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Up Topic The Rybka Lounge / Test Positions / Wei Yi-Bruzon Batista, 6th Hainan Danzou 2015
- - By kevsamiga (*) [gb] Date 2015-09-24 06:35 Edited 2015-09-24 06:46
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - 0 21


21. Nd5 is a strong novelty here with from the exchange of knights leads to an immediate rook sacrifice on f7
in morphy style to drag out the king, and a persuant king hunt ending 15 moves later with 3 quiet queen moves thereafter
interspaced between.

This game is dubbed the chinese immortal. Wei Yi is 16 years old and rated 2724.

Only Houdini 4 x64 found this move for me in any reasonable length of time. I was curious to know as to what else does.

Latest Stockfish dev 19/09/15 or Komodo 9 or anything else for that matter fails to see the devastating
potential hidden behind the move. But when shown Nd5 stepped forwards and backwards in analysis,
they then prefer the move but never find it on their own accord, why ?

Full game:

1. e4 c5 2. Nf3 e6 3. Nc3 a6 4. Be2 Nc6 5. d4 cxd4 6. Nxd4 Qc7 7. O-O Nf6 8.
Be3 Be7 9. f4 d6 10. Kh1 O-O 11. Qe1 Nxd4 12. Bxd4 b5 13. Qg3 Bb7 14. a3 Rad8
15. Rae1 Rd7 16. Bd3 Qd8 17. Qh3 g6 18. f5 e5 19. Be3 Re8 20. fxg6 hxg6 21. Nd5
Nxd5 22. Rxf7 Kxf7 23. Qh7+ Ke6 24. exd5+ Kxd5 25. Be4+ Kxe4 26. Qf7 Bf6 27.
Bd2+ Kd4 28. Be3+ Ke4 29. Qb3 Kf5 30. Rf1+ Kg4 31. Qd3 Bxg2+ 32. Kxg2 Qa8+ 33.
Kg1 Bg5 34. Qe2+ Kh4 35. Bf2+ Kh3 36. Be1 1-0
Parent - By user923005 (****) [us] Date 2015-09-24 07:23
I stared at a double rainbow.
Until my brain imploded.  I tend to think inverted.
There is no way to put it back.

Nice position, BTW.
I can't wait to give it a pounding with a few engines.
However, due to TCEC, I have all my machines working overtime on various projects right now.
But I will get to it.
Parent - By user923005 (****) [us] Date 2015-09-25 04:56
I have a list of 27 engines lined up to try it, at 1/2 hour each.
So far, standard, bleeding edge Stockfish failed to find it after 1/2 hour, but Sting found it right away:

FEN:
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - 0 1


Sting-sf-5-x64-avx:
   2  00:00         2,297  8,203  +1.81  Qh6 Bf8
   3  00:00         3,040  10,818  +1.29  Qh6 Bf8 Qh3
   4  00:00         5,561  19,650  +1.25  a4 b4 Nd5 Nxd5 exd5 Bxd5
   5  00:00         6,186  21,781  +1.25  a4 b4 Nd5 Nxd5 exd5 Bxd5
   6-  00:00         6,957  24,410  +1.16  a4
   6-  00:00         7,427  25,968  +1.08  a4
   6+  00:00        11,790  40,515  +1.36  Rf2
   6+  00:00        12,960  44,383  +1.81  Rf2
   6  00:00        14,176  48,382  +1.41  Rf2 Nh5 g4 Nf4 Bxf4 exf4 Rxf4
   7-  00:00        17,843  59,875  +1.27  Rf2
   7-  00:00        19,516  65,053  +1.17  Rf2
   7  00:00        23,039  75,786  +1.13  Re2 Nh5 g4 Nf4 Bxf4 exf4 Rxf4
   8+  00:00        26,379  74,940  +1.25  Re2
   8+  00:00        26,938  75,245  +1.37  Re2
   8+  00:00        27,987  76,676  +1.56  Re2
   8  00:00        33,270  89,195  +1.57  Re2 d5 exd5 Nxd5 Nxd5 Bxd5 Qh6 Bf6
   9+  00:00        42,492  110,656  +1.69  Rf2
   9+  00:00        44,110  112,813  +1.81  Rf2
   9-  00:00        67,578  160,137  +1.45  Rf2
   9  00:00        72,049  167,167  +1.77  Rf2 Nh5 Ref1 Nf4 Bxf4 exf4 Rxf4 Bg5 R4f2 Bc6 Nd5 Bh4
  10-  00:00       100,790  201,983  +1.65  Rf2
  10-  00:00       107,377  206,494  +1.53  Rf2
  10  00:00       116,736  219,428  +1.65  Rf2 Nh5 Ref1 Nf4 Bxf4 exf4 Rxf4 Bg5 R4f2 f6 Nd5 Bxd5 exd5 f5 Bxf5 gxf5 Qxf5
  11-  00:00       179,363  312,479  +1.53  Rf2
  11-  00:00       199,258  327,188  +1.41  Rf2
  11  00:00       236,823  375,313  +1.49  Rf2 Bc8 Qf3 Kh8 Rff1 Rb7 Bg5 Nh5 Bxe7 Rexe7 a4 bxa4 Nd5
  12-  00:00       585,922  745,447  +1.37  Rf2
  12-  00:00       805,111  833,448  +1.25  Rf2
  12  00:01       940,826  920,573  +1.37  Qf3 Kh8 Kg1 Qc8 Nd5 Bxd5 exd5 Rc7 c3 Rb7 a4 Kg8 axb5 axb5
  13-  00:01     1,269,448  1,129,402  +1.25  Qf3
  13  00:01     1,529,427  1,262,945  +1.45  Qf3 Kh8 Re2 d5 exd5 Bxd5 Qh3+ Kg8 Nxd5 Nxd5 Bd2 Bf8 g4 Nf4 Bxf4 exf4 Rxe8 Qxe8 Rxf4
  14+  00:01     1,648,392  1,305,140  +1.57  Qf3
  14  00:01     1,737,680  1,298,714  +1.49  Qf3 Kh8 Re2 d5 exd5 Bxd5 Qh3+ Kg8 Nxd5 Rxd5 Ref2 e4 Be2 Qc8 Qh6 Rf5 Rxf5 gxf5 Qg5+ Kf8 Rxf5 Qxc2 Qh6+
  15-  00:01     2,064,574  1,410,228  +1.41  Qf3
  15-  00:01     2,243,477  1,430,788  +1.33  Qf3
  15-  00:02     4,972,540  2,212,968  +1.03  Qf3
  15  00:03    11,088,649  3,413,992  +0.96  Bh6 Qc8 Qf3 Kh8 Bg5 Nh5 Be3 Bh4 g3 Bf6 a4 b4 Nd5 Bxd5 exd5 e4 Bxe4 Bxb2
  16+  00:03    13,477,046  3,489,654  +1.09  a4
  16+  00:03    13,867,292  3,512,485  +1.21  a4
  16+  00:04    15,300,461  3,583,246  +1.66  a4
  16  00:04    18,094,977  3,804,662  +1.29  a4 bxa4 Bc4 d5 exd5 a3 bxa3 Qc7 Bg5 Nh5 Bh6 Nf6 Bb3 Nxd5 Rxe5 Qxe5 Qxd7
  17+  00:04    18,661,637  3,783,019  +1.41  a4
  17+  00:04    18,772,916  3,774,209  +1.53  a4
  17-  00:05    20,175,836  3,832,067  +1.17  a4
  17  00:05    22,185,648  3,942,012  +1.25  a4 bxa4 Bc4 d5 exd5 Qc8 Bg5 Nh5 Bxe7 Rdxe7 Qxc8 Rxc8 b3 axb3 cxb3 Rd8 g4 Ng7 Rf6 Kf8 Kg2 Ne8 Rb6 f6
  18  00:06    24,051,699  3,931,943  +1.25  a4 bxa4 Bc4 d5 exd5 Qc8 Bg5 Nh5 Bxe7 Rdxe7 Qxc8 Rxc8 b3 axb3 cxb3 Rd8 g4 Ng7 Rf6 Kf8 Kg2 Ne8 Rb6 f6
  19-  00:08    29,750,985  3,628,611  +1.17  a4
  19+  00:08    31,897,128  3,738,967  +1.33  a4
  19+  00:08    32,787,102  3,782,981  +1.45  a4
  19  00:10    38,921,032  3,861,979  +1.45  Re2 d5 exd5 Bxd5 Nxd5 Rxd5 Ref2 Qc8 Bf5 Qd8 Bg4 Rf8 Bf3 Rd6 Bh6 Qd7 Qxd7 Nxd7 Bxf8 Kxf8 c4 f5 Bd5 Bh4
  20-  00:11    44,932,704  3,913,316  +1.33  Re2
  20-  00:11    47,158,339  3,961,221  +1.21  Re2
  20  00:12    48,181,894  3,972,126  +1.21  Re2 d5 exd5 Bxd5 Nxd5 Rxd5 Ref2 Qc8 Bf5 Qd8 Bg4 Rd6 Be2 Rf8 c4 Ne4 Rf3 Ng5 Bxg5 Bxg5 cxb5 e4
  21+  00:13    54,324,312  4,179,114  +1.33  Qf3
  21+  00:13    58,309,134  4,308,026  +1.45  Qf3
  21-  00:15    69,815,784  4,605,566  +1.09  Qf3
  21  00:15    70,895,255  4,596,722  +1.09  Qf3 d5 exd5 Bxd5 Nxd5 Rxd5 Bf2 Rf8 Bg3 Qd6 Bh4 e4 Bxe4 Nxe4 Bxe7 Qxe7 Rxe4 Qc7 Qe2 Rh5 h3 Qc6 Kg1 Rc5 c3 f5
  22-  00:21   106,152,292  5,031,629  +0.96  Qf3
  22+  00:22   115,382,292  5,115,597  +1.21  Nd5
  22+  00:23   121,676,680  5,215,459  +1.39  Nd5
  22  00:29   172,978,680  5,799,399  +1.45  Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qc8 g5 Nh5 a4 Rf8 axb5 axb5 Rb1 f5 gxf6 Rxf6 Qg2 Qg8 Rxf6 Bxf6 Rf1 Nf4 Bxf4 exf4 Rxf4 Bxb2 Bxg6
  23-  00:31   185,389,594  5,855,271  +1.33  Nd5
  23  00:32   190,497,640  5,866,520  +1.37  Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qc8 g5 Nh5 a4 Rf8 axb5 axb5 Ra1 Qd8 Qg2 Kg8 Qg4 b4 Ra6 b3 c3 Rc7 Rc6 Rb7 Qf3 Nf4 Bxf4 exf4 Qxf4 Bxg5 Qxd6 Qxd6 Rxd6 Ra8
  24-  00:39   245,324,720  6,206,352  +1.25  Nd5
  24  00:40   249,970,028  6,199,653  +1.33  Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qc8 g5 Nh5 a4 Rf8 axb5 axb5 Ra1 Kg8 Kg1 Qd8 h4 Qc8 c3 Ng7 Rf2 Nh5 Raf1 Qe8 Qg4 Rb8 b3 Qc8 Qxc8
  25-  00:44   277,603,095  6,249,647  +1.25  Nd5
  25  00:46   291,756,446  6,300,074  +1.33  Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qc8 g5 Nh5 a4 Rf8 axb5 axb5 Ra1 Kg8 Kg1 Qd8 h4 Qc8 c3 Ng7 Rf2 Nh5 Raf1 Qe8 Qg4 Rb8 b3 Qc8
  26+  00:53   349,795,008  6,485,010  +1.41  Nd5
  26  00:58   384,791,411  6,533,293  +1.33  Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qc8 g5 Nh5 Rf2 Rf8 Ref1 Kg8 Qe4 Qe8 c3 Rc7 Kg2 Kh8 Kg1 f5 gxf6 Rxf6 Qg4 Rxf2 Rxf2 Nf6 Qh3+ Nh5
  27+  01:10   477,744,609  6,823,655  +1.41  Nd5
  27-  01:27   608,413,114  6,934,905  +1.25  Nd5
  27  01:38   684,452,414  6,977,159  +1.45  Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qc8 g5 Nh5 Re2 Bd8 a4 Ba5 Ref2 Ree7 Qg2 Kg8 axb5 axb5 Qe4 Qh3 Rf3
Parent - By user923005 (****) [us] Date 2015-09-25 05:57
Komodo found it in about 3 minutes:

