. Bd3 Be6 12. c3 Bg7 13. Nxb5 axb5 14. Bxb5 Bd7 15. exf5 Nb8 16. a4 O-O 17. O-O Bxf5 18. Qf3 Be6 19. Ne7+ Qxe7 20. Qxa8 d5 21. a5 Nd7 22. Qa7 Qd6 23. a6 e4 24. Bxd7 Bxd7 25. Qe3 f5 26. Rfd1 Bc6 27. a7 Ba8 28. Qe2 Qc5 29. Qa6 f4 30. Ra5 Qe7 31. Raxd5 e3 32. Qd6 exf2+ 33. Kf1 Qe3 34. R5d3 Bxg2+ 35. Kxg2 f3+ 36. Kh3 Qe2 37. a8Q f1Q+ 38. Rxf1 Qxf1+ 39. Kh4 Qe1+ 40. Kh5 1-0

Rybka 3 sees it straight away on a Q6600.

[yanquis1972]

what a loaded position -- analysing for a half-hour with IDeA without forcefeeding moves nothing better than a draw is popping up for e3, whereas the simple BxR gives an =/-. i'll come back to it later along w/ some straight engine analysis. Qe3 seems poor and obviously the bishop sac was unsound, which throws the move into question, so i don't doubt that IDeA may be correct.

[metax]

Well... my engine is - as always - ultra slow in this position, but it does find ...e3 and I don't know whether this is good or bad.


FEN: b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - - 0 1

ChessMind:
1/13 00:00 0 0 +2,76 La8xd5 Td1xd5
1/14- 00:00 0 0 +1,75 e4e3
1/14 00:00 0 0 +1,77 e4e3
2/19 00:00 8.367 54.000 +1,99 e4e3 Td5h5 e3xf2+ Kg1f1 De7e4
3/20 00:00 18.209 93.000 +2,35 e4e3 Td5h5 Kg8h8 Kg1f1 e3e2+
4/21 00: +1,04 e4e3 Td5h5 Kg8h8 f2xe3 f4xe3
5/23 00:01 106.059 184.000 +1,35 e4e3 Td5h5 e3xf2+ Kg1f1 De7e8 Th5g5 Tf8f7
6/27 00:06 1.260.030 241.000 +0,37 e4e3 Td5a5 e3xf2+ Kg1xf2 f4f3 Da6c4+ Kg8h8 g2g3 Tf8e8
7/28 00:14 3.474.843 248.000 +0,23 e4e3 Td5a5 e3xf2+ Kg1f1 f4f3 g2xf3 Tf8xf3 Ta5h5 Tf3f8 Da6c4+
8/33 00:31 7.738.693 249.000 +0,33 e4e3 Td5d3 e3e2 Td1e1 De7g5 g2g3 Dg5g4 Te1c1 f4xg3 Da6a2+

edit: Arena is bad in formatting analyses as plaintext.

[Eelco de Groot]

Here is a position from their sicilian match:

[d]b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - - 0 1

I think Judith's move 31... e3! is best here, but the engines I tried can't find it on my poor hardware within 10 minutes. Any takers to verify that?

[Event "Sicilian Theme Match"]
[Site "Hilton Head USA"]
[Date "2010.2.22"]
[Round "1"]
[White "Kaidanov, G."]
[Black "Polgar, Ju"]
[Result "1-0"]
[WhiteElo "2583"]
[BlackElo "2687"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Bxf6 gxf6 10. Nd5 f5 11. Bd3 Be6 12. c3 Bg7 13. Nxb5 axb5 14. Bxb5 Bd7 15. exf5 Nb8 16. a4 O-O 17. O-O Bxf5 18. Qf3 Be6 19. Ne7+ Qxe7 20. Qxa8 d5 21. a5 Nd7 22. Qa7 Qd6 23. a6 e4 24. Bxd7 Bxd7 25. Qe3 f5 26. Rfd1 Bc6 27. a7 Ba8 28. Qe2 Qc5 29. Qa6 f4 30. Ra5 Qe7 31. Raxd5 e3 32. Qd6 exf2+ 33. Kf1 Qe3 34. R5d3 Bxg2+ 35. Kxg2 f3+ 36. Kh3 Qe2 37. a8Q f1Q+ 38. Rxf1 Qxf1+ 39. Kh4 Qe1+ 40. Kh5 1-0

Rainbow Serpent thinks that after 31... BxRd5 White can keep the two passed pawns on b2 and c3 but that they are not worth a full Bishop, so Black is ahead. Connected passers are not tuned but if I decrease the bonus for connected passers this should be even more an advantage for Black, so I don't think it is a wrong tuning mattter.


[d]b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - -

Engine: Rainbow Serpent 1.6.3s(dc) Build 139 (Athlon 2009 MHz, 128 MB)
by Tord Romstad, Marco Costalba, Joona Kiiski Modifications: Dann Corbit

1.00 0:00 -1.53 31...Bxd5 (459) 4

2.00 0:00 -0.92 31...Bxd5 32.Rxd5 Ra8 (782) 7

3.00 0:00 -0.56 31...Bxd5 32.Rxd5 Ra8 33.Ra5 (2.182) 19

4.00 0:00 -0.68 31...Bxd5 32.Rxd5 Ra8 33.Ra5 Bf6
34.Qc4+ Kf8 (3.492) 31

5.00 0:00 -0.72 31...Bxd5 32.Rxd5 Ra8 33.Ra5 Bf6
34.Rf5 (10.339) 82

5.00 0:00 -0.40 31...e3 32.Qc4 exf2+ 33.Kxf2 Qxa7+
34.Rc5+ Rf7 35.Kg1 (22.857) 145

6.00 0:00 -1.09-- 31...e3 32.Qc4 exf2+ 33.Kf1 Qe6
34.R5d4 (49.856) 245

7.00 0:00 +0.28 31...e3 32.Qc4 exf2+ 33.Kf1 Kh8
34.Qe2 Qxa7 35.Rd8 Bc6 36.Rxf8+ Bxf8
37.Qxf2 (220.194) 413

8.00 0:01 +0.92 31...e3 32.Qc4 exf2+ 33.Kf1 Kh8
34.Qe2 Qc7 35.R5d3 f3 36.gxf3 Qxa7
37.Qxf2 (841.506) 543

9.01 0:01 0.00 31...e3 32.Qc4 exf2+ 33.Kf1 Kh8
34.Qe2 Qc7 35.R5d3 f3 36.gxf3 Qxh2
37.Qxf2 Qh1+ 38.Qg1 Rxf3+ 39.Rxf3 Qxf3+
40.Ke1 Qe4+ 41.Kf1 Qf3+ (953.944) 540

10.01 0:03 0.00 31...e3 32.Qc4 exf2+ 33.Kf1 Kh8
34.Qe2 Qc7 35.R5d3 f3 36.gxf3 Qxh2
37.Qxf2 Qh1+ 38.Qg1 Rxf3+ 39.Rxf3 Qxf3+
40.Ke1 Qe4+ 41.Kf1 Qf3+ (1.816.068) 550

11.01 0:05 0.00 31...e3 32.Qc4 exf2+ 33.Kf1 Kh8
34.Qe2 Qc7 35.R5d3 f3 36.gxf3 Qxh2
37.Qxf2 Qh1+ 38.Qg1 Rxf3+ 39.Rxf3 Qxf3+
40.Ke1 Qe4+ 41.Kf1 Qf3+ (2.820.783) 543

12.01 0:07 0.00 31...e3 32.Qc4 exf2+ 33.Kf1 Kh8
34.Qe2 Qc7 35.R5d3 f3 36.gxf3 Qxh2
37.Qxf2 Qh1+ 38.Qg1 Rxf3+ 39.Rxf3 Qxf3+
40.Ke1 Qe4+ 41.Kf1 Qf3+ (3.815.724) 543

12.02 0:12 +0.20++ 31...Bxd5 32.Rxd5 e3 33.Kf1 exf2
34.Rd1 Re8 35.Kxf2 Qe3+ 36.Kf1 f3
37.a8Q Qe2+ (6.853.568) 565

13.01 0:27 +0.52 31...Bxd5 32.Rxd5 e3 33.Rd1 Ra8
34.Qc4+ Kh8 35.Qxf4 exf2+ 36.Qxf2 Rxa7
37.Re1 Qd7 38.Qe2 Bf6 39.Rf1 Qc6
40.Qe3 (15.670.876) 577