FEN:
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - 0 1


Komodo-9.02-64bit:
   2  00:00           821  37,315  -0.54  Nd5 Nxd5 exd5 Bxd5
   2  00:00           964  43,814  +0.02  b3 d5
   2  00:00         1,254  54,519  +0.23  g3 Qc7
   2  00:00         1,676  67,037  +0.34  a4 b4
   2  00:00         2,139  82,262  +0.39  Rd1 Rc7
   2  00:00         2,430  93,454  +0.56  Qh6 Bf8
   3  00:00         3,792  140,438  -6.80  Qh6 Bf8 h3 Bxh6
   3  00:00         4,376  162,066  -0.54  Nd5 Nxd5 exd5
   3  00:00         4,721  174,844  +0.10  g3 Rc7 Bb6
   3  00:00         5,378  199,176  +0.22  Ra1 Rc7 Bb6
   3  00:00         6,981  258,544  +0.41  Kg1 Qa8 Bb6
   4  00:00        25,644  884,230  +0.62  Kg1 Bc6 Qh6 Bf8
   5-  00:00        28,553  984,535  +0.51  Kg1 Bc6
   5  00:00        33,077  1,102,471  +0.51  Kg1 Bc6 Rd1 Bf8 Qf3
   6+  00:00        35,677  1,189,130  +0.58  Kg1
   6+  00:00        40,766  1,314,943  +0.66  Kg1
   6-  00:00        43,105  1,390,389  +0.56  Kg1 Qc8
   6-  00:00        46,591  1,455,864  +0.41  Kg1 Qc8
   6  00:00        52,426  1,588,517  +0.49  Kg1 Qc8 Qf3 Qa8 Rd1 Rc7
   7-  00:00        62,228  1,830,057  +0.41  Kg1 Qc8
   7-  00:00        70,837  2,023,752  +0.42  Rd1 Bc6
   7-  00:00        75,789  2,165,226  +0.32  Rd1 Bc6
   7+  00:00        80,074  2,224,117  +0.51  Kg1
   7+  00:00        81,400  2,260,947  +0.61  Kg1
   7  00:00        84,585  2,349,413  +0.68  Kg1 Qc8 Qf3 Bd8 Nd5 Nxd5 exd5
   8-  00:00        90,737  2,452,185  +0.61  Kg1 Qc8
   8-  00:00        97,276  2,559,739  +0.49  Kg1 Qc8
   8-  00:00       108,461  2,780,808  +0.39  Kg1 Qc8
   8  00:00       119,065  2,976,401  +0.26  Kg1 d5 exd5 Bxd5 Nxd5 Rxd5 Qf3 Qd7
   8  00:00       122,170  2,979,574  +0.33  Rd1 d5 exd5 Bxd5 Nxd5 Rxd5 Qf3 Qd7
   9+  00:00       195,620  4,075,085  +0.40  Rd1
   9+  00:00       207,542  4,235,248  +0.47  Rd1
   9  00:00       223,473  4,381,522  +0.41  Rd1 d5 exd5 Bxd5 Nxd5 Rxd5 Qf3 Rd6 g4
   9+  00:00       243,440  4,592,852  +0.57  Qf3
   9+  00:00       250,345  4,635,709  +0.72  Qf3
   9  00:00       281,096  5,019,212  +0.84  Qf3 Kh8 Rd1 d5 exd5 Bxd5 Nxd5 Rxd5 a4 Qd7 axb5
  10-  00:00       386,036  5,676,641  +0.77  Qf3 d5
  10-  00:00       401,540  5,735,933  +0.69  Qf3 d5
  10-  00:00       402,847  5,754,603  +0.70  Nd5 Nxd5
  10-  00:00       430,272  5,893,725  +0.45  Nd5 Nxd5
  10+  00:00       433,184  5,933,612  +0.75  Qf3
  10  00:00       459,433  6,044,701  +0.74  Qf3 d5 exd5 Bxd5 Nxd5 Rxd5 g4 Rxd3 cxd3 Qxd3 Qc6
  11+  00:00       474,244  6,002,701  +0.81  Qf3
  11  00:00       533,523  6,203,351  +0.85  Qf3 Kh8 Rd1 Kg7 a4 b4 Nd5 Bxd5 exd5 Rh8 Kg1 a5
  12+  00:00       615,059  6,473,889  +0.92  Qf3
  12+  00:00       683,066  6,631,290  +0.99  Qf3
  12-  00:00       826,707  6,946,697  +0.92  Qf3 Kh8
  12  00:00       988,656  7,269,085  +0.81  Qf3 Kh8 Rd1 Rf8 Qh3+ Kg8 Bh6 Re8 Qf3 Kh8 Rde1 Rc7 Bg5 Kg7 Be3
  13+  00:00     1,071,440  7,338,177  +0.88  Qf3
  13+  00:00     1,312,442  7,585,909  +0.95  Qf3
  13+  00:00     1,475,775  7,726,105  +1.05  Qf3
  13-  00:00     1,523,354  7,732,294  +0.96  Qf3 Kh8
  13+  00:00     1,593,147  7,809,069  +1.08  Qf3
  13  00:00     1,800,723  7,897,388  +1.16  Qf3 Kg7 Nd5 Bxd5 exd5 Rh8 g4 Qe8 g5 Nh5 c3 Bd8 a4 bxa4 Bxa6 a3 bxa3 f5
  14-  00:00     1,981,268  8,020,844  +1.09  Qf3 d5
  14  00:00     2,773,422  8,776,140  +1.13  Qf3 Kg7 Nd5 Bxd5 exd5 Rh8 g4 Qe8 g5 Nh7 Qg2 Qd8 Rg1 Nf8 a4 Rb7 Ref1 Rh5 c3
  15-  00:00     3,949,865  8,875,602  +1.06  Qf3 d5
  15-  00:00     3,998,655  8,885,384  +0.99  Qf3 Kg7
  15-  00:00     4,201,917  8,883,044  +0.89  Qf3 Kg7
  15+  00:00     4,466,921  8,897,743  +0.97  Qf3
  15  00:00     4,946,932  8,833,310  +1.16  Qf3 d5 exd5 Bxd5 Nxd5 Rxd5 Be4 Rd6 Bc6 Rf8 Bh6 Qc7 Bxf8 Bxf8 Be4 Nxe4 Rxe4 Bg7 Rd1 Rxd1+ Qxd1
  16-  00:00     5,060,291  8,846,164  +1.09  Qf3 Kg7
  16-  00:00     5,893,459  8,861,845  +1.02  Qf3 Kg7
  16-  00:00     6,291,956  8,848,946  +0.92  Qf3 Kg7
  16  00:00     6,917,511  8,868,100  +0.85  Qf3 Kg7 Nd5 Bxd5 exd5 Rf8 a4 bxa4 Ra1 Qa5 Bg5 Nxd5 Bh6+ Kxh6 Qh3+ Kg7 Qxd7 Qc7 Qxc7 Nxc7 Rxa4 f5 Bxa6
  17  00:00     7,800,838  8,864,088  +0.82  Qf3 Kg7 Nd5 Bxd5 exd5 Rf8 a4 bxa4 Ra1 Qa5 Bg5 Nxd5 Bh6+ Kxh6 Qh3+ Kg7 Qxd7 Qc7 Qxc7 Nxc7 Rxa4 f5 Bxa6 Rb8
  18-  00:01    10,161,798  9,048,286  +0.75  Qf3 Kg7
  18+  00:01    15,292,322  9,318,380  +0.82  Qf3
  18-  00:01    17,674,856  9,248,489  +0.75  Qf3 Kg7
  18-  00:02    20,556,991  9,255,216  +0.60  Qf3 Kg7
  18  00:03    28,727,894  9,390,742  +0.50  Qf3 Kg7 Nd5 Bxd5 exd5 Rf8 g4 Nh7 a4 bxa4 Ra1 Bg5 Rxa4 Bxe3 Qxe3 Qh4 b3 Qg5 Qxg5 Nxg5 Rxa6 e4 Bb5 Rdd8
  18+  00:03    35,914,306  9,393,746  +0.71  g4
  18  00:04    38,411,923  9,423,398  +0.58  g4 d5 g5 Nh5 exd5 Bf8 Qf3 Nf4 Be4 Bd6 Qg4 Rc7 Rd1 Qc8 Rg1 Qxg4 Rxg4 Bxa3 Nxb5 axb5 bxa3 Rc4
  19-  00:04    42,532,541  9,491,220  +0.51  g4 d5
  19-  00:05    53,786,337  9,524,230  +0.44  g4 d5
  19+  00:06    65,842,040  9,572,311  +0.58  Qf3
  19-  00:08    86,388,532  9,614,212  +0.51  Qf3 Kg7
  19  00:10    96,257,527  9,612,717  +0.52  Qf3 Kg7 Nd5 Bxd5 exd5 Rf8 c4 bxc4 Bxc4 Nh7 Bxa6 Bg5 Rc1 Bxe3 Qxe3 f5 Bc8 Rc7 Rxc7+ Qxc7 Rc1 Qb8 Be6 Qxb2 Rc7+ Kh8 Qh6 Qa1+ Rc1 Qxa3
  20+  00:11   113,538,870  9,659,875  +0.59  Qf3
  20-  00:12   118,769,621  9,684,659  +0.52  Qf3 Kg7
  20+  00:13   132,847,808  9,703,461  +0.66  a4
  20+  00:18   178,032,759  9,681,466  +0.91  a4
  20  00:18   183,789,156  9,707,827  +0.90  a4 d5 exd5 Bxd5 axb5 e4 Be2 Be6 Qg3 Nd5 Nxd5 Rxd5 c4 Rd7 Ra1 axb5 c5 Rd3 Bxd3 Qxd3 c6 Rc8 Rfd1 Qe2 c7 Qxb2 Bh6
  21-  00:19   193,898,452  9,740,648  +0.83  a4 d5
  21  00:22   220,616,220  9,817,270  +0.87  a4 d5 exd5 Bxd5 axb5 e4 Be2 Be6 Qg3 Nd5 Nxd5 Rxd5 c4 Rd7 Qf4 axb5 c5 Qb8 Qxe4 Bd5 Qg4 Qb7 b4 Bf8 Bf3 Bg7 Bf4 Rdd8 Rxe8+ Rxe8 Rd1 Bxf3
  22+  00:35   354,610,771  10,100,292  +0.94  a4
  22-  00:35   355,848,122  10,101,582  +0.87  a4 d5
  22-  00:35   356,128,246  10,102,364  +0.77  a4 d5
  22  00:35   358,860,967  10,121,595  +0.75  a4 d5 exd5 Bxd5 axb5 e4 Nxd5 Rxd5 Bc4 Rh5 Qg3 Nd5 Qf2 Rf5 Qe2 Nxe3 Qxe3 axb5 Rxf5 gxf5 Bxb5 Bg5 Qg3 f4 Qg4 Re5 Bc4 Qd2 Rf1 Qxc2 b3 Qd2 Qh5
  23+  00:39   401,394,855  10,132,852  +0.82  a4
  23  00:40   414,809,527  10,157,121  +0.87  a4 d5 exd5 Bxd5 axb5 e4 Nxd5 Rxd5 Bc4 Rh5 Qg3 Nd5 Qf2 Rf5 Qg1 Nxe3 Qxe3 axb5 Rxf5 gxf5 Bxb5 Bg5 Qg3 f4 Qg4 Re5 Bc4 Qf6 Ra1 f3 gxf3 exf3 Rf1 f2
  24  00:45   466,113,609  10,224,806  +0.87  a4 d5 exd5 Bxd5 axb5 e4 Nxd5 Rxd5 Bc4 Rh5 Qg3 Nd5 Qf2 Rf5 Qg1 Nxe3 Qxe3 axb5 Rxf5 gxf5 Bxb5 Bg5 Qg3 f4 Qg4 Re5 Bc4 Qf6 Ra1 f3 gxf3 exf3 Rf1 f2 h4
  25-  01:19   811,863,828  10,246,222  +0.80  a4 bxa4
  25+  01:27   899,696,154  10,236,276  +0.87  a4
  25+  01:41  1,035,806,662  10,228,001  +0.97  a4
  25  02:34  1,583,662,922  10,281,816  +0.92  a4 Bc6 axb5 axb5 Qf3 d5 exd5 Bxd5 Nxd5 Rxd5 Be4 Rd6 Bc6 e4 Bxe4 Nxe4 Qxf7+ Kh8 Rf3 Bh4 Rh3 Re5 g3 Rh5 Rxh4 Nxg3+ hxg3 Rxh4+ gxh4 Qxh4+ Kg2 Qxe1 Qf8+ Kh7 Qe7+ Kg8 Qxd6 Qxe3 Qxg6+ Kf8 Qg3 Qe6 c3 Kf7
  26+  03:09  1,950,570,554  10,320,612  +0.99  a4
  26-  03:10  1,964,503,305  10,324,025  +0.92  a4 d5
  26  03:23  2,107,843,356  10,346,341  +0.96  Nd5 Bxd5 exd5 Rb7 Qf3 Kg7 g4 Rf8 g5 Nh7 h4 Nxg5 hxg5 Bxg5 Kg2 f5 Rh1 Qf6 Qh3 Kg8 c3 Bxe3 Qxe3 Rff7 Reg1 Rh7 Bc2 e4 Qg3 g5 Rf1 Qg6 Qe3 Rh4 Rh3
  27-  03:30  2,182,040,594  10,367,576  +0.89  Nd5 Bxd5
  27+  04:08  2,595,753,157  10,448,887  +0.96  Nd5
  27-  04:15  2,669,815,406  10,443,314  +0.89  Nd5 Bxd5
  27  04:27  2,789,953,067  10,446,996  +0.86  Nd5 Bxd5 exd5 Rb7 Qf3 Kg7 g4 Rf8 g5 Nh7 h4 Nxg5 hxg5 Bxg5 Kg2 f5 Rh1 Qf6 Qh3 Kg8 Bxg5 Qxg5+ Kf1 Re7 Qh8+ Kf7 Qh7+ Ke8 Qh4 Qxh4 Rxh4 Kf7 Be2 Kg7 Kf2 e4 Reh1 Kf6 Rh7 Rxh7 Rxh7
  28+  04:50  3,049,754,548  10,482,084  +0.93  Nd5
  28-  05:00  3,146,501,461  10,484,956  +0.86  Nd5 Bxd5
  28+  05:47  3,649,975,972  10,507,749  +0.93  Nd5
  28  06:03  3,818,939,959  10,509,861  +1.01  Nd5 Bxd5 exd5 Rb7 Qf3 Kg7 g4 Rf8 g5 Nh7 h4 Nxg5 hxg5 Bxg5 Kg2 f5 Rh1 Qf6 Qh3 Kg8 Bxg5 Qxg5+ Kf2 Rg7 Qh6 Qxh6 Rxh6 e4 Be2 Rc8 c3 Kf7 Ke3 Kf6 a4 bxa4 Bxa6 Rb8 Rh2
Parent - - By user923005 (****) [us] Date 2015-09-25 18:48
Here are the raw EPD records from 27 engines, and the analysis will be attached in a moment:

3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 38/60;
acs 1412 ; acn 9189889479; ce 89 ; bm a4; pv a4 bxa4 Bc4 a3 b3 Rc7 Bb6 Kg7 Nd5 Bxd5 Bxd5 Qc8 Bxc7 Qxc7 c4 Qc5 b4 Qxb4 Rb1 Qc5 Ra1 Nxd5 cxd5 Qc4 Qd7 Qb5 Qxb5 axb5 Rxa3 Rc8 Ra7 Kf8 Rb7 Rc4 Rb8+ Kg7 Re1 b4 Rb7 Kf8 g3 Bg5 Kg2 Rc2+ Kf3 Rxh2 Rb8+ Ke7 Rxb4;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 36/54+;
acs 1659 ; acn 10851137346; ce 91 ; bm a4; pv a4;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 35/53;
acs 773 ; acn 5054108807; ce 90 ; bm a4; pv a4 bxa4 Bc4 Qc8 Bg5 Qxc4 Bxf6 Bxf6 Qxd7 Bc6 Qxd6 Be7 Qd2 Rb8 Nd5 Bh4 Qh6 Bxd5 Qxh4 Be6 b3 Qxc2 bxa4 Qxa4 Ra1 Qb5 Rfd1 Qe2 h3 Kg7 Re1 Qb5 Rf1 Kg8 Rfd1 Kg7 Qg5 Rh8 Rd6;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 34;
acs 1383 ; acn 8755242469; ce 109 ; bm Nd5; pv Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Bd2 Bd8 g5 Nh5 Re4 Kg8 Rh4 Nf4 Qg3 Qc8 Bxf4 exf4 Rhxf4 Qc5 Be4 Qd4 c3 Qe5 Qf3 Qg7 h4 Rbe7 Kg2 Ra7 Bd3 Bb6 Re4 Rae7 Rfe1 Rxe4 Rxe4 Re5 Qe2 Qh8 a4 bxa4 Bxa6 Bc5 Rxe5 Qxe5 Qxe5 dxe5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 32/31;
acs 1673 ; acn 7267565257; ce 65 ; bm a4; pv a4 bxa4 Nxa4 d5 exd5 Rxd5 Bc4 Qd7 Qxd7 Rxd7 Nb6 Rd6 Bb3 Bd8 Nc4 Rde6 Rd1 Nd5 Bd2 Kg7 Ra1 Nf4 Bxf4 exf4;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 31;
acs 969 ; acn 8104566028; ce 105 ; bm Qf3; pv Qf3 d5 Nxd5 Bxd5 exd5 Rxd5 Bf2 Rf8 Bh4 e4 Bxe4 Nxe4 Bxe7 Qxe7 Rxe4 Qd6 Ree1 Rh5 h3 Rf5 Qe2 Rxf1+ Rxf1 Qc6 Re1 Rd8 Kg1 Kg7 Qf2 Qd5 Rf1 Qd4 Qxd4+ Rxd4;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 31-;
acs 898 ; acn 9432490535; ce 90 ; bm Nd5; pv Nd5 Bxd5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 30/57;
acs 1680 ; acn 19642413393; ce 60 ; bm a4; pv a4 bxa4 Nxa4 d5 Bb6 Qc8 exd5 Rxd5 Qxc8 Bxc8 Nc3 Rd6 Bc7 Re6 Rxe5 Rc6 Ba5 Be6 Ree1 Ng4 h3 Nf6 Kh2 Nh5 g3 f5 Be2 Bc5 Bf3 Rd6;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 30/45;
acs 1210 ; acn 9080921716; ce 70 ; bm Qf3; pv Qf3 Kg7 Nd5 Bxd5 exd5 Rf8 a4 bxa4 Ra1 Qa5 Bg5 Ng8 Bxe7 Nxe7 Qf6+ Kg8 c4 Qd8 Rxa4 Nc8 Qxd8 Rfxd8 Rxa6 Rb7 Rb1 Nb6 Be2 e4 b3 f5 Kg1 Kg7 b4 Rc8 b5 Nxc4;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 29;
acs 1664 ; acn 28292027447; ce 62 ; bm a4; pv a4 bxa4 Nxa4 d5 Bb6 Qc8 exd5 Rxd5 Qxc8 Rxc8 Nc3 Rd7 Rxe5 Bf8 Bg1 Nd5 Nxd5 Bxd5 Rfe1 a5 Re8 Rdd8 Rxd8 Rxd8 Bb5 Be6 c4 Rd2 b3 Kg7 Ra1 Bf5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 29/83;
acs 1532 ; acn 22382849457; ce 86 ; bm a4; pv a4 bxa4 Bc4 a3 b3 Rc7 Bb6 Kg7 Nd5 Bxd5 Bxd5 Nxd5 exd5 f5 b4 Rh8 Qxa3 Rh4 h3 Qc8 Bxc7 Qxc7 Qxa6 Rxb4 Ra1 Kf7 Ra4 Qb7 Qxb7 Rxb7 g4 f4 Kg2 Rc7 c4 Rb7 Ra6 Rb2+ Rf2 Rb3 Rc6 Ra3 Rf3 Ra2+ Kf1 Ra1+ Kf2 Ra2+ Kg1;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 29/59;
acs 1596 ; acn 20256928857; ce 85 ; bm Nd5; pv Nd5 Bxd5 exd5 Rb7 Qf3 Kg7 Rf2 Rh8 g4 Qe8 Ref1 Bd8 Qg2 Nh7;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 29/58;
acs 1377 ; acn 9487759822; ce 103 ; bm a4; pv a4 bxa4 Nxa4 Kg7 Bh6+ Kg8 Nc3 Qc8 Re3 Rc7 Qxc8 Rexc8 Ref3 d5 exd5 e4 Nxe4 Nxe4 Bxe4 f5 Bd3 Bxd5 Rg3 Kf7 c3 Bc4 Re3 Bxd3 Rxd3 g5 h4 gxh4 Rd5 Rc5 Rfxf5+ Kg6 Be3 Rxd5 Rxd5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 29+;
acs 1677 ; acn 14755639450; ce 117 ; bm a4; pv a4 bxa4 Nxa4 d5 Bb6 Qc8 exd5 e4 Bxe4 Nxe4 Rxe4 Rxd5 Qxc8 Bxc8 Rfe1 Be6 c4 Rd2 b3 Rd3 R4e3 Rxe3 Rxe3 Bg5 Re1 Bd2 Re2;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 28/57+;
acs 1600 ; acn 9514071835; ce 135 ; bm a4; pv a4;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 28+;
acs 1505 ; acn 15054423821; ce 86 ; bm a4; pv a4 bxa4 Nxa4 d5 Bb6 Qc8 exd5 Rxd5 Qxc8 Bxc8 Nc3 Rd7 Rxe5 Rxd3 cxd3 Nd7 Rxe7 Rxe7 Bd4 Bb7 Kg1 f5 h4 Rh7 Rf4 a5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 27;
acs 1644 ; acn 19392979999; ce 52 ; bm Nd5; pv Nd5 Nxd5 Rxf7 Kxf7 Qh7+ Ke6 exd5+ Kxd5 Be4+ Kxe4 c4 Kf5 Qh3+ Kf6 Rf1+ Kg7 Qh6+ Kg8 Qxg6+ Kh8 Rf7 Bxg2+ Kxg2 Qa8+ Kh3;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 27/67;
acs 1675 ; acn 26149887490; ce 71 ; bm a4; pv a4 bxa4 Bc4 a3 b3 Rc7 Bb6 Kg7 Ra1 Qc8 Bxc7 Qxc7 Qd3 a5 Bd5 Ba6 Qxa6 Qxc3 Qc4 Qxc4 bxc4 Rc8 Rxa3 Bd8 Raf3 Rc7 Kg1 Nxd5 cxd5 f6 R1f2 Rc4 Re2 a4 Kf1 Bb6 Ra3 Bc5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 27/35;
acs 1484 ; acn 18561803644; ce 106 ; bm a4; pv a4 bxa4 Bc4 a3 b3 Ba8 Rd1 Bb7 Bg5 Rc7 Ra1 Rf8 Bxf6 Bxf6 Nd5 Bxd5 Bxd5 Bg5 c4 a5 Rxa3 Bd2 Qg3 Kg7 Rf3 Qg5 Qxg5 Bxg5 Rxa5 Bd2 Ra6 Bb4 g4 Bc5 Kg2 Rh8 h3 f6 Kg3 g5 Rf1 Kg6;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 26;
acs 1025 ; acn 7865555281; ce 97 ; bm Qf3; pv Qf3 Kg7 Nd5 Bxd5 exd5 Rh8 g4 Qg8 g5 Nh7 Qh3 Qe8 Qg4 Rc7 Rf3 Qc8 Qg2 Kg8 Rh3 Nf8 Rxh8+ Kxh8 a4 bxa4 Ra1 Nd7 Rxa4 Nc5 Bxc5 Rxc5 b4 Rc3 Rxa6;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 25/71;
acs 1002 ; acn 12799042140; ce 111 ; bm a4; pv a4 bxa4 Bc4 a3 b3 Rc7 Bb6 Kg7 Re3 Rh8 Qg3 d5 Bxd5 Bxd5 Nxd5 Nxd5 exd5 Rh5 Ref3 f6 c4 Qd6 Bxc7 Qxc7 h3 Rg5 Qe1;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 25/68;
acs 1325 ; acn 964448270; ce 118 ; bm a4; pv a4 bxa4 Bc4 Qc8 Ba2 Rc7 Qh4 Nh5 Qf2 Bf6 Rd1 Rd8 Bb6 Rxc3 bxc3 Rd7 Qe3 Bc6 Rfe1 a3 c4 Be7 c5 Nf6 cxd6 Rxd6 Bc5 Rxd1 Rxd1 Bxc5 Qxc5 Nxe4 Qxe5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 24;
acs 1631 ; acn 5729799525; ce 48 ; bm Nd5; pv Nd5 Bxd5 exd5 Rb7 Qf3 Kg7 g4 Rf8 g5 Nd7 h4 Rc7 Rf2 Nc5 Bf1;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 24/81-;
acs 1623 ; acn 21349942732; ce 59 ; bm Qf3; pv Qf3 Kg7;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 24/62;
acs 1050 ; acn 13382020897; ce 82 ; bm Nd5; pv Nd5 Bxd5 exd5 Rb7 Qf3 Kg7 g4 Rf8 g5 Nd7 Qg2 Rc7 b4 Rh8;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 23;
acs 641 ; acn 379058313; ce 83 ; bm Qf3; pv Qf3 d5 Nxd5 Bxd5 exd5 Rxd5 g4 Qd7 Bg5 Rd6 Rxe5 Bd8 Rxe8+ Qxe8 Bf4 Re6 c4 Ne4 cxb5 axb5 b4 g5 Be3 Ng3+ hxg3 Rxe3 Qf5 Qe6 Qh7+ Kf8 Bxb5;
3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - acd 22;
acs 1434 ; acn 866844561; ce 73 ; bm Nd5; pv Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 b4 Qc8 a4 Bd8 Bg5 Nh7 Bd2 Nf6 h3 Kg8 axb5 axb5 Re2 Qd7 Ra1 Nh5;
Attachment: test.7z - Arena engine analysis from 27 strong chess engines with details (32k)
Parent - - By user923005 (****) [us] Date 2015-09-25 18:50
It is not totally clear that Nd5 is the best move, but clearly it is among the best.  There were several engines that chose it.  There were also some engines that had Nd5 for a while and changed their minds later.
Parent - - By Peter Grayson (****) [gb] Date 2015-10-05 10:02

> It is not totally clear that Nd5 is the best move, but clearly it is among the best.


Hi Dann, I found the same but did you analyse the complete game for mistakes? With clean hash, both Stockfish 031015 and Komodo 9.2 give exactly the same erroneous output in these two positions from the game moves. Other engines I tried quickly change to a winning score for white but it appears as if both Stockfish and Komodo make the mistake of analysing them as draws?

3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - - 3 27


and then a move later ...

3qr3/1b1r1Q2/p2p1bp1/1p2p3/3k4/P3B3/1PP3PP/4R2K b - - 5 28


The complete game with analysis at salient moves below.

Peter

[Event "Wei Yi"]
[Site "?"]
[Date "2015.10.04"]
[Round "?"]
[White "21.Nd5 best?"]
[Black "?"]
[Result "*"]
[ECO "B85"]
[Annotator "Grayson,Peter"]
[PlyCount "71"]

1. e4 c5 2. Nf3 e6 3. Nc3 a6 4. Be2 Nc6 5. d4 cxd4 6. Nxd4 Qc7 7. O-O Nf6 8.
Be3 Be7 9. f4 d6 10. Kh1 O-O 11. Qe1 Nxd4 12. Bxd4 b5 13. Qg3 Bb7 14. a3 Rad8
15. Rae1 Rd7 16. Bd3 Qd8 17. Qh3 g6 18. f5 e5 19. Be3 Re8 20. fxg6 hxg6 21. Nd5
{is this the best?} ({Stockfish 031015 64 POPCNT:} 21. a4 Bc6 22. axb5 axb5 23.
Qf3 Rb7 24. Nd5 Bxd5 25. exd5 Kg7 26. Re2 Rf8 27. Ref2 Nh7 28. Qg4 Bg5 29. Bxg6
Bxe3 30. Bxh7+ Qg5 31. Qxg5+ Bxg5 32. Bd3 b4 33. g3 Ra8 34. b3 Be3 35. Rf5 Re7
36. Be4 Rea7 37. Kg2 Rh8 38. h4 Bd2 39. Bd3 Rh6 40. Kh3 Be3 41. R1f3 Bd2 42. g4
f6 43. Rf1 Ra5 44. Kg3 Be3 {[%eval 91,40]}) ({Komodo 9.2 64-bit:} 21. a4 Bc6
22. axb5 axb5 23. Qf3 d5 24. exd5 Bxd5 25. Nxd5 Rxd5 26. Ra1 Qc8 27. Ra7 Rd7
28. Bxb5 Rxa7 29. Bxa7 Rd8 30. Bb6 Rd6 31. Ba5 Qc5 32. c4 e4 33. Qe2 e3 34. Be1
Re6 35. b4 Qd4 36. c5 Nd5 37. Bc4 Re4 38. Bb3 Kg7 39. Bxd5 Qxd5 40. Bc3+ Kg8
41. Rf3 Qe6 42. Kg1 f5 43. h3 Bf6 44. Bxf6 {[%eval 85,32]}) 21... Nxd5 (21...
Bxd5 {better}) ({Stockfish 031015 64 POPCNT:} 21... Bxd5 22. exd5 Rb7 23. Qf3
Kh8 24. g4 Qc8 25. Bd2 Bd8 26. g5 Nh5 27. a4 Qd7 28. a5 Rc7 29. b4 Kg8 30. Kg1
Nf4 31. Bxf4 exf4 32. Qxf4 Re5 33. h4 Qe7 34. Qf2 Qe8 35. Kg2 Qe7 36. Kg3 Qe8
37. Kh2 Rce7 38. Rxe5 Rxe5 39. Qd4 Re3 40. Kg2 Qe5 41. Qxe5 Rxe5 42. Kf3 f5 43.
gxf6 Bxf6 44. Bxg6 Bxh4 {[%eval 89,43]}) ({Komodo 9.2 64-bit:} 21... Bxd5 22.
exd5 Rb7 23. Bh6 e4 24. Bxe4 Nxe4 25. Rxe4 Bf6 26. Rxe8+ Qxe8 27. c3 Be5 28.
Qf3 a5 29. Qf2 Qc8 30. Bf4 Bxf4 31. Qxf4 Qc4 32. Qxc4 bxc4 33. Rf2 Re7 34. h3
Kg7 35. Rf4 Rc7 36. Kh2 g5 37. Re4 Rc5 38. Kg3 f5 39. Re7+ Kf8 40. Re6 Rxd5 41.
Rg6 Rd3+ 42. Kh2 Kf7 43. Rxg5 Ke6 44. Rg6+ Ke5 45. Rg8 Rd2 46. Rb8 Kf4 47. b4
cxb3 {[%eval 50,36]}) 22. Rxf7 ({Stockfish 031015 64 POPCNT:} 22. Rxf7 Kxf7 23.
Qh7+ Ke6 24. exd5+ Bxd5 25. Bxg6 Bxg2+ 26. Kxg2 d5 27. Qf7+ Kd6 28. Qxe8 Qxe8
29. Bxe8 Rc7 30. c3 Bd8 31. Rg1 Bf6 32. Bg6 Ke6 33. Kf3 Rb7 34. Ke2 a5 35. Rf1
Rg7 36. Bf5+ Kd6 37. Rg1 Rxg1 38. Bxg1 Kc6 39. Bg6 b4 40. cxb4 axb4 41. Be8+
Kd6 42. axb4 e4 43. Bc5+ Ke5 44. b5 d4 45. Bc6 Bg5 46. b6 d3+ 47. Kd1 e3 48. b7
e2+ 49. Ke1 Bh4+ 50. Bf2 Bxf2+ 51. Kxf2 {[%eval 410,40]}) ({Komodo 9.2 64-bit:
} 22. Rxf7 Kxf7 23. Qh7+ Ke6 24. exd5+ Bxd5 25. Bxg6 Bxg2+ 26. Kxg2 d5 27. Qf7+
Kd6 28. Qxe8 a5 29. c3 Bh4 30. Ra1 Qxe8 31. Bxe8 Rg7+ 32. Kh1 b4 33. axb4 axb4
34. Ra6+ Ke7 35. Bg6 bxc3 36. bxc3 d4 37. cxd4 exd4 38. Bxd4 Rg8 39. Kg2 Rc8
40. Kf3 Rc4 41. Be5 Rc1 42. Bf5 Re1 43. Bd4 Kf8 44. Ra7 Rf1+ 45. Kg4 Be7 46. h4
Rd1 47. Be3 Rd6 {[%eval 373,33]}) 22... Kxf7 23. Qh7+ Ke6 24. exd5+ Kxd5 25.
Be4+ Kxe4 26. Qf7 ({Stockfish 031015 64 POPCNT:} 26. c4 Kd3 27. Qxg6+ Be4 28.
Rd1+ Kc2 29. Qxe4+ Kb3 30. Qd3+ Ka2 31. b4 Rf8 32. Rd2+ Ka1 33. Qc3+ Kb1 34.
Qb2# {[%eval 32750,54]}) ({Komodo 9.2 64-bit:} 26. c4 Kd3 27. Qxg6+ Be4 28.
Rd1+ Kc2 29. Qxe4+ Kb3 30. Qd3+ Ka2 31. Qb1+ Kb3 32. Rd3+ Ka4 33. Qd1+ Ka5 34.
b4# {[%eval 32750,24]}) 26... Bf6 27. Bd2+ ({Stockfish 031015 64 POPCNT:} 27.
Qb3 Kf5 28. Rf1+ Kg4 29. Qd3 Rg7 30. Qe2+ Kh4 31. h3 Qd7 32. Kh2 Bxg2 33. Qxg2
Qf5 34. Rxf5 gxf5 35. Qf2+ Kh5 36. Qxf5+ Bg5 37. Bxg5 Rf8 38. Qxf8 Rxg5 39.
Qxd6 Rg6 40. Qxe5+ Rg5 41. Qe8+ Kh6 42. h4 Rg4 43. Qe6+ Rg6 44. Qe5 Kh7 45. h5
Rh6 46. Kh3 Kg8 47. Qg5+ Kh7 48. Qe7+ Kg8 49. Kg4 Rh8 50. Qe8+ Kg7 51. Qg6+ Kf8
52. Qf6+ Ke8 53. Qxh8+ Kd7 54. h6 a5 55. h7 a4 56. Qd4+ Kc6 57. h8=Q Kb7 {
[%eval 5001,48]}) ({Komodo 9.2 64-bit:} 27. Qb3 Kf5 28. Rf1+ Kg4 29. Qd3 Rg7
30. Qe2+ Kh4 31. h3 Qd7 32. Kh2 Bxg2 33. Qxg2 Qf5 34. Rxf5 gxf5 35. Qf2+ Kh5
36. Qxf5+ Bg5 37. Bxg5 Rf8 38. Qxf8 Rxg5 39. Qxd6 a5 40. Qd3 Rg7 41. Qxb5 Re7
42. Qc5 Re8 43. Qc6 Rf8 44. Qe4 Kg5 45. Qxe5+ Rf5 46. h4+ Kg4 47. Qe4+ Rf4 48.
Qg2+ Kf5 49. Qd5+ Kg4 50. Qg5+ Kf3 51. h5 Rf8 52. h6 a4 53. h7 Ra8 54. Qg2+ Ke3
{[%eval 25000,45]}) 27... Kd4 ({Stockfish 031015 64 POPCNT:} 27... Kd4 28. Be3+
Ke4 {[%eval 0,51] What's going on here?}) ({Komodo 9.2 64-bit:} 27... Kd4 28.
Be3+ Ke4 {[%eval 0,45] Making same erroneous score as Stockfish?}) ({Houdini 4
Pro x64 GTB:} 27... Kd4 28. Be3+ Ke4 29. Qb3 Kf5 30. Rf1+ Kg4 31. Qd3 Rg7 32.
Bd2 Kh5 33. Qe2+ Kh4 34. Qe1+ Kh5 35. Qd1+ Kh4 36. h3 Qd7 37. Kh2 Bxg2 38. Qe1+
Kh5 39. Qe2+ Kh4 40. Qxg2 Qf5 41. Rxf5 gxf5 42. Qf2+ Kh5 43. Qxf5+ Bg5 44. Bxg5
Rf8 45. Qxf8 Rxg5 46. Qxd6 e4 47. Qxa6 Rf5 48. Qe6 Rf2+ 49. Kg3 Rf3+ 50. Kg2
Kg5 51. Qxe4 Rf5 52. Kg3 Rf1 53. h4+ Kh6 54. Qe3+ Kg7 55. Qd4+ Kh6 56. Qd2+ Kg7
57. Qd7+ Kh8 58. Qd8+ Kg7 59. Qd4+ Kh6 {[%eval 1401,28]}) 28. Be3+ Ke4 ({
Komodo 9.2 64-bit:} 28... Ke4 {[%eval 0,99]}) ({Stockfish 031015 64 POPCNT:}
28... Ke4 {[%eval 0,127]}) 29. Qb3 Kf5 ({Stockfish 031015 64 POPCNT:} 29... Kf5
30. Rf1+ Kg4 31. Qd3 Rg7 32. Qe2+ Kh4 33. h3 Qd7 34. Kh2 Bxg2 35. Qxg2 Qf5 36.
Rxf5 gxf5 37. Qf2+ Kh5 38. Qxf5+ Bg5 39. Bxg5 Rf8 40. Qxf8 Rxg5 41. Qxd6 Rf5
42. Qe6 Rf2+ 43. Kg3 Rf1 44. Qxa6 Rb1 45. Qxb5 Re1 46. Kf2 Rb1 47. Qxe5+ Kg6
48. Kg3 Kh7 49. h4 Kg6 50. Qe6+ Kg7 51. h5 Ra1 52. Qe7+ Kh6 53. Qf7 Rg1+ 54.
Kf2 Rg7 55. Qxg7+ Kxg7 56. h6+ Kf6 57. Kg3 Ke5 58. h7 Kd6 {[%eval 5252,50]})
30. Rf1+ Kg4 31. Qd3 Bxg2+ 32. Kxg2 Qa8+ 33. Kg1 Bg5 34. Qe2+ Kh4 35. Bf2+ Kh3
36. Be1
Parent - By user923005 (****) [us] Date 2015-10-05 18:33
I will take a look.
I did notice that those engines that chose Nd5 did not expect the blunder follow-on move.
It seems to me that the best move is not cast in stone yet.
I will take a close look at your two intermediate positions.
It may be that both K and SF are right that they are draw positions, or it could easily be that aggressive pruning removes an important tactic.
Parent - - By Lazy Frank (****) [lv] Date 2015-10-05 20:33
Peter! After a4 Bc6 (!?) axb5 axb5 Ra1(!)