14.01 2:15 0.00 31...Bxd5 32.Rxd5 e3 33.Kf1 Qe4
34.a8Q Qb1+ 35.Ke2 Qxb2+ 36.Kf3 Qxf2+
37.Ke4 Qxg2+ 38.Kd3 Qd2+ 39.Ke4 Qc2+
40.Kf3 Qf2+ 41.Ke4 Qc2+ (83.789.561) 616

15.01 3:27 0.00 31...Bxd5 32.Rxd5 e3 33.Kf1 Qe4
34.a8Q Qb1+ 35.Ke2 Qxb2+ 36.Kf3 Qxf2+
37.Ke4 Qxg2+ 38.Kd3 Qd2+ 39.Ke4 Qc2+
40.Kf3 Qf2+ 41.Ke4 Qc2+ (127.708.990) 614

16.01 5:27 +0.52++ 31...Bxd5 32.Rxd5 e3 33.Kf1 exf2
34.Rd1 Re8 35.Kxf2 Qe3+ 36.Kf1 f3
37.Ra1 f2 38.g3 Qe1+ 39.Kg2 Ra8
40.Qb5 Qe4+ 41.Kxf2 Rf8+ 42.Kg1 Bh6 (198.786.968) 606

17.01 6:38 +0.32 31...Bxd5 32.Rxd5 e3 33.Kf1 exf2
34.Rd1 Re8 35.Kxf2 Qe3+ 36.Kf1 f3
37.Ra1 f2 38.g3 Qe1+ 39.Kg2 Ra8
40.Qb5 Qe4+ 41.Kh3 Rf8 42.Qa6 Qa8
43.Rf1 Rf7 44.Qa2 Qxa7 (242.861.370) 608

18.01 13:05 +0.16 31...Bxd5 32.Rxd5 e3 33.Kf1 exf2
34.Rd1 Re8 35.Kxf2 Qe3+ 36.Kf1 f3
37.Ra1 f2 38.g3 Qe1+ 39.Kg2 Ra8
40.Qb5 Qe4+ 41.Kf1 Rf8 42.a8Q Rxa8
43.Qb3+ Kh8 44.Rxa8+ Qxa8 (476.350.224) 606

19.01 44:13 +0.96 31...Bxd5 32.Rxd5 e3 33.Rd1 exf2+
34.Kxf2 Ra8 35.Qa2+ Kh8 36.Re1 Qd7
37.Qa6 Rxa7 38.Qe6 Bf8 39.Qxd7 Rxd7
40.Re4 Rb7 41.b4 Rc7 42.Rxf4 Bd6
43.Rf3 Be5 44.b5 Bxc3 (1.632.035.884) 614

20.01 87:24 +1.21 31...Bxd5 32.Rxd5 e3 33.Rd1 exf2+
34.Kxf2 Ra8 35.Qa2+ Kh8 36.Re1 Qc5+
37.Kf1 Bf8 38.Qf7 Qxa7 39.Qxa7 Rxa7
40.Kf2 Kg7 41.Kf3 Rb7 42.Re2 Bd6
43.Ke4 Kf6 44.Kd4 Rd7 (3.216.273.250) 613

21.01 112:03 +1.17 31...Bxd5 32.Rxd5 e3 33.Rd1 exf2+
34.Kxf2 Ra8 35.Qa2+ Kh8 36.Re1 Qc5+
37.Kf1 Bf8 38.Qf7 Qxa7 39.Qxa7 Rxa7
40.Kf2 Kg7 41.Kf3 Rb7 42.Re2 Bd6
43.Ke4 Kf6 44.Kd4 Rd7
{[d]8/3r3p/3b1k2/8/3K1p2/2P5/1P2R1PP/8 w - - 0 1
=/+ Slight advantage for Black} (4.129.880.636) 614

best move: Ba8xd5 time: 124:13.609 min n/s: 614.590 nodes: 4.580.910.590

Eelco

[yanquis1972]

i narrowed the tree to 10% & extended the depth while letting it more or less auto-run during the INSANE bosna icc blitz qualifier between cheparinov and palinin (i hope someone else got to witness that; screw hockey) -- here's my final IDeA result (tree available upon request i suppose)




engine rybka 3 human

i'm going to let r3 human run in mpv-2 for a good while as well, to see if it produces similar results. still trying to get the hang of IDeA vs 'normal' engine analysis.