3qr1k1/3rbp2/2bp1np1/1p2p3/4P3/2NBB2Q/1PP3PP/R4R1K b - - 1 23
Parent - - By Peter Grayson (****) [gb] Date 2015-10-05 22:55

> After a4 Bc6 (!?) axb5 axb5 Ra1(!)


Thanks Raivis. I wonder how much influence the amount of hash given to the engine has on the moves further down the ply chain? It certainly affected Houdini's output in some positions but I have not tested much with Stockfish. In Rybka and Houdini, some hash sizes seemed to give consistently better analysis than other sizes.

I'm just running the Stockfish 051015 64 POPCNT engine with this position and it prefers a different line to the 031015 version but still does not consider 21.Nd5

21.a4 bxa4 22.Bc4 a3 23.b3 Rc7 24.Bb6 Kg7 25.Nd5 Bxd5 26.Bxd5 Qc8 27.Bxc7 Qxc7 28.Qf3 Rf8 29.Qd3 Qc5 30.Qxa6 Nh5 31.Rf3 Qxc2 32.Ref1 Nf4 33.R3f2 Qc7 34.Qxa3 Nxd5 35.exd5 f5 36.b4 Qc4 37.Rd1 Rc8 38.Qa4 Qc7 39.Rf3 e4 40.Rh3 Bf6 41.Rf1 Kg8 42.Rg3 Qh7 43.Rh3
  +/-  (0.75)   Depth: 40/68   00:22:07  25899MN

After seeing what is still happening with 051015's scoring as Black for the game moves 27..Kd4 and 28..Ke4 I'm uncertain on the integrity of the analysis being produced on the machine.

Peter
Parent - - By user923005 (****) [us] Date 2015-10-06 02:11
You are using essentially the same version as I am (code pulled from the repository today).
I make some customizations, but they should have zero effect on play.

I generally set up an analysis session with the following:
setoption name SyzygyPath value C:\chess\syzygy
setoption name MultiPV value 1 
setoption name Hash value 4096
setoption name Threads value 11


Folder C:\chess\syzygy is an SSD.
To run this particular pass, I used the bench command (my modifications write the output to disk) like this:
bench 2048 10 1800000 q:\pgrayson.epd time

Very strange that your binary behaves so differently.
Parent - - By Peter Grayson (****) [gb] Date 2015-10-06 06:20
I'm using 5 man syzygy but the output is the same whether or not TB's are used. The engine in XP home 32 bit, XP Pro 64 bit (2 quad machines dual boot option for each XP O/S) and Windows 7 Pro on the dual Xeon all give that rapidly progressing output as though it were a draw. Strange that the few moves that it gives still take it down the right route. As White it has no problem seeing the win but only those two erroneous scores for moves 27 and 28 as Black.

No difference in multipv mode with only two possible moves after 27.Bd2 ..

1: 21.Nd5 best?, Wei Yi

Analysis by Stockfish 051015:
at 47 ply depth:

1. =  (0.00): 27...Kd4 28.Be3+ Ke4
2. +-  (#5): 27...Kf5 28.Rf1+ Bf3 29.Rxf3+ Ke4 30.Qb3 Kd4 31.Be3+ Ke4 32.Qd3#

Very strange indeed that the behaviour should be different but I wondered if it was the case that with the alternative move leading to mate then the only other move is selected without doing much real analysis that explains how quickly it ramps through the ply. In that case perhaps it is not too much of a concern although I had expected the output to be more precise in analysis mode.

I tried the much earlier Stockfish 1.8 JA engine and it does the same but slower.

1: 21.Nd5 best?, Wei Yi

Analysis by Stockfish 1.8 JA:

27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 29   00:00:13  56075kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 30   00:00:17  76231kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 31   00:00:23  103mN

>bench 2048 10 1800000 q:\pgrayson.epd time


When run directly in the binary, the output is different compared to running in a GUI ... the 32 bit output attached
Parent - - By user923005 (****) [us] Date 2015-10-06 09:02
Sounds like analyze is broken
Parent - By Peter Grayson (****) [gb] Date 2015-10-06 10:30
Must be something different the GUI's are sending the engine. Getting the same as you from the binary also on the dual Xeon machine ...

bench 4096 16 16800 c:\Position\Stockfish.epd time

Position: 1/1
info depth 1 seldepth 1 multipv 1 score cp 381 nodes 49 nps 24500 tbhits 0 time
2 pv e4d4 f7g6
info depth 2 seldepth 3 multipv 1 score cp 64 nodes 184 nps 46000 tbhits 0 time
4 pv e4f5 e1f1 f5g4 f7g6 f6g5 d2g5 d8g5 g6e8
info depth 3 seldepth 5 multipv 1 score cp 64 nodes 262 nps 32750 tbhits 0 time
8 pv e4f5 e1f1 f5g4 f7g6 f6g5
info depth 4 seldepth 7 multipv 1 score cp 0 nodes 453 nps 34846 tbhits 0 time 1
3 pv e4f5 e1f1 f5e4 f1e1
info depth 5 seldepth 7 multipv 1 score cp 0 nodes 524 nps 29111 tbhits 0 time 1
8 pv e4f5 e1f1 f5e4 f1e1
info depth 6 seldepth 7 multipv 1 score cp 0 nodes 588 nps 26727 tbhits 0 time 2
2 pv e4f5 e1f1 f5e4 f1e1
info depth 7 seldepth 7 multipv 1 score cp 0 nodes 731 nps 27074 tbhits 0 time 2
7 pv e4f5 e1f1 f5e4 f1e1
info depth 8 seldepth 7 multipv 1 score cp 0 nodes 827 nps 26677 tbhits 0 time 3
1 pv e4f5 e1f1 f5e4 f1e1
info depth 9 seldepth 9 multipv 1 score cp 0 nodes 3838 nps 103729 tbhits 0 time
37 pv e4d4 d2e3 d4e4 e3d2
info depth 10 seldepth 9 multipv 1 score cp 0 nodes 6107 nps 148951 tbhits 0 tim
e 41 pv e4d4 d2e3 d4e4 e3d2
info depth 11 seldepth 9 multipv 1 score cp 0 nodes 10000 nps 217391 tbhits 0 ti
me 46 pv e4d4 d2e3 d4e4 e3d2
info depth 12 seldepth 9 multipv 1 score cp 0 nodes 15191 nps 297862 tbhits 0 ti
me 51 pv e4d4 d2e3 d4e4 e3d2
info depth 13 seldepth 9 multipv 1 score cp 0 nodes 26605 nps 475089 tbhits 0 ti
me 56 pv e4d4 d2e3 d4e4 e3d2
info depth 14 seldepth 9 multipv 1 score cp 0 nodes 35851 nps 587721 tbhits 0 ti
me 61 pv e4d4 d2e3 d4e4 e3d2
info depth 15 seldepth 9 multipv 1 score cp 0 nodes 46919 nps 721830 tbhits 0 ti
me 65 pv e4d4 d2e3 d4e4 e3d2
info depth 16 seldepth 9 multipv 1 score cp 0 nodes 78207 nps 1101507 tbhits 0 t
ime 71 pv e4d4 d2e3 d4e4 e3d2
info depth 17 seldepth 9 multipv 1 score cp 0 nodes 98744 nps 1316586 tbhits 0 t
ime 75 pv e4d4 d2e3 d4e4 e3d2
info depth 18 seldepth 9 multipv 1 score cp 0 nodes 131054 nps 1617950 tbhits 0
time 81 pv e4d4 d2e3 d4e4 e3d2
info depth 19 seldepth 9 multipv 1 score cp 0 nodes 175577 nps 2018126 tbhits 0
time 87 pv e4d4 d2e3 d4e4 e3d2
info depth 20 seldepth 9 multipv 1 score cp 0 nodes 231019 nps 2511076 tbhits 0
time 92 pv e4d4 d2e3 d4e4 e3d2
info depth 21 seldepth 9 multipv 1 score cp 0 nodes 314914 nps 3180949 tbhits 0
time 99 pv e4d4 d2e3 d4e4 e3d2
info depth 22 seldepth 9 multipv 1 score cp 0 nodes 466451 nps 1014023 tbhits 0
time 460 pv e4d4 d2e3 d4e4 e3d2
info depth 23 seldepth 9 multipv 1 score cp 0 nodes 589531 nps 1251658 tbhits 0
time 471 pv e4d4 d2e3 d4e4 e3d2
info depth 24 seldepth 9 multipv 1 score cp 0 nodes 739041 nps 1523795 tbhits 0
time 485 pv e4d4 d2e3 d4e4 e3d2
info depth 25 seldepth 47 multipv 1 score cp -680 nodes 6805869 nps 6966089 tbhi
ts 0 time 977 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h3 g4h4 d3e2 d8c
8 h1h2 b7g2 e2g2 c8f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f8 g7g5 f8d6 g5g
6 d6e5 h5h6 b2b3 g6g5 e5f6 g5g6 f6f5
info depth 26 seldepth 48 multipv 1 score cp -729 nodes 8761576 nps 7645354 hash
full 13 tbhits 0 time 1146 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h3
g4h4 d3e2 d8c8 h1h2 b7g2 e2g2 c8f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f8
g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 g6f6 h2g3 f6g6 g3f4 g6f6 f4e5 f6g6 e4d3 h5h6 d3f5
info depth 27 seldepth 48 multipv 1 score cp -737 nodes 10808130 nps 8288443 has
hfull 20 tbhits 0 time 1304 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h3
g4h4 d3e2 d8c8 h1h2 b7g2 e2g2 c8f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f8
g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 h5h6 e4e5 g6g5 e5h8 h6g6 h8c8 g6h5 c8a6 g5c5 a6e6
c5c2 h2g3
info depth 28 seldepth 48 multipv 1 score cp -751 nodes 13473186 nps 8994116 has
hfull 22 tbhits 0 time 1498 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h3
g4h4 d3e2 d8c8 h1h2 b7g2 e2g2 c8f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f8
g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 g6f6 h2g3 h5h6 g3g4 h6g7 e4e7 f6f7 e7g5 g7h7 g5h5
h7g7 h5e5 g7h7 e5d6
info depth 29 seldepth 52 multipv 1 score cp -789 nodes 17882113 nps 9890549 has
hfull 33 tbhits 0 time 1808 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h3
g4h4 d3e2 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f8
g7g5 f8d6 a6a5 d6d3 h5h6 d3b5 g5h5 b5a5 h6g6 a5c3 g6f6 c3c6 f6f5 c6f3 f5g6 f3g4
h5g5 g4e6 g6h5 e6e8 h5h6 e8e7
info depth 30 seldepth 54 multipv 1 score cp -818 nodes 24936398 nps 11102581 ha
shfull 41 tbhits 0 time 2246 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h
3 g4h4 d3e2 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f
8 g7g5 f8d6 a6a5 d6d3 g5g7 d3b5 g7e7 b5a5 h5g6 a5d8 g6f6 h3h4 e5e4 h2g2 f6e6 g2f
2 e7g7 d8c8 e6f6 c8c3 f6g6
info depth 31 seldepth 61 multipv 1 score cp -837 lowerbound nodes 39006297 nps
12793144 hashfull 58 tbhits 0 time 3049 pv e4d4
info depth 31 currmove e4d4 currmovenumber 1
info depth 31 seldepth 61 multipv 1 score cp -860 upperbound nodes 42909798 nps
13166553 hashfull 62 tbhits 0 time 3259 pv e4d4 d2e3
info depth 31 currmove e4d4 currmovenumber 1
info depth 31 seldepth 67 multipv 1 score cp -878 nodes 47861504 nps 13663004 ha
shfull 63 tbhits 0 time 3503 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 h2h
3 g4h4 d3e2 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f
8 g7g5 f8d6 a6a5 d6d3 g5g7 d3b5 g7e7 b5a5 h5g6 a5d8 e7f7 h3h4 g6f5 d8g5 f5e6 h2g
3 f7f5 g5g6 f5f6 g6g8 e6d6 c2c4 d6e7 g8d5 f6g6 g3f3 e7f6 d5d6 f6f5 d6d7 f5f6
info depth 32 currmove e4d4 currmovenumber 1
info depth 32 seldepth 67 multipv 1 score cp -884 upperbound nodes 53546190 nps
14079986 hashfull 73 tbhits 0 time 3803 pv e4d4 d2e3
info depth 32 currmove e4d4 currmovenumber 1
info depth 32 currmove e4f5 currmovenumber 2
info depth 32 seldepth 67 multipv 1 score cp -888 nodes 60139830 nps 14491525 ha
shfull 85 tbhits 0 time 4150 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 d3e
2 g4h4 h2h3 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5f
8 g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 h5h6 e4h4 h6g7 h4e7 g7h6 h3h4 g6c6 e7f8 h6h7 f8f
5 h7h6 h2h3 c6g6 f5e5 h6h7 h4h5 g6g7 e5f5 h7g8 f5e6 g8h7 e6a6 g7g5 h3h4
info depth 33 currmove e4d4 currmovenumber 1
info depth 33 seldepth 67 multipv 1 score cp -894 upperbound nodes 68998062 nps
15068369 hashfull 99 tbhits 0 time 4579 pv e4d4 d2e3
info depth 33 currmove e4d4 currmovenumber 1
info depth 33 seldepth 67 multipv 1 score cp -901 upperbound nodes 73029773 nps
15239935 hashfull 100 tbhits 0 time 4792 pv e4d4 d2e3
info depth 33 currmove e4d4 currmovenumber 1
info depth 33 seldepth 67 multipv 1 score cp -894 lowerbound nodes 75686460 nps
15336668 hashfull 105 tbhits 0 time 4935 pv e4d4
info depth 33 currmove e4d4 currmovenumber 1
info depth 33 seldepth 67 multipv 1 score cp -902 upperbound nodes 79012969 nps
15426194 hashfull 109 tbhits 0 time 5122 pv e4d4 d2e3
info depth 33 currmove e4d4 currmovenumber 1
info depth 33 seldepth 67 multipv 1 score cp -896 nodes 87139935 nps 15832110 ha
shfull 111 tbhits 0 time 5504 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 d3
e2 g4h4 h2h3 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f5
f8 g7g5 f8d6 a6a5 d6d3 g5g7 d3b5 g7e7 b5a5 h5g6 a5d8 g6f6 d8d6 f6f7 h2g3 e7e6 d6
d7 e6e7 d7f5 f7g7 f5g5 g7f7 g3f3 f7e6 f3e4 e7c7 g5e5 e6d7 e5d5 d7c8 e4f3
info depth 34 currmove e4d4 currmovenumber 1
info depth 34 seldepth 67 multipv 1 score cp -903 upperbound nodes 95063512 nps
16068883 hashfull 128 tbhits 0 time 5916 pv e4d4 d2e3
info depth 34 currmove e4d4 currmovenumber 1
info depth 34 seldepth 67 multipv 1 score cp -909 upperbound nodes 98127767 nps
16052309 hashfull 133 tbhits 0 time 6113 pv e4d4 d2e3
info depth 34 currmove e4d4 currmovenumber 1
info depth 34 seldepth 67 multipv 1 score cp -903 lowerbound nodes 107948622 nps
16448060 hashfull 147 tbhits 0 time 6563 pv e4d4
info depth 34 currmove e4d4 currmovenumber 1
info depth 34 seldepth 67 multipv 1 score cp -910 upperbound nodes 112340854 nps
16489190 hashfull 151 tbhits 0 time 6813 pv e4d4 d2e3
info depth 34 currmove e4d4 currmovenumber 1
info depth 34 seldepth 67 multipv 1 score cp -910 nodes 115835682 nps 16583490 h
ashfull 154 tbhits 0 time 6985 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 d
3e2 g4h4 h2h3 d8c8 h1h2 b7g2 e2g2 c8f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f
5f8 g7g5 f8d6 a6a5 d6d3 g5g7 d3b5 g7e7 b5a5 h5g6 a5d8 g6f6 d8d6 f6f7 h2g3 e7e6 d
6d7 e6e7 d7f5 f7g8 f5c8 g8g7 g3f3 e5e4 f3e3 e7f7 c8g4 g7f8 h3h4 f7f1 e3e4 f1e1 e
4d5
info depth 35 currmove e4d4 currmovenumber 1
info depth 35 seldepth 67 multipv 1 score cp -917 upperbound nodes 125035898 nps
16778837 hashfull 175 tbhits 0 time 7452 pv e4d4 d2e3
info depth 35 currmove e4d4 currmovenumber 1
info depth 35 seldepth 67 multipv 1 score cp -918 nodes 136582266 nps 16962526 h
ashfull 193 tbhits 0 time 8052 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7 d
3e2 g4h4 h2h3 d8c8 h1h2 b7g2 e2g2 c8f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8 f
5f8 g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 h5h6 e4e5 g6g5 e5e3 h6h5 e3e8 h5h6 h3h4 g5g4 h
2h3 g4g7 e8e5 h6h7 e5f5 h7g8 f5c8 g8h7 c8a6 g7e7 a6b5
info depth 36 currmove e4d4 currmovenumber 1
info depth 36 seldepth 71 multipv 1 score cp -924 upperbound nodes 189813969 nps
18603740 hashfull 237 tbhits 0 time 10203 pv e4d4 d2e3
info depth 36 currmove e4d4 currmovenumber 1
info depth 36 seldepth 71 multipv 1 score cp -924 nodes 201390962 nps 18786470 h
ashfull 254 tbhits 0 time 10720 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7
d3e2 g4h4 h2h3 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8
f5f8 g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 h5h6 e4e5 g6g5 e5e3 h6h5 e3e8 h5h6 h3h4 g5g4
h2h3 g4g7 e8e5 h6h7 e5f5 h7g8 f5e6 g8f8 e6a6 f8f7 a6b5 f7e6 b5c6 e6f5 c6c5 f5e6
c5h5 e6f6 h5f3 f6e6 f3e4 e6f6
info depth 37 currmove e4d4 currmovenumber 1
info depth 37 seldepth 71 multipv 1 score cp -930 upperbound nodes 232113006 nps
19379895 hashfull 286 tbhits 0 time 11977 pv e4d4 d2e3
info depth 37 currmove e4d4 currmovenumber 1
info depth 37 seldepth 71 multipv 1 score cp -930 nodes 248278274 nps 19551009 h
ashfull 315 tbhits 0 time 12699 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7
d3e2 g4h4 h2h3 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8
f5f8 g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 h5h6 e4e5 g6g5 e5e3 h6h5 e3e8 h5h6 h3h4 g5g4
h2h3 g4g7 e8e5 h6h7 e5f5 h7g8 f5e6 g8f8 e6a6 f8f7 a6b5 f7e6 b5b6 e6d5 b6b3 d5d6
b3d3 d6e6 d3e4 e6f6
info depth 38 currmove e4d4 currmovenumber 1
info depth 38 seldepth 71 multipv 1 score cp -936 upperbound nodes 275533842 nps
19948873 hashfull 342 tbhits 0 time 13812 pv e4d4 d2e3
info depth 38 currmove e4d4 currmovenumber 1
info depth 38 seldepth 71 multipv 1 score cp -936 nodes 301336262 nps 20249732 h
ashfull 372 tbhits 0 time 14881 pv e4d4 d2e3 d4e4 f7b3 e4f5 e1f1 f5g4 b3d3 d7g7
d3e2 g4h4 h2h3 d8d7 h1h2 b7g2 e2g2 d7f5 f1f5 g6f5 g2f2 h4h5 f2f5 f6g5 e3g5 e8f8
f5f8 g7g5 f8d6 e5e4 d6e7 g5g6 e7e4 h5h6 e4e5 g6g5 e5e3 h6h5 e3e8 h5h6 e8c8 h6h5
c8a6 g5c5 a6e6 c5g5 e6e8 h5h6 h3h4 g5g4 h2h3 g4g7 e8b5 g7g6 b5e5 g6a6 e5g5 h6h7
info depth 39 currmove e4d4 currmovenumber 1
info depth 39 seldepth 71 multipv 1 score cp -943 upperbound nodes 346112860 nps
20748927 hashfull 416 tbhits 0 time 16681 pv e4d4 d2e3
info depth 39 currmove e4d4 currmovenumber 1
info nodes 350657251 time 16808
bestmove e4d4 ponder d2e3