[zullil]

Here is a position from their sicilian match:

[d]b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - - 0 1

Stockfish-1.6.3 (8 threads) prefers Bxd5, at least to depth 27:

Code: Select all

Searching: b4rk1/P3q1bp/Q7/3R4/4pp2/2P5/1P3PPP/3R2K1 b - -
infinite: 0 ponder: 0 time: 0 increment: 0 moves to go: 0
 2     -0.81   00:01      763 Bxd5 Rxd5 Ra8 
 3     -0.36   00:01     2068 Bxd5 Rxd5 Ra8 Ra5 
 4     -0.48   00:01     3142 Bxd5 Rxd5 Ra8 Ra5 Bf6 Qc4+ Kf8 
 5     -0.48   00:01     4901 Bxd5 Rxd5 Ra8 Ra5 Qf7 Ra4 
 6     -0.44   00:01    17942 Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Qf7 Qc5 
 7  >  -0.24   00:01    25447 Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Qf7 Qc5 e2 
 8     +0.00   00:01    65833 Bxd5 Rxd5 Ra8 Ra5 e3 Qb5 exf2+ Kxf2 Qe3+ Kf1 Qc1+ 
                              Ke2 Qe3+ Kf1 
 9     +0.00   00:01   149366 Bxd5 Rxd5 Ra8 Ra5 e3 Qb5 exf2+ Kxf2 Qe3+ Kf1 Qc1+ 
                              Ke2 Qe3+ Kf1 
10     +0.00   00:01   304385 Bxd5 Rxd5 Ra8 Ra5 e3 Qb5 exf2+ Kxf2 Qe3+ Kf1 Qc1+ 
                              Ke2 Qe3+ Kf1 
11  <  -0.20   00:01   981545 Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Kh8 Kf1 exf2 Qe2 
12     -0.24   00:01    1640k Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Kh8 Kf1 h6 Qa6 exf2 Ra1 
                              Bf6 Qb6 Kg7 Qxf2 Kf7 
13     +0.40   00:01    4615k Bxd5 Rxd5 Ra8 Ra5 e3 Kf1 Qe4 Ra1 f3 g3 e2+ Ke1 
                              Kf7 Qd6 Bf6 Qb8 Kg6 h4 Kf7 h5 
14     +0.44   00:04   25471k Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Kh8 Kf1 h6 fxe3 fxe3 
                              Qc6 Qd8 Qd5 Qxd5 Rxd5 Rxa7 Ke2 Rb7 Rd8+ Kh7 
15     +0.65   00:05   32218k Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Kh8 Kf1 h6 Qd5 Rxa7 
                              Rxa7 Qxa7 Qd8+ Kh7 Qd3+ Kg8 Qd5+ Kf8 Qd6+ Ke8 
                              Qe6+ Qe7 Qc8+ Kf7 Qc4+ Kg6 Qxf4 exf2 Qg3+ Kf7 
                              Qf4+ Qf6 Qxf6+ Bxf6 Kxf2 
16     +0.48   00:07   52473k Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Kh8 Kf1 h6 Qd5 Rxa7 
                              Rxa7 Qxa7 Qd8+ Kh7 Qd3+ Kg8 Qd5+ Kf8 Qd6+ Ke8 
                              Qe6+ Qe7 Qxe7+ Kxe7 fxe3 fxe3 Ke2 Be5 g3 h5 Kxe3 
                              Kd7 Kd3 Kc6 Ke4 
17     +0.48   00:09   66065k Bxd5 Rxd5 Ra8 Ra5 e3 Qc4+ Kh8 Kf1 h6 Qd5 Rxa7 
                              Rxa7 Qxa7 Qd8+ Kh7 Qd3+ Kg8 Qd5+ Kf8 Qd6+ Ke8 
                              Qe6+ Qe7 Qxe7+ Kxe7 fxe3 fxe3 Ke2 Be5 g3 h5 Kxe3 
                              Kd7 Kd3 Kc6 Ke4 
18  >  +0.69   00:12   94962k Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qd7 
                              Ra1 Bf8 b4 Bg7 
19     +1.05   00:19  158990k Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qd7 
                              Ra1 Qd2+ Kf1 Qd3+ Kg1 f3 gxf3 Be5 Kf2 Bd6 Qf7 
                              Qd2+ Kf1 Qxb2 Ra2 
20     +1.21   00:55  493225k Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qc5+ 
                              Kf1 Bf8 Qa4 Qxa7 Qc6 Qa2 b4 Ra6 Qf3 Rg6 Qe2 Qb3 
                              Qd2 Kg7 Re4 Rd6 Qe1 
21     +1.37   01:56    1026M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qc5+ 
                              Kf1 Bf8 Qa4 Qxa7 Qc6 Qa2 b4 Ra6 Qf3 Rg6 Re8 Kg7 
                              Re1 Qc4+ Kg1 Qc6 Re4 Bd6 Kh1 Kf7 Kg1 Be5 c4 Bd4+ 
22     +1.37   03:05    1629M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qc5+ 
                              Kf1 Bf8 Qa4 Qxa7 Qc6 Qa2 b4 Ra6 Qf3 Rg6 Rd1 Qc4+ 
                              Qd3 Qc6 Qf3 Qb5+ Kg1 Qe5 Kf1 Re6 g3 Bd6 gxf4 Qxf4 
                              Qxf4 Bxf4 
23     +1.41   05:39    2978M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qc5+ 
                              Kf1 Bf8 Qa4 Qxa7 Qc6 Qa2 b4 Ra6 Qf3 Qb3 Kg1 Ra2 
                              Qc6 Qg8 Rf1 Qg5 Qe4 Bd6 Rf2 Ra3 Qe8+ Kg7 Qd7+ Qe7 
                              Qg4+ Kf7 Qf5+ Kg7 
24     +1.37   10:04    5285M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qc5+ 
                              Kf1 Bf8 Qa4 Qxa7 Qc6 Qa2 b4 Ra6 Qf3 Qb3 Kg1 Ra2 
                              Qc6 Qg8 Rf1 Qg5 Qe4 Bd6 Rf2 Ra3 Qe8+ Kg7 Qd7+ Qe7 
                              Qg4+ Kf7 Qf5+ Kg8 
25     +1.49   30:02   15554M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa2+ Kh8 Re1 Qc5+ 
                              Kf1 Bf8 Qa4 Qxa7 Qc6 Qa2 b4 Ra6 Qf3 Qb3 Kg1 Ra2 
                              Qc6 Qg8 Rf1 Qg5 Qe4 Bd6 Rf2 Ra3 Qe8+ Kg7 Qd7+ Qe7 
                              Qg4+ Kh6 Qh3+ Kg5 g3 fxg3 hxg3 Rxc3 
26     +1.37 1:22:01   42537M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa4 Rxa7 Qb3+ Qf7 
                              Rd8+ Bf8 Rb8 Rd7 Qxf7+ Kxf7 Kf3 Bd6 Rb5 Ke6 Rh5 
                              Rb7 Ke4 Rg7 Kf3 Be5 Ke4 Bb8 Rh6+ Kd7 Kf3 Re7 c4 
                              Bd6 Kg4 Bc5 b3 Bd6 
27     +1.33 2:13:10   69256M Bxd5 Rxd5 e3 Rd1 exf2+ Kxf2 Ra8 Qa4 Rxa7 Qb3+ Qf7 
                              Rd8+ Bf8 Rb8 Rd7 Qxf7+ Kxf7 Kf3 Bd6 Rb5 Ke6 Rh5 
                              Rb7 Ke4 Rg7 Kf3 Be5 Ke4 Bb8 Rh6+ Kd7 Kf3 Re7 c4 
                              Bd6 Kg4 Kc6 b4 Re2 Kf3 Re3+ Kg4 
Nodes: 72712517390
Nodes/second: 8654513
Best move: Bxd5
Ponder move: Rxd5

[yanquis1972]

as i suspected the possible variations are so complex that rybka has yet to reach depth 20 in mpv 2 after over 2 hours, however the sample search is currently giving -1.14 for e3; i remain skeptical that that will hold. i'll let it run to d20 for each move and post the results. (and as i typed this, the SS dropped to -.98). for some reason i see d21 as a magical # as far as rybka is concerned, but i want to free up my machine at some point & that may require going overnight for all i know.