===========================
Total time (ms) : 16812
Nodes searched  : 350657251
Nodes/second    : 20857557
Parent - By Peter Grayson (****) [gb] Date 2015-10-06 10:42 Edited 2015-10-06 10:44
Thought I'd check exactly what the GUI - Engine communication is. Interesting that only Arena and HIARCS GUIs send the correct full position detail. Neither Fritz nor Shredder send the 50 move or game move counters. Nonetheless, none of them showed a different output from the engine! The uci logging engine here was Houdini not Stockfish.

Deep Fritz 13 GUI

[2015/10/06 11:13:20] uci
[2015/10/06 11:13:20] setoption name Hash value 16384
[2015/10/06 11:13:30] setoption name GaviotaTbCache value 64
[2015/10/06 11:13:30] setoption name GaviotaTbPath value C:\Gaviota EGTB
[2015/10/06 11:13:32] isready
[2015/10/06 11:13:54] setoption name Clear Hash
[2015/10/06 11:14:00] position fen
3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - - 0 0

[2015/10/06 11:14:00] go infinite
[2015/10/06 11:14:13] stop
[2015/10/06 11:14:13] > bestmove e4d4 ponder d2e3
[2015/10/06 11:14:15] setoption name Clear Hash
[2015/10/06 11:14:18] quit

Deep Shredder 10 GUI

[2015/10/06 11:19:08] uci
[2015/10/06 11:19:23] setoption name Hash value 4096
[2015/10/06 11:19:32] isready
[2015/10/06 11:19:32] setoption name Ponder value true
[2015/10/06 11:19:32] isready
[2015/10/06 11:19:50] ucinewgame
[2015/10/06 11:19:50] isready
[2015/10/06 11:19:50] position fen
3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - -
moves
[2015/10/06 11:19:51] go infinite
[2015/10/06 11:20:11] stop
[2015/10/06 11:20:11] > bestmove e4d4 ponder d2e3
[2015/10/06 11:20:18] quit

Arena 3.5 GUI

[2015/10/06 11:23:05] xboard
[2015/10/06 11:23:05] uci
[2015/10/06 11:23:05] setoption name Hash value 4096
[2015/10/06 11:23:05] setoption name Threads value 16
[2015/10/06 11:23:05] setoption name Split_Depth value 10
[2015/10/06 11:23:05] setoption name Ponder value false
[2015/10/06 11:23:05] setoption name Contempt value 1
[2015/10/06 11:23:05] setoption name Analysis_Contempt value false
[2015/10/06 11:23:05] setoption name MultiPV value 1
[2015/10/06 11:23:05] setoption name GaviotaTbPath value <empty>
[2015/10/06 11:23:05] setoption name GaviotaTbCache value 64
[2015/10/06 11:23:05] setoption name Hard_Probe_Depth value 24
[2015/10/06 11:23:05] setoption name Soft_Probe_Depth value 16
[2015/10/06 11:23:05] isready
[2015/10/06 11:23:39] ucinewgame
[2015/10/06 11:23:39] isready
[2015/10/06 11:23:39] position fen
3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - - 3 27

[2015/10/06 11:23:39] go movetime 240000
[2015/10/06 11:23:57] stop
[2015/10/06 11:23:57] > bestmove e4d4 ponder d2e3
[2015/10/06 11:24:08] quit

HIARCS HCE 1.8

[2015/10/06 11:27:21] uci
[2015/10/06 11:27:21] quit

[2015/10/06 11:27:41] uci
[2015/10/06 11:27:41] setoption name Hash value 16384
[2015/10/06 11:27:51] isready
[2015/10/06 11:27:51] ucinewgame
[2015/10/06 11:27:51] isready
[2015/10/06 11:27:51] position fen
3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - - 3 27

[2015/10/06 11:27:54] go infinite
[2015/10/06 11:28:22] stop
[2015/10/06 11:28:22] > bestmove e4d4 ponder d2e3
[2015/10/06 11:28:29] quit
Parent - - By user923005 (****) [us] Date 2015-10-05 20:42
Latest bleeding edge stockfish sees immediately (less than one second) that this position is lost for black:

Searching:
3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - - 0 1

infinite: 0 ponder: 0 time: 0 increment: 0 moves to go: 0

1   +3.81   00:00      49  Kd4 Qxg6
2   +0.64   00:00     186  Kf5 Rf1+ Kg4 Qxg6+ Bg5 Bxg5 Qxg5 Qxe8
3   +0.64   00:00     272  Kf5 Rf1+ Kg4 Qxg6+ Bg5
4   +0.00   00:00     468  Kf5 Rf1+ Ke4 Re1+
5   +0.00   00:00     543  Kf5 Rf1+ Ke4 Re1+
6   +0.00   00:00     611  Kf5 Rf1+ Ke4 Re1+
7   +0.00   00:00     758  Kf5 Rf1+ Ke4 Re1+
8   +0.00   00:00     858  Kf5 Rf1+ Ke4 Re1+
9   +0.00   00:00    3876  Kd4 Be3+ Ke4 Bd2+
10   +0.00   00:00    6136  Kd4 Be3+ Ke4 Bd2+
11   +0.00   00:00   10072  Kd4 Be3+ Ke4 Bd2+
12   +0.00   00:00   15465  Kd4 Be3+ Ke4 Bd2+
13   +0.00   00:00   23762  Kd4 Be3+ Ke4 Bd2+
14   +0.00   00:00   38435  Kd4 Be3+ Ke4 Bd2+
15   +0.00   00:00   50862  Kd4 Be3+ Ke4 Bd2+
16   +0.00   00:00   64225  Kd4 Be3+ Ke4 Bd2+
17   +0.00   00:00   96853  Kd4 Be3+ Ke4 Bd2+
18   -5.56   00:00   1160K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Bf6+ Kh6 Bxg7+ Kxg7 Qd7+ Rf7 Qxd6
19   -5.68   00:00   1267K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Bf6+ Kh6 Bxg7+ Kxg7 Qd7+ Rf7 Qxd6 Rf2+ Kg3 Rxc2
20   -6.59   00:00   1569K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Rf2+ Kg3 Rxc2 Qxb5
21   -6.75   00:00   1839K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qe5+ Kh6 Qxe4 Rf6
22   -6.89   00:00   2160K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qe5+ Kh6 c3 Rg7
23   -6.93   00:00   2855K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qxe4 Kh6 Qe5 Rg7 Qe3+ Kh5 Qf3+ Kg5 Qd5+ Kh6 Qd6+ Rg6
24   -7.22   00:00   3616K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qxe4 Kh6 Qe5 Rg5 Qf4 Kg6 Qd6+ Kf7 Qxa6 Re5
25   -7.28   00:00   4261K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Kh6 Qxe4 Rg8 Qe3+ Kh5 Qe5+ Rg5 Qe2+ Kh6 h4 Rg6 Qe5
26   -7.31   00:01   6261K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qxe4 Kg5 Kg3 Kf6+ Kf4 Kf7 h4 Rf6+ Kg5 Re6 Qf3+ Ke7 Qb7+ Ke8 Qa8+ Kf7
27   -7.50   00:01   8096K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Kh6 Qxe4 Rg8 Qe3+ Kh5 Qe5+ Kh6 h4 Rg4 Kh3 Rc4 Qf6+ Kh7
28   -7.57   00:01   9687K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Kh6 Qxe4 Rg8 Qe3+ Kh5 Qe5+ Rg5 Qe2+ Kh6 h4 Rg6 Qe5 Kh7 Qe7+ Rg7 Qe4+ Kh6 Qe5 Rf7
29   -8.24   00:02  16270K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qxe4 Kg5 Qe5+ Kh6 h4 Kh7 h5 Rg8 Qf5+ Kh6 Qe6+ Kh7 Qf7+ Kh8 Kh3 a5 Qf5 Kg7 Qxb5
30   -8.46   00:03  24031K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Rg6 Qxe4 Rf6 Kg3 Kh6 h4 Rg6+ Kf4 Rf6+ Ke5 Rf8 Qe3+ Kg6 Qg5+ Kh7 Qe7+ Kg8 Qb7 Rf2 Qa8+ Kg7 Qa7+ Rf7 Qxa6 Re7+ Kf4
31   -8.61   00:05  33800K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Kh6 Qxe4 Kg7 h4 Rg6 Qe7+ Kg8 h5 Rh6 Qg5+ Kh7 Qe5 Kg8 Kg3 Kf7 Qd5+ Kf8 Kf4 Kg7 Kg5 Rf6 Qb7+ Rf7
32   -8.80   00:06  45682K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Kh6 Qxe4 Kg7 h4 Rg6 Qe7+ Kg8 h5 Rh6 Qg5+ Kh7 Qe5 Kg8 Kg3 Kf7 Qd5+ Kf8 Kf4 Rh7 Qd8+ Kf7 Qd7+ Kg8 Qe8+ Kg7 Qe7+ Kg8
33   -8.93   00:09  66016K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Rg7 Qxb5 Re7 Qc5 Re8 Qc6 Rf8 Qe6 Rf2+ Kg3 Rf1 Qxe5+ Kg6 Qxa5 Rg1+ Kf2 Rg5 Qa6+ Kf7 Qc4+ Kf6 Qc6+ Ke5 Qe8+ Kf6
34   -9.78   00:15 121112K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 e4 Qe7 Kh6 Qxe4 Rg6 Qe5 Kh7 h4 Kg8 h5 Rg7 Kh3 Kh7 Qf5+ Kh8 Qc8+ Kh7 Qxa6 Rg8 Qxb5 Kh6 Qc6+ Kh7 Qf3 Rg7 Qe4+ Kh6 Kh4 Rg8 Qe6+ Kh7 Qd7+ Kh6
35   -9.84   00:18 147132K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qc8 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Rg7 Qxb5 Re7 Qc5 Re6 Qd5 Re7 Qd6 Rh7 Qxe5+ Kg6 Qxa5 Rh5 Qb6+ Kf7 Qa7+ Kf6 Qd4+ Ke6 Qg4+ Rf5 h4 Ke5 h5 Rf4 Qg7+ Ke6
36  -10.51   00:31 253000K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rg6 Qxe5+ Kh6 h4 Kh7 Qe4 Kg7 Qe7+ Kh6 Qe3+ Kh7 Qe5 Kg8 h5 Rg7 Kh3 b4 axb4 Kh7 Qf5+ Kh8 Qf6 Kh7 Qxa6 Rg5 Qe6 Rg7 b5
37  -10.68   00:35 287506K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Rg7 Qxb5 Re7 Qc5 Re6 Qd5 Ra6 Qxe5+ Kg6 Qe4+ Kh6 h4 a4 Kh3 Rf6 Qxa4 Rf3+ Kg2 Rf6 Qb5 Kg7 Kh2 Rf2+ Kg3 Rf8 h5 Rg8 Kh3
38  -10.72   00:43 348786K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Rg7 Qxb5 Re7 Qc5 Re6 Qd5 Ra6 Qxe5+ Kg6 Qe4+ Kh6 h4 a4 Kh3 Rf6 Qxa4 Rf3+ Kg2 Rf6 Qb5 Kg7 Kh2 Rf2+ Kg3 Rf8 h5 Rg8 Kh3 Kf6 Qc6+ Kf7 Qc4+ Kf8 Qf4+ Ke7
39  -13.66   01:05 542038K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Rg7 Qxb5 Re7 Qc5 Re6 Qd5 Ra6 Qxe5+ Kg6 Qe4+ Kh6 h4 a4 Kh3 Rf6 Qxa4 Rf3+ Kg2 Rf7 Qb5 Kg7 Kg3 Kh7 h5 Rg7+ Kh3 Rg8 Qf5+ Kh8 Kh2 Rg7 h6 Ra7 Qe5+ Kh7
40  -20.75   01:42 862975K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 a4 Qxe5 Rf1 Qh8+ Kg6 Qe8+ Kg7 Qxa4 Rb1 Qf4 Re1 Qg4+ Kf7 Qf5+ Ke8 h5 Rg1+ Kf2 Rd1 h6 Rd2+ Kg3
41  -46.16   01:56 979596K  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 a4 Qxe5 Rf1 Qe3+ Kg7 Qd4+ Kf8 Qxa4 Rd1 Qe4 Ra1 Qe5 Rb1 Kh2 Kf7 Qc5 Ke8 Qg1 Rxg1 Kxg1 Kd8 h5 Kc8
42  -43.09   02:08   1075M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Kg6 Qf6+ Kh7 Qh6+ Kg8 Bf6 Rd7 Qh8+ Kf7 Qg7+ Ke6 Qg4+ Kd5 Qxd7 e4 Qb7+ Ke6 Qxa6 Kd7 Qxb5+ Ke6 Qe8+ Kxf6 Qxe4 Kf7 Qd5+ Ke7 Qxd6+ Kxd6 h4 Kd5
43  -43.09   02:11   1093M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Kg6 Qf6+ Kh7 Qh6+ Kg8 Bf6 Rd7 Qh8+ Kf7 Qg7+ Ke6 Qg4+ Kd5 Qxd7 e4 Qb7+ Ke6 Qxa6 Kd7 Qxb5+ Ke6 Qe8+ Kxf6 Qxe4 Kf7 Qd5+ Ke7 Qxd6+ Kxd6 h4 Kd5
44  -41.62   02:36   1283M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 Rf5 Qa6+ Kg7 Qe6 Rf1 Qxe5+ Kg6 h5+ Kf7 Qxa5 Ra1 Qf5+ Ke7 Qe5+ Kd8 h6 Rf1 Qd5+ Ke7
45  -37.50   03:26   1693M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 Rf5 Qd3 e4 Qe3+ Kg7 Qxe4 Kf6 Qxf5+ Kxf5 b4 a4 Kh2 Ke4 h5
46  -42.20   03:43   1829M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 Rf5 Qa6+ Kg7 Qe6 Rf1 Qxe5+ Kf7 Qd5+ Kg7 Qxa5 Rg1+ Kh2 Rb1 Qa4 Kh6 Qg4 Rf1 Qe6+ Kg7
47  -42.20   04:07   2011M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 Rf5 Qd3 e4 Qe3+ Kg7 Qxe4 Rf1 Qe5+ Kf7 Qd5+ Kg7 Qxa5 Rg1+ Kh2 Rb1 Qa4 Kf6 Qf4+ Ke7 Qe3+ Kd8 Qg5+ Kc7
48  -42.20   04:11   2041M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 Rf5 Qd3 e4 Qe3+ Kg7 Qxe4 Rf1 Qe5+ Kf7 Qd5+ Kg7 Qxa5 Rg1+ Kh2 Rb1 Qa4 Kf6 Qf4+ Ke7 Qe3+ Kd8
49  -46.39   06:28   3098M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 e4 Qc6+ Kg7 Qxe4 Rf1 Qd4+ Kf8 h5 Kg8 h6 Rf7 Qc4 Kf8 Qc8+ Ke7 Qc7+ Ke6 Qxa5 Rf8 Qb6+ Kd7 Qd4+ Ke6 Qe4+ Kd7 Qd5+ Ke7 Qc5+ Kf7 Qf2+ Kg8 Qxf8+ Kxf8
50  -46.39   06:33   3141M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 e4 Qc6+ Kg7 Qxe4 Rf1 Qd4+ Kf8 h5 Kg8 h6 Rf7 Qc4 a4 Qxa4 Re7 Qc4+ Kf8 Qc5 Ke8 Qxe7+ Kxe7
51  -46.07   07:51   3793M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 e4 Qxa5 Rf7 Qe5 Rf1 Qxe4 Kg7 Qe5+ Kf8 Kg3 Ra1 Kh2 Rb1 Qf5+ Ke7 Qc5+ Ke8 Qe3+ Kd8 Qd4+ Kc7 Qc5+ Kb7 Qg1 Rxg1 Kxg1
52  -46.39   08:50   4278M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rg7 Qxb5 Kh7 Qxe5 Ra7 Qc5 Ra6 Qb5 Ra7 Qb6 Re7 Qxa5 Re3+ Kh2 Re2+ Kg1 Re7 Qb5 Kg8 Qg5+ Kf8 Qxe7+ Kxe7 h5 Ke6 h6
53  -46.39   09:29   4599M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rg7 Qxb5 Kh7 Qxe5 Ra7 Qc5 Ra6 Qb5 Ra7 Qb6 Re7 Qxa5 Re3+ Kh2 Re2+ Kg1 Re7 Qb5 Kg8 Qg5+ Kf8 Qxe7+ Kxe7 h5 Ke6 h6 Kf6
54  -46.80   13:38   6781M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 a4 Qxe5 Rf1 Qe3+ Kg7 Qd4+ Kf8 Qxa4 Rb1 Kh2 Kf7 Qf4+ Ke7 Qd4 Ke8 Qg1 Rxg1 Kxg1 Kd7 h5 Kd8 h6 Kc8 h7
55  -49.49   17:47   9034M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rf4 Qxb5 Rf3+ Kg4 Rf4+ Kg3 a4 Qxe5 Rf1 Qh8+ Kg6 Qe8+ Kh7 Qe4+ Kh6 Qxa4 Kg7 Qg4+ Kh7 Kh2 Rf2+ Kh3 Rf6 Qh5+ Kg7 Qg5+ Rg6 Qe5+ Kf8 Qb8+ Kf7 Qf4+ Kg8 Qf5 Rg1 Qd5+ Kh7 Qd3+ Kg8 Qd8+ Kh7
56  -52.02   24:10  12494M  Kd4 Be3+ Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg4 Kh3 Rg7 Qxb5 Re7 Qc5 Re6 Qd5 Ra6 Qxe5 a4 Qh8+ Kg6 Qd4 Kh6 Qe4 Rf6 Qxa4 Rf3+ Kg4 Rf7 Kg3 Rg7+ Qg4 Rxg4+ Kxg4 Kg6 h5+ Kf6 h6 Kf7 h7 Kg6 h8=Q
Nodes: 15850336227
Nodes/second: 8805727
Best move: Kd4
Ponder move: Be3+
Parent - By Peter Grayson (****) [gb] Date 2015-10-05 22:04
Thanks for replying. I just installed Stockfish 051015 but am still getting same result on the dual Xeon and my older quad machines for example, with clean hash; 16 cores and 16 Gb hash ...