[yanquis1972]

1. [-0.75] d=20 1...Bxd5 2.Rxd5 e3 3.Rd1 exf2 4.Kxf2 Ra8 5.Qa2 Kh8 6.Re1 Qc5 7.Kf1 Bf8 8.Qa4 Qxa7 9.Qc6 Qb8 10.Rd1 Bg7 11.b4 Qg8 12.b5 Rc8 13.Qe4 Qb3 14.Qd5 Qxd5 15.Rxd5 Bxc3 16.b6 Rb8 (3:31:48) 5285056kN
2. [-0.68] d=20 1...e3 2.Qd6 exf2 3.Kf1 (3:01:32) 4818536kN

so both IA & IDeA are roughly in concurrence about both evaluation & move ordering.

[Marc MP]

StockFish & IvanHoe both initially saw a perpetual check after 1... e3 2.Qc4 Kh8 3.Qc5 Qf6 4.Rg5 ef2+ 5.Kf2 f3 6.g3:

[d]b4r1k/P5bp/5q2/2Q3R1/8/2P2pP1/1P3K1P/3R4 b - - 0 1

6...Qe6 7.Re1 Qb3 8.Rxg7 Qxb2+ 9.Ke3 Kxg7 10.Qg5+ Kf7 11.Qf4+ Kg8 12.Qg4+ Kh8 13.Qd4+ Kg8 14.Qg4+

But when I start back Stockfish from the last diagram, it finds attacking continuations for black:

Code: Select all

	0,00	16	12992393	Qe6 Re1 Qb3 Rxg7 Qxb2+ Ke3 Kxg7 Qg5+ Kh8 Qe5+ Kg8 Qg5+ Kf7 Qf4+ Kg8 Qg5+ 

        0,20	16	18590864	Qh6 h4 Qe6 Qe3 Qh3 Rd2 Qg2+ Ke1 f2+ Rxf2 Qh1+ Ke2 Rd8 Rf1 Qb7 b4 Qa6+ b5 Qa2+ Ke1 Qc2 

	0,08	17	27711696	Qh6 h4 Qe6 Re1 Qd7 Qe3 Bf6 Rh5 Bb7 b4 Qh3 Qd3 Qg2+ Ke3 Rf7 Rf5 Kg7 Rxf6 Rxf6 Qd7+ Rf7 Qg4+ Kh8 a8R+ Bxa8 Qc8+ Kg7 Qxa8 Qxg3 

	0,80	18	76088648	Qh6 h4 Qe6 Re1 Qd7 Qe3 Bf6 g4 Qa4 Kf1 Bxg5 Qxg5 Qa6+ Kf2 Qxa7+ Re3 Qb8 Qe5+ Qxe5 Rxe5 Rd8 Re7 Rd2+ Ke1 f2+ Kf1 Bd5 Re2 Rxe2 Kxe2 

	0,84	19	138358560	Qh6 h4 Qe6 Qe3 Qh3 Rd2 Qg2+ Ke1 f2+ Rxf2 Qh1+ Ke2 Rd8 Rf1 Qb7 Rc1 Qg2+ Ke1 Rf8 Qe2 Qg1+ Kd2 Qxa7 Rf1 Rd8+ Ke1 Qa1+ Kf2 Rf8+ Kg1 Rxf1+ Qxf1 

	1,05	20	209788653	Qh6 Rh5 Qg6 Qg5 Qf7 Rh4 Qxa7+ Qe3 Qb8 Qd2 Bc6 Re1 Bf6 Rd4 Qb5 h4 Kg8 Rd3 Bg7 Re7 Qb6+ Kf1 

	0,60	21	336181761	Qh6 Rh5 Qg6 Qg5 Qf7 Rh4 Qxa7+ Qe3 Qb8 Rd2 Re8 Qc5 Bf8 Qd4+ Bg7 Qc5 

So maybe whether 1... e3 or 1...Bxd5 is best, will depend on king safety evaluation?