253: 21.Nd5 best?, Wei Yi
3qr3/1b1r1Q2/p2p1bp1/1p2p3/4k3/P7/1PPB2PP/4R2K b - - 0 1


Analysis by Stockfish 051015 64 POPCNT:

27...Kf5 28.Rf1+ Ke4 29.Re1+
  =  (0.00)   Depth: 7/7   00:00:00  1kN
27...Kf5 28.Rf1+ Ke4 29.Re1+
  =  (0.00)   Depth: 8/7   00:00:00  1kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 9/9   00:00:00  2kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 10/9   00:00:00  2kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 11/9   00:00:00  4kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 12/9   00:00:00  5kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 13/9   00:00:00  7kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 14/9   00:00:00  10kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 15/9   00:00:00  14kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 16/9   00:00:00  19kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 17/9   00:00:00  27kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 18/9   00:00:00  37kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 19/9   00:00:00  49kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 20/9   00:00:00  64kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 21/9   00:00:00  80kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 22/9   00:00:00  117kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 23/9   00:00:00  155kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 24/9   00:00:00  223kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 25/9   00:00:00  332kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 26/9   00:00:00  437kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 27/9   00:00:00  566kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 28/9   00:00:00  706kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 29/9   00:00:00  875kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 30/9   00:00:00  1129kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 31/9   00:00:00  1706kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 32/9   00:00:00  2096kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 33/9   00:00:00  3277kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 34/9   00:00:00  4596kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 35/9   00:00:00  5556kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 36/9   00:00:01  6489kN
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 37/9   00:00:01  21179kN, tb=15
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 38/9   00:00:01  24247kN, tb=16
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 39/9   00:00:02  26562kN, tb=16
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 40/9   00:00:02  35237kN, tb=170
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 41/9   00:00:02  40092kN, tb=170
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 42/9   00:00:03  60161kN, tb=2838
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 43/9   00:00:06  106MN, tb=14679
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 44/9   00:00:06  116MN, tb=14687
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 45/9   00:00:09  170MN, tb=14708
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 46/9   00:00:09  179MN, tb=14712
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 47/9   00:00:17  339MN, tb=105654
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 48/9   00:00:43  949MN, tb=593980
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 49/9   00:00:44  969MN, tb=593998
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 50/9   00:00:45  992MN, tb=594179
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 51/9   00:00:54  1216MN, tb=688166
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 52/9   00:01:33  2241MN, tb=1405078
27...Kd4 28.Be3+ Ke4
  =  (0.00)   Depth: 53/9   00:01:36  2298MN, tb=1405527

(Grayson, Newport, South Wales 05.10.2015)

So I'm flummoxed as to what is going on here! My machines do not support the later BMI engine so POPCNT version on Xeon and standard x64 version on quads. Same output with or without 5 man Syzygy bases and tried it in Arena, Fritz, HIARCS and Shredder GUIs.

Under same setup, Houdini 4 Pro + Syzygy has no problem with it ...

253: 21.Nd5 best?, Wei Yi
Same position

Analysis by Houdini 4 Pro x64:

27...Kf5 28.Rf1+ Ke4 29.Re1+ Kf5
  =  (0.00)   Depth: 7/14   00:00:00  1kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kf5
  =  (0.00)   Depth: 8/19   00:00:00  4kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 9/19   00:00:00  6kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 10/19   00:00:00  20kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 11/24   00:00:00  40kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 12/28   00:00:00  83kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 13/30   00:00:00  169kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 14/33   00:00:00  350kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 15/36   00:00:00  806kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 16/38   00:00:00  1528kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 17/40   00:00:00  3263kN
27...Kd4 28.Be3+ Ke4 29.Bd2+ Kd4
  =  (0.00)   Depth: 18/45   00:00:00  6642kN
27...Kd4 28.Be3+
  =  (0.07 --)   Depth: 19/52   00:00:00  12950kN
27...Kd4 28.Be3+
  =  (0.21 --)   Depth: 19/52   00:00:00  13186kN
27...Kd4 28.Be3+
  +/=  (0.54 --)   Depth: 19/55   00:00:01  15671kN
27...Kd4 28.Be3+
  +-  (1.73 --)   Depth: 19/55   00:00:01  16285kN
27...Kd4 28.Be3+
  +-  (5.20 --)   Depth: 19/72   00:00:01  31757kN
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 Rg6 42.Qxe5+ Kh6 43.h4 Kh7 44.h5 Rg8 45.Kh3 Rg1 46.Qe7+ Rg7 47.Qe4+ Kh6 48.Kh4 Rg8 49.Qe3+ Kh7 50.Qa7+ Rg7 51.Qxa6
  +-  (9.23)   Depth: 19/85   00:00:05  105MN
27...Kd4 28.Be3+
  +-  (9.61 --)   Depth: 20/85   00:00:05  107MN
27...Kd4 28.Be3+
  +-  (10.37 --)   Depth: 20/85   00:00:05  112MN
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 a5 42.Qd7 Kg6 43.Qxb5 e4 44.Qa6+ Kf7 45.Qc4+ Kf6 46.Qxe4 Re5 47.Qd4 Kf5 48.Kg3 Ke6 49.h4 Rd5 50.Qb6+ Ke7 51.Qc7+ Ke6 52.Qc6+ Rd6 53.Qe4+ Kf6 54.h5 Re6 55.Qf4+ Ke7 56.Qg5+ Kd6 57.Qxa5 Re3+ 58.Kg4
  +-  (11.01)   Depth: 20/85   00:00:06  129MN, tb=2
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 Rf5 42.Qxa6 e4 43.Qe6 Rf2+ 44.Kg3 Rf3+ 45.Kg2 Kg5 46.Qxe4 Rf5 47.h4+ Kf6 48.Kg3 Re5 49.Qc6+ Kf5 50.Qc8+ Kf6 51.Qd7 Rf5 52.Qc6+ Kg7 53.Qb6 Kf7 54.Qa6 Kg7 55.Qa7+ Rf7 56.Qc5 Rb7 57.Qc6 Rf7 58.Qxb5 Kh6 59.Qe5 Rf1 60.a4 Rg1+ 61.Kf3
  +-  (11.27)   Depth: 21/85   00:00:06  149MN, tb=5
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 a5 42.Qd7 Kg6 43.Qxb5 e4 44.Qa6+ Kf7 45.Qc4+ Kf6 46.Qxe4 Re5 47.Qd4 Kf5 48.Kg3 Ke6 49.h4 Rd5 50.Qb6+ Ke7 51.Qc7+ Ke6 52.Qc6+ Rd6 53.Qe4+ Kf6 54.h5 Re6 55.Qf4+ Ke7 56.Qg5+ Kf7 57.Qxa5 Kf6 58.Kf4 Re2 59.Qg5+ Kf7 60.h6
  +-  (11.64)   Depth: 22/85   00:00:07  185MN, tb=14
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 e4 42.Qxa6 Rf5 43.Qe6 Rf2+ 44.Kg3 Rf3+ 45.Kg2 Kg5 46.Qxe4 Rf5 47.h4+ Kf6 48.Kg3 Re5 49.Qc6+ Kf5 50.Qb6 Re7 51.Qc5+ Re5 52.Qc8+ Kg6 53.Kf4 Re7 54.Qa6+ Kg7 55.Qxb5 Kh7 56.Qd5 Ra7 57.h5 Rg7 58.a4 Kh6 59.a5
  +-  (12.07)   Depth: 23/85   00:00:09  250MN, tb=55
27...Kd4 28.Be3+
  +-  (12.57 --)   Depth: 24/85   00:00:10  285MN, tb=91
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 e4 42.Qxa6 Rf5 43.Qe6 Rf2+ 44.Kg3 Rf3+ 45.Kg2 Kg5 46.Qxe4 Rf5 47.h4+ Kf6 48.Kg3 Re5 49.Qc6+ Kf5 50.Qb6 Re7 51.Qxb5+ Re5 52.Qd7+ Re6 53.Qd5+ Kf6 54.Qc5 Re8 55.Qd4+ Ke6 56.Qe4+ Kf7 57.Qf5+ Kg7 58.h5 Re1 59.Qd7+ Kf6 60.Qd6+ Re6 61.Qd4+ Kf7 62.Qc4 Ke7 63.Qc5+ Kf7 64.Qb5 Rf6 65.Qe5 Re6 66.Qb5 Rf6
  +-  (12.57)   Depth: 24/85   00:00:12  343MN, tb=126
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 a5 42.Qd7 Kg6 43.Qxb5 e4 44.Qa6+ Kf7 45.Qc4+ Kf6 46.Qxe4 Re5 47.Qd4 Kf5 48.Kg3 Re6 49.Qd5+ Kf6 50.Qxa5 Re5 51.Qc3 Kf5 52.Qd3+ Kf6 53.h4 Kf7 54.Qc4+ Re6 55.Qd5 Ke7 56.h5 Rh6 57.Qg5+ Rf6 58.h6 Ke6 59.h7
  +-  (12.55)   Depth: 25/85   00:00:17  524MN, tb=195
27...Kd4 28.Be3+
  +-  (13.07 --)   Depth: 26/85   00:00:18  545MN, tb=202
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 a5 42.Qd7 Kg6 43.Qxb5 e4 44.Qa6+ Kf7 45.Qc4+ Kf6 46.Qxe4 Re5 47.Qd4 Kf5 48.Kg3 Re6 49.Qd5+ Kf6 50.Qxa5 Re5 51.Qc3 Kf5 52.h4 Ke6 53.Qc4+ Kd7 54.h5 Re3+ 55.Kh2 Re6 56.Qd5+ Ke7 57.Kg3 Rh6 58.Kf4 Re6 59.Qc5+ Kf7 60.Qb5 Rd6 61.Kg4 Rf6 62.Kg5 Rd6 63.Qb7+ Ke6 64.h6 Rd8 65.Qe4+ Kd6 66.Qd4+ Kc7 67.Qc5+
  +-  (12.97)   Depth: 26/85   00:00:24  765MN, tb=288
27...Kd4 28.Be3+ Ke4 29.Qb3 Kf5 30.Rf1+ Kg4 31.Qd3 Rg7 32.h3+ Kh4 33.Qe2 Qd7 34.Kh2 Bxg2 35.Qxg2 Qf5 36.Rxf5 gxf5 37.Qf2+ Kh5 38.Qxf5+ Bg5 39.Bxg5 Rf8 40.Qxf8 Rxg5 41.Qxd6 a5 42.Qd7 Kg6 43.Qxb5 e4 44.Qa6+ Kf7 45.Qc4+ Kf6 46.Qxe4 Rg8 47.Qd4+ Kg6 48.Qg4+ Kf7 49.Qf5+ Ke7 50.Qe5+ Kf7 51.Qd5+ Kg7 52.Qxa5 Re8 53.h4 Re6 54.Qg5+ Kh8 55.Qd5 Re2+ 56.Kg3 Re1 57.Qb5 Re7 58.Qb4 Rg7+ 59.Kh2 Rg6 60.Qc3+ Kg8 61.Qc8+ Kf7 62.Qd7+ Kf6 63.Qd6+ Kf7 64.Qc7+ Ke8 65.Qc8+ Ke7 66.Qb7+ Kf8 67.Qb4+ Kf7 68.Qc4+ Ke7 69.Qb5 Re6 70.Qc5+ Kf7 71.h5 Kf6 72.Qd5 Re5 73.Qd4 Ke6 74.h6 Rh5+ 75.Kg3 Rg5+ 76.Kh4 Rg6 77.h7 Rh6+ 78.Kg5 Rxh7 79.Qe4+
  +-  (13.47)   Depth: 27/85   00:00:44  1561MN, tb=1307
27...Kd4 28.Be3+
  +-  (14.03 --)   Depth: 28/105   00:00:47  1652MN, tb=1883
27...Kd4 28.Be3+
  +-  (15.15 --)   Depth: 28/105   00:00:51  1805MN, tb=6965

(Grayson, Newport, South Wales 05.10.2015)

Peter
Parent - By user923005 (****) [us] Date 2015-10-05 21:12
Using the latest bleeding edge stockfish, this position is seen instantly as lost for black, and even resolves to black being checkmated:

Searching:
3qr3/1b1r1Q2/p2p1bp1/1p2p3/3k4/P3B3/1PP3PP/4R2K b - - 0 1

infinite: 0 ponder: 0 time: 0 increment: 0 moves to go: 0

1  -53.37   00:00      26  Ke4
2  -53.37   00:00      54  Ke4 Qb3
3  -53.37   00:00      99  Ke4 Qb3 Kf5
4  -53.37   00:00     158  Ke4 Qb3 Kf5 Rf1+ Kg4
5  -53.37   00:00     226  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3
6   +0.00   00:00    3340  Ke4 Bd2+ Kd4 Be3+
7   +0.00   00:00    3969  Ke4 Bd2+ Kd4 Be3+
8   +0.00   00:00    4833  Ke4 Bd2+ Kd4 Be3+
9   +0.00   00:00    6360  Ke4 Bd2+ Kd4 Be3+
10  -52.59   00:00    8654  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Qg2+ Kxg2
11  -46.90   00:00   19728  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Qg2+ Kxg2 Bg5 Qe2+ Kh4
12  -50.48   00:00   29019  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Rg7 Rxf6 Rh8 Qe2+ Kh4
13  -49.55   00:00   49130  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Bg5 Qe2+ Kh4 Bf2+ Kh3 Be1 Qa7+ Kh1
14  -49.55   00:00   50528  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Bg5 Qe2+ Kh4 Bf2+ Kh3 Be1 Qa7+ Kh1 Qg1+ Kxg1
15  -49.55   00:00   52199  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Bg5 Qe2+ Kh4 Bf2+ Kh3 Be1 Qa7+ Kh1 Qg1+ Kxg1
16  -53.37   00:00   56151  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Bg5 Qe2+ Kh4 Bf2+ Kh3 Be1 Qa7+ Kh1 Qg1+ Kxg1 Be3+ Qxe3+ Kg4 Qf3+ Kg5 Bd2+ Kh4
17  -54.07   00:00   66238  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5
18  -51.29   00:00  163318  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Bxg2+ Kxg2 Qa8+ Kg1 Rg8 Rxf6 a5 Qxb5 Rc7 Qe2+ Kh4 Qf2+ Kh5 Qg3 Qh1+ Kxh1
19  -43.79   00:00  421783  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rg2+ Kxg2
20  -43.79   00:00  455106  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8
21  -43.79   00:00  495666  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5
22  -43.79   00:00  557716  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 h3+ Kh4 Qe2 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6
23  -43.91   00:00   1580K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qd1+ Kh4 Qe1+ Kh5 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5
24  -43.91   00:00   1681K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qd1+ Kh4 Qe1+ Kh5 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6
25  -44.57   00:00   4246K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Kg7 hxg5 Kf7 Qxb5
26  -42.28   00:00   6261K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Rg2+ Kxg2
27  -43.79   00:00   6453K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg2+ Kxg2
28  -43.79   00:00   6672K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rg2+ Kxg2
29  -44.57   00:01   6961K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Kg7 hxg5 Kf7
30  -44.57   00:01   7305K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Kg7 hxg5 Kf7 Qxb5
31  -43.02   00:01  12543K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kg7 Qxh5
32  -43.02   00:02  20000K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 e4 b6
33  -43.02   00:02  20618K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4
34  -43.02   00:02  21324K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4
35  -43.02   00:02  22249K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5
36  -43.02   00:03  23539K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 e4
37  -43.02   00:03  25174K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 e4 b6
38  -51.80   00:03  25597K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 Ke6 b6 Kf6
39  -51.67   00:03  25905K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 Ke6 b6 e4 b7
40  -51.67   00:06  50109K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 Ke6 b6 e4 b7 a3
41  -39.62   00:08  63818K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kg7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 e4 b6 e3 b7 Kg7 b8=Q
42  -51.67   00:09  75917K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qd7+ Kh6 Qe6+ Kh7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 Ke6 b6 e4 b7 a3
43  -51.67   00:09  76282K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qd7+ Kh6 Qe6+ Kh7 Qe7+ Kg6 Qe8+ Kf6 Qxh5 b4 axb4 a4 b5 Ke6 b6 e4 b7 a3 bxa3
44  -53.00   00:11  89701K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qe7+ Kg6 Qe8+ Kh6 Kg3 e4 Kg4 Rc5 Qf8+ Kg6 Qxc5 Kf7 Qxb5 Ke7 Qxa5 Kd6 Qf5 Kc7 Qxe4
45  -52.92   00:12  97804K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qe7+ Kg6 Qe8+ Kh6 Kg3 e4 Kg4 Rc5 Qf8+ Kg6 Qxc5 Kf7 Qxb5 Ke7 Qxa5 Kd6 Qf5 Kc7 Qxe4 Kb6
46  -52.92   00:14 110225K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qe7+ Kg6 Qe8+ Kh6 Kg3 e4 Kg4 Rc5 Qf8+ Kg6 Qxc5 Kf7 Qxb5 Ke7 Qxa5 Kd6 Qf5 Kc7 Qxe4 Kb6 Qb4+ Ka6
47  -52.96   00:14 111706K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qe7+ Kg6 Qe8+ Kh6 Kg3 e4 Kg4 Rc5 Qf8+ Kg6 Qxc5 Kf7 Qxb5 Ke7 Qxa5 Kd6 Qf5 Kc7 Qxe4 Kb6 Qb4+ Ka6 h5
48  -53.00   00:17 139094K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qe7+ Kg6 Qe8+ Kh6 Kg3 e4 Qxe4 b4 Qe6+ Kg7 Qe7+ Kh6 Kg4 Rb5 Qe6+ Kg7 Qd7+ Kf6 Qxb5 b3 Qxa5 Ke6 cxb3 Kd6 Qb6+ Kd5 Qb5+ Ke4
49  -53.03   00:18 141974K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 a5 Qd3 Kh6 h4 Rh5 Qd6+ Kh7 Qe7+ Kg6 Qe8+ Kh6 Kg3 e4 Qxe4 b4 Qe6+ Kg7 Qe7+ Kh6 Qf8+ Kh7 Qf7+ Kh6 Kg4 Rb5 Qe6+ Kg7 Qd7+ Kf6 Qxb5 b3 Qxa5 Ke6 cxb3 Kd6 Qb5
50  -52.38   00:24 199697K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Kg5 Kg3 Rf6 h4+ Kf5 Qxf6+ Kxf6 Kg4 Ke6 Kf3 Kd5 Kf2 e4 Ke3 Ke6 b3 Kf5 b4 Kg4 Kxe4 Kg3 Ke3 Kh3 h5 Kg2 h6 Kh3
51  -53.15   00:26 211858K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Kg5 Kg3 Rf6 h4+ Kf5 Qxf6+ Kxf6 Kg4 Ke6 h5 Kf6 h6 Kg6 Kf3 e4+ Ke3 Kh7 Kf4 e3 Kxe3 Kg8 h7+ Kh8 Kd4 b4 axb4 Kg7 h8=Q+ Kg6
52  -54.29   00:49 425542K  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Kg5 Kg3 Rf6 h4+ Kf5 Qxf6+ Kxf6 Kg4 e4 Kf4 e3 Kxe3 Kg6 h5+ Kf7 Kf4 Ke6 Ke4 Kd6 h6 Kc5 h7 Kb6 h8=Q Ka6 Qe8 b4 axb4 Ka7
53  -58.55   02:38   1457M  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Kg5 Kg3 Rf1 Qe6 Rg1+ Kh2 Ra1 Qxe5+ Kg6 Qxb5 Kf7 h4 Re1 Qa5 Re7 Qd5+ Kg7 Qd4+ Kf7 Qc4+ Kg7 Qd3 Rf7 Qd4+ Kf8 h5 Ke8 Qe5+ Kd7 Qd5+ Ke7 Qxf7+ Kxf7 h6 Kf8 h7 Kf7
54 -122.99   07:49   4481M  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Kg5 Kg3 Rf1 Qe6 Rg1+ Kh2 Ra1 Qxe5+ Kg6 Qxb5 Kf6 h4 Ke6 Qb6+ Kf5 Qg1 Kf6 Qxa1 Ke7 Qe1+ Kd7 Qd2+ Kc8 h5 Kc7 Qd7+ Kxd7 h6 Kd6 h7 Kc6 h8=Q Kb7 Qh7+ Kc6 Qg6+ Kd5
55 -123.01   10:03   5768M  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Rf2+ Kg3 Rf1 Qxb5 Re1 Qb4 Rf1 Qg4+ Kh6 Qe6+ Kh7 Qxe5 Kg8 Qd5+ Kf8 Qc5+ Kg7 Kh2 Rb1 Qg1+ Rxg1 Kxg1 Kg6 b4 Kh6 Kh2 Kg5 b5 Kf4 b6 Ke5 b7 Kd4 b8=Q Kc5 Qd6+ Kb5
56   -#100   14:24   8158M  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Rf2+ Kg3 Rf1 Qxb5 Re1 Qb4 Rf1 Qg4+ Kh6 Qe6+ Kh7 Qxe5 Kg8 Qd5+ Kg7 Qd4+ Kh6 h4 Rf7 Qh8+ Kg6 Qg8+ Rg7 Qxg7+ Kxg7 h5 Kh6 Kf3 Kg5 h6 Kf6 Kg3 Ke5 h7 Kd4 h8=Q+ Kd5 Qa8+ Kd6 Qc6+ Ke7
57   -#100   16:44   9314M  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Rf2+ Kg3 Rf1 Qxb5 Re1 Qb4 Rf1 Qg4+ Kh6 Qe6+ Kh7 Qxe5 Kg8 Qd5+ Kg7 Qd4+ Kh6 h4 Rf7 Qh8+ Kg6 Qg8+ Rg7 Qxg7+ Kxg7 h5 Kh6 Kf2 Kg7 h6+ Kh7 Kg3 Kg6 h7 Kf7 h8=Q Ke6 Qc8+ Ke5 Qc5+ Ke4 Qd4+ Kxd4
58    -#98   21:59  11936M  Ke4 Qb3 Kf5 Rf1+ Kg4 Qd3 Rg7 Qe2+ Kh4 h3 Qd7 Kh2 Bxg2 Qxg2 Qf5 Rxf5 gxf5 Qf2+ Kh5 Qxf5+ Bg5 Bxg5 Rf8 Qxf8 Rxg5 Qxd6 Rf5 Qxa6 Rf2+ Kg3 Rf1 Qxb5 Re1 Qb4 Rf1 Qe4 Rg1+ Kh2 Ra1 Qxe5+ Kg6 h4 Kf7 Qc5 Kg8 Qg1+ Rxg1 Kxg1 Kg7 h5 Kh6 Kf2 Kg7 h6+ Kh7 Kg3 Kg6 h7 Kf7 h8=Q Ke6 Qe5+ Kd7 Qd6+ Kc8
Nodes: 16210810334
Nodes/second: 9006000
Best move: Ke4
Ponder move: Qb3
Parent - - By Peter Grayson (****) [gb] Date 2015-10-04 19:04
The reason so many engines do not choose 21.Nd5 is because Black's reply 21..Nxd5 is a blunder.

White has much more work to do after 21..Bxd5 in which case there may be marginally better moves for white than the game's 21st move. No need to run this on fast hardware because even on my now aging quad Stockfish shows a winning advantage for White after 21..Nxd5? but less than 0.8 for 21..Bxd5.

Faster hardware shows 21..Bd5 looks a better defence for Black

253: 21.Nd5 best?, Wei Yi
3qr1k1/1b1rbp2/p2p1np1/1p1Np3/4P3/P2BB2Q/1PP3PP/4RR1K b - - 0 1


Analysis by Stockfish 031015 64 POPCNT, 16 CPUs, 32768 Mb hash:

21...Bxd5 22.exd5 Rb7 23.Qf3 Kg7 24.Re2 Rh8 25.g4
  +/-  (0.87)   Depth: 7/7   00:00:00  1kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2
  +/-  (0.87)   Depth: 8/8   00:00:00  2kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qc8 25.Bd2 Bd8
  +/-  (0.77)   Depth: 9/10   00:00:00  4kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.Qf2 Qd7 25.c4 Bd8 26.Bg5 Nh5 27.Bh6 bxc4 28.Bxc4
  +/-  (0.75)   Depth: 10/13   00:00:00  11kN
21...Bxd5 22.exd5 Rb7 23.c3 Qd7 24.Bf5 gxf5 25.Rxf5 Nh7 26.Qg3+ Kh8 27.Rxf7 Rg8
  +/=  (0.67)   Depth: 11/16   00:00:00  35kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.g5 Nh5 26.Rf2 Bd8 27.Ref1 Kg8 28.c3
  +/=  (0.66)   Depth: 12/17   00:00:00  67kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.Bd2 Qd7 25.c4 Bd8 26.b4 Kg8 27.Bh6 bxc4 28.Bxc4
  +/-  (0.76)   Depth: 13/18   00:00:00  92kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Bb6 28.Bxb6 Rxb6 29.Qh4 Qe7
  +/=  (0.65)   Depth: 14/22   00:00:00  180kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Kg8 28.h4 Nf8 29.Bg4 Qe7 30.c3 Bb6 31.Bxb6 Rxb6 32.Qe3 Rb7 33.h5 gxh5
  +/-  (0.71)   Depth: 15/22   00:00:00  219kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Kg8 28.h4 Bb6 29.Bxb6 Rxb6 30.Bd3 Rb7 31.c3
  +/-  (0.73)   Depth: 16/22   00:00:00  244kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Bb6 28.Bd2 Rg8 29.b3 Rg7 30.Bg4 Qc7 31.Qd3 Nf8 32.c4 bxc4 33.Qxc4 Rh7
  +/=  (0.70)   Depth: 17/24   00:00:00  497kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.h4 Bb6 29.Bxb6 Rxb6 30.c3 Nf8 31.Qf2 Rb7 32.Qf6+ Kg8
  +/-  (0.78)   Depth: 18/25   00:00:00  547kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.h4 Bb6 29.Bxb6 Rxb6 30.c3 Nf8 31.Qf2 Rb7 32.Qf6+ Kg8
  +/-  (0.78)   Depth: 19/25   00:00:00  632kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Kg8 28.h4 Bb6 29.Bxb6 Rxb6 30.Bd3 Rf8 31.c3 Rbb8 32.Kg2 Qc8 33.h5 Qb7
  +/-  (0.77)   Depth: 20/26   00:00:00  847kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Kg8 28.h4 Bb6 29.Bxb6 Rxb6 30.Bd3 Rf8 31.c3 Rbb8 32.Kg2 Qc8 33.Be4 Rb7 34.Rf2 a5
  +/-  (0.77)   Depth: 21/27   00:00:00  1264kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh5 27.Qg2 Ng7 28.Bg4 Qc7 29.Rf2 Kg8 30.Ref1 e4 31.Rxf7 Qxf7 32.Rxf7 Rxf7 33.Qh3 Nf5 34.Bxf5 Rxf5
  +/-  (0.81)   Depth: 22/29   00:00:00  1666kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.h4 Bb6 29.Bxb6 Rxb6 30.c3 Rb7 31.Bd3 Rf8 32.Re2 Rbb8 33.Ref2 Qb7 34.Be4 Qe7 35.Bc2
  +/-  (0.85)   Depth: 23/32   00:00:00  2328kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.h4 Rg8 29.Bd3 f5 30.h5 Nxg5 31.hxg6 Rxg6 32.Qh2+ Qh7 33.Bxf5 Qxh2+ 34.Kxh2 Rh6+ 35.Kg2
  +/-  (0.79)   Depth: 24/37   00:00:00  4227kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.h4 Rg8 29.Qg2 Bb6 30.Bd2 Nf8 31.h5 gxh5 32.Bxh5 Rg7 33.Qg4 Rh7 34.Kg2 Kg8
  +/-  (0.78)   Depth: 25/37   00:00:01  7192kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.h4 Rg8 29.Qg2 Bb6 30.Bxb6 Rxb6 31.Qf3 Rf8 32.Qg3 Rbb8 33.c3 e4 34.Kg2 f5 35.gxf6 Rxf6 36.Rxf6
  +/-  (0.76)   Depth: 26/37   00:00:01  9322kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg2 Bb6 28.Bxb6 Rxb6 29.c3 Kg7 30.Rf2 Rh8 31.Ref1 Rb7 32.Kg1 Qd8 33.h4 Kg8 34.Bd3 Nf8 35.Qe4 Rh7 36.Kg2 Qd7
  +/-  (0.81)   Depth: 27/37   00:00:02  24806kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg2 Bb6 28.Bxb6 Rxb6 29.c3 Kg7 30.Rf2 Rh8 31.Ref1 Rb7 32.Kg1 Qd8 33.h4 Kg8 34.Bd3 Nf8 35.Qe4 Rh7 36.Kg2 Qe7 37.c4 bxc4 38.Qxc4
  +/-  (0.81)   Depth: 28/37   00:00:02  27651kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg2 Bb6 28.Bxb6 Rxb6 29.c3 Kg7 30.Rf2 Rh8 31.Ref1 Rb7 32.Kg1 Qd8 33.h4 Kg8 34.Bd3 Nf8 35.Qe4 Rh7 36.Kg2 Qe7 37.c4 bxc4 38.Qxc4
  +/-  (0.75)   Depth: 29/38   00:00:02  34337kN
21...Bxd5
  +/=  (0.68 ++)   Depth: 30/38   00:00:03  52837kN
21...Bxd5 22.exd5
  +/-  (0.75 --)   Depth: 30/39   00:00:05  87493kN
21...Bxd5
  +/=  (0.68 ++)   Depth: 30/39   00:00:06  97790kN
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.b4 Qc8 25.a4 Bd8 26.Bg5 Nh5 27.Bd2 Nf6 28.h3 Qc7 29.axb5 axb5 30.Qe2 Nh5 31.Qg4 Nf6 32.Qg5 Ng8 33.Qg3 Nf6 34.Qh4+ Nh5 35.Qf2 Nf6 36.g4 Nxd5
  +/=  (0.69)   Depth: 30/39   00:00:06  104MN
21...Bxd5 22.exd5
  +/-  (0.75 --)   Depth: 31/39   00:00:07  131MN
21...Bxd5 22.exd5
  +/-  (0.81 --)   Depth: 31/39   00:00:08  136MN
21...Bxd5
  +/-  (0.75 ++)   Depth: 31/39   00:00:08  143MN
21...Bxd5 22.exd5
  +/-  (0.83 --)   Depth: 31/43   00:00:09  160MN, tb=2
21...Bxd5
  +/-  (0.72 ++)   Depth: 31/43   00:00:10  174MN, tb=2
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.Qg2 Nh7 27.g5 Qe7 28.h4 Rg8 29.c3 Bb6 30.Bd2 Nf8 31.Qg4 Rg7 32.Kg2 Rh7 33.a4 bxa4 34.Bxa6 Bc5 35.Bxb7 Qxb7 36.Re2 a3 37.bxa3
  +/-  (0.74)   Depth: 31/46   00:00:11  191MN, tb=5
21...Bxd5
  +/=  (0.68 ++)   Depth: 32/46   00:00:13  224MN, tb=5
21...Bxd5 22.exd5
  +/-  (0.74 --)   Depth: 32/46   00:00:13  235MN, tb=5
21...Bxd5
  +/=  (0.68 ++)   Depth: 32/46   00:00:14  242MN, tb=5
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Rg1 Kg7 28.Ref1 Rh8 29.Rg3 Kg8 30.h4 Nf8 31.Qe4 Rh7 32.Kg2 Bb6 33.Bxb6 Rxb6 34.Bd3 Qe7 35.Rgf3 Rb8 36.b4 Rc8 37.c4 Qb7 38.Rf6 Qd7 39.R1f3 bxc4
  +/=  (0.65)   Depth: 32/46   00:00:16  283MN, tb=5
21...Bxd5 22.exd5
  +/-  (0.72 --)   Depth: 33/46   00:00:18  320MN, tb=5
21...Bxd5
  +/=  (0.65 ++)   Depth: 33/46   00:00:21  381MN, tb=5
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Rg1 Kg7 28.Ref1 Rh8 29.Rg3 Kg8 30.h4 Nf8 31.Qe4 Rh7 32.Kg2 Bb6 33.Bxb6 Rxb6 34.Rgf3 Qe7 35.b4 Rb8 36.Bd3 Qc7 37.c4 bxc4 38.Bxc4
  +/=  (0.59)   Depth: 33/46   00:00:27  496MN, tb=9
21...Bxd5 22.exd5
  +/=  (0.65 --)   Depth: 34/46   00:00:29  537MN, tb=9
21...Bxd5 22.exd5
  +/-  (0.72 --)   Depth: 34/46   00:00:30  548MN, tb=22
21...Bxd5 22.exd5
  +/-  (0.81 --)   Depth: 34/46   00:00:31  572MN, tb=22
21...Bxd5
  +/-  (0.73 ++)   Depth: 34/46   00:00:35  644MN, tb=33
21...Bxd5 22.exd5
  +/-  (0.84 --)   Depth: 34/49   00:00:42  800MN, tb=33
21...Bxd5
  +/=  (0.68 ++)   Depth: 34/55   00:00:58  1104MN, tb=37
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qc8 25.Bd2 Bd8 26.g5 Nh5 27.Re4 Qd7 28.Rh4 Kg7 29.Rxh5 gxh5 30.g6 f6 31.Rg1 Rh8 32.h3 Bb6 33.Rf1 Bd8 34.Bf5 Qc7 35.Be4 Qd7 36.Kh2 Qg4 37.Qe3 Qc8 38.Bd3 Qc7 39.Qf2 Qe7 40.Qf5 Qd7 41.Qf2 Kf8 42.Bg5
  +/=  (0.68)   Depth: 34/55   00:01:00  1126MN, tb=37
21...Bxd5 22.exd5
  +/-  (0.75 --)   Depth: 35/55   00:01:06  1247MN, tb=37
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qc8 25.Bd2 Bd8 26.g5 Nh5 27.Re4 Qd7 28.Rh4 Kg7 29.Rxh5 gxh5 30.Rg1 Rh8 31.g6 f6 32.h3 Bb6 33.Rf1 Bd8 34.Bf5 Qe7 35.Kh2 Rc7 36.Bd3 Qd7 37.Kg2 Qe7 38.Kh1 Rb7 39.Bf5 Kf8 40.Be6 Bb6
  +/-  (0.75)   Depth: 35/55   00:01:10  1330MN, tb=39
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qc8 25.Bd2 Bd8 26.g5 Nh5 27.Re4 Qd7 28.Rh4 Kg7 29.Rxh5 gxh5 30.Rg1 Rh8 31.g6 f6 32.h3 Bb6 33.Rf1 Bd8 34.Bf5 Qe7 35.Kh2 Rc7 36.Bd3 Qd7 37.Rg1 Qe8 38.Bb4 Qe7 39.Rf1 Rc4 40.Bxc4 bxc4 41.Qe4 Rh6
  +/-  (0.74)   Depth: 36/55   00:01:23  1585MN, tb=75
21...Bxd5 22.exd5
  +/-  (0.81 --)   Depth: 37/55   00:01:37  1868MN, tb=108
21...Bxd5
  +/-  (0.74 ++)   Depth: 37/55   00:01:49  2113MN, tb=121
21...Bxd5 22.exd5
  +/-  (0.81 --)   Depth: 37/55   00:01:50  2131MN, tb=121
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Rg8 28.Bd3 Rb8 29.Re2 Qb7 30.Be4 Rc8 31.Rg2 Rg7 32.Qf3 Bb6 33.Bxb6 Qxb6 34.h4 Rf8 35.Qd3 Rb8 36.c3 Qc7 37.h5 gxh5 38.g6 fxg6 39.Rxg6 Rxg6 40.Bxg6 Nf8 41.Bxh5
  +/-  (0.74)   Depth: 37/55   00:02:08  2491MN, tb=122
21...Bxd5
  +/=  (0.68 ++)   Depth: 38/55   00:02:43  3210MN, tb=269
21...Bxd5 22.exd5
  +/-  (0.74 --)   Depth: 38/55   00:02:48  3312MN, tb=630
21...Bxd5 22.exd5
  +/-  (0.84 --)   Depth: 38/55   00:02:56  3455MN, tb=632
21...Bxd5
  +/-  (0.76 ++)   Depth: 38/55   00:02:59  3527MN, tb=635
21...Bxd5 22.exd5
  +/-  (0.87 --)   Depth: 38/55   00:03:09  3709MN, tb=641
21...Bxd5
  +/-  (0.71 ++)   Depth: 38/56   00:03:14  3806MN, tb=655
21...Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qc8 25.Bd2 Bd8 26.g5 Nh5 27.Re4 Qd7 28.Rh4 Kg7 29.Rxh5 gxh5 30.Bf5 Qc7 31.g6 f6 32.Be1 Rh8 33.Be4 h4 34.h3 Qe7 35.Bd2 Ra7 36.Rg1 Bb6 37.Rg4 Rc7 38.Bd3 Qe8 39.Qf5 Qg8 40.Qe4 Re7 41.Qf3 Qe8 42.Bb4
  +/-  (0.83)   Depth: 38/57   00:03:21  3948MN, tb=660

(Grayson, Newport, South Wales 04.10.2015)
Parent - - By user923005 (****) [us] Date 2015-10-05 21:42
40 ply search shows -80 centipawns for black (pretty similar to the outcome after the other good moves have been played).

Searching:
3qr1k1/1b1rbp2/p2p1np1/1p1Np3/4P3/P2BB2Q/1PP3PP/4RR1K b - - 0 1

infinite: 0 ponder: 0 time: 0 increment: 0 moves to go: 0

1   -0.67   00:00      49  Nxd5 exd5 Bxd5
2   -0.67   00:00      92  Nxd5 exd5
3   -0.45   00:00     171  Bxd5 exd5 e4
4   +1.15   00:00     262  Bxd5 Rxf6 Bxf6 exd5
5   +1.29   00:00     479  Bxd5 exd5 e4 Bxe4 Nxe4
6   +0.34   00:00    1170  Bxd5 exd5 e4 Bxe4 Nxe4 Qf3
7   +1.16   00:00    2140  Bxd5 exd5 e4 Bg5 exd3 Rxe7 Rdxe7
8   -0.74   00:00    6709  Nxd5 Rxf7 Kxf7 Qh7+ Ke6 exd5+ Kxd5 Qxg6 Rf8 Be4+ Kc4
9   -0.03   00:00   13620  Nxd5 Rxf7 Kxf7 Qh7+ Ke6 exd5+ Kxd5 c4+ Kc6 cxb5+ Kc7 Rc1+ Kb8 bxa6
10   +0.00   00:00   38618  Nxd5 Rxf7 Kxf7 Qh7+ Ke6 Qh3+ Kf7
11   +0.00   00:00   49897  Nxd5 Rxf7 Kxf7 Qh7+ Ke6 Qh3+ Kf7
12   +0.00   00:00   56975  Nxd5 Rxf7 Kxf7 Qh7+ Ke6 Qh3+ Kf7
13   +0.00   00:00   72269  Nxd5 Rxf7 Kxf7 Qh7+ Ke6 Qh3+ Kf7
14   -0.92   00:00  484700  Bxd5 exd5 Qc8 Bg5 Nh7 Bd2 Bg5 Bxg5 Nxg5 Qh6 e4 Be2 Nh7 Bg4
15   -1.20   00:00   1179K  Bxd5 exd5 Rf8 Bh6 Rc7 c3 Qa8 Bxf8 Qxf8 Bc2 Qc8 Qg3 Bd8 h3 Qa8 Bxg6 fxg6 Qxg6+ Rg7
16   -1.14   00:00   1454K  Bxd5 exd5 Rf8 Bh6 Rc7 c3 Qc8 Bf5 Qa8 Bxf8 Qxf8 Bc2 Qc8 Qg3 Bd8 Bd3
17   -1.19   00:00   2773K  Bxd5 exd5 Rf8 Bh6 Rc7 c3 Qc8 Qf3 Qa8 Bc2 Rc5 Bb3 Qc8 h3 a5 Bxf8 Qxf8 Qd3
18   -1.12   00:00   3074K  Bxd5 exd5 Rf8 Bh6 Rc7 c3 Qc8 Qf3 Qa8 Bc2 Rc5 Bxf8 Qxf8 Rd1 Qc8 h3 Qa8 g4
19   -1.19   00:00   3792K  Bxd5 exd5 Rf8 Bh6 Rc7 c3 Qc8 Qf3 Qa8 Bc2 Rc5 Bg5 Nxd5 Bh6 f5 Qg3 Qe8 Rxf5 Rxf5 Bxf5
20   -0.76   00:03  21051K  Bxd5 exd5 Rb7 Qf3 Kh8 Bc1 Qc8 Bg5 Nh7 Bxe7 Rexe7 g4 Qd8 Qh3 Kg8 Qh6 Qf8 Qxf8+ Nxf8 Rf6 Red7 c3 a5
21   -0.69   00:04  27133K  Bxd5 exd5 Rb7 Qf3 Kh8 Bc1 Qc8 a4 Bd8 axb5 axb5 Bg5 Nh7 Bd2 Nf6 Ba5 Bxa5 Qxf6+ Kg8 Ra1 e4 Rxa5 exd3 cxd3
22   -0.80   00:05  32687K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 Bd3 Kg8 c3 Rb7 h4 Rc7 Qf3 Nf8 Kg2 Qd8
23   -0.83   00:05  35091K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 Bd3 Rb7 c3 Kg8 h4 Qd8 Qg3 a5 Kg2 a4 Qe3 Nf8 Qf3 Qd7
24   -0.81   00:07  47404K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 e4 Rf4 Qe7 Bxb5 Reb8 Rfxe4 Qxg5 Re8+ Rxe8 Rxe8+ Kg7 Qxg5 Nxg5
25   -0.82   00:08  51285K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 Qe7 h4 Rb7 Bd3 Nf8 Rf2 Kg8 Be4 Qc7 h5 gxh5 g6 fxg6
26   -0.76   00:10  62620K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 a5 h4 Rb7 Rf2 Ra8 Ref1 Qe8 Qe4 b4 axb4 axb4 cxb4 Ra4
27   -0.75   00:13  81969K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 a5 Bd3 Rb7 Rf2 b4 axb4 axb4 c4 Ra7 Ref1 Re7 h4 Qe8 Qe4 Nf8 Kg2 Nd7
28   -0.75   00:16 105610K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 a5 Bd3 Rb7 Rf2 b4 axb4 axb4 c4 Ra7 Ref1 Re7 h4 Qe8 Qe4 Nf8 Kg2 Nd7
29   -0.79   00:19 122087K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 a5 Bd3 Rb7 Rf2 b4 axb4 axb4 c4 Ra7 Ref1 Re7 h4 Qe8 Be4 Qc8 b3 Rec7 Bd3
30   -0.86   00:23 150447K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 Qg2 Nh7 g5 Bb6 Bxb6 Rxb6 c3 a5 Bd3 Rb7 Rf2 b4 axb4 axb4 c4 Ra7 Ref1 Re7 h4 Qe8 Be4 Qc8 b3
31   -0.64   00:44 288357K  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Bd2 Bd8 g5 Nh5 Re4 Kg7 b3 Rh8 a4 Kg8 Rh4 Qe7 Rg4 Rh7 a5 Nf4 Bxf4 exf4 b4 Rc7 Qxf4 Rh3 Rg3 Rxg3 Qxg3 Qe5 Qxe5 dxe5 d6 Rd7
32   -0.61   01:54 755039K  Bxd5 exd5 Rb7 Qf3 Kh8 Bg5 Kg7 Re4 Rh8 Rb4 Rh7 h3 Nh5 Qxf7+ Kh8 Bxe7 Rxe7 Qf3 Rhf7 Qe3 Rxf1+ Bxf1 Nf4 Qf3 Kg7 g3 Nh5 Bd3 Nf6 Rh4 Qg8 Qe3 Kf8 Kh2 Nxd5 Qh6+ Qg7 Bxg6 Qxh6
33   -0.70   02:09 845487K  Bxd5 exd5 Rb7 Qf3 Kh8 Bg5 Kg7 Re4 Rh8 Rb4 Rh7 h3 Nh5 Qxf7+ Kh8 Bxe7 Rxe7 Qf3 Rhf7 Qg4 Rxf1+ Bxf1 Kg7 c4 Nf6 Qg3 bxc4 Rxc4 Rc7 Bd3 e4 Rxc7+ Qxc7 Bxa6 Nxd5 Qg5 Qf7 b4 e3
34   -0.72   03:09   1246M  Bxd5 exd5 Rb7 Qf3 Kh8 Qg3 Qd7 Rf3 Nh5 Qf2 Bd8 g4 Nf4 Bxf4 exf4 Qd4+ Kg8 Rxe8+ Qxe8 Qxf4 Qe5 Qxe5 dxe5 Kg2 Rd7 c4 bxc4 Bxc4 Bg5 Rf1 Kf8 b4 Bf4 h4 Ke7 Re1 Kd6 Bxa6 Ra7 b5 Kc5
35   -0.67   03:33   1414M  Bxd5 exd5 Rb7 Qf3 Kh8 Qg3 Qd7 Rf3 Nh5 Qf2 Bd8 g4 Nf4 Bxf4 exf4 Qd4+ Kg8 Rxe8+ Qxe8 Qxf4 Qe5 Qxe5 dxe5 Kg2 Rd7 c4 bxc4 Bxc4 Kf8 Re3 Bc7 g5 Ke7 Kf3 Rd8 Bxa6 Rxd5 b4 Rd2 h4 Rd4 Re4 Kd6 Rxd4+ exd4
36   -0.66   04:31   1796M  Bxd5 exd5 Rb7 Qf3 Kh8 Qg3 Qd7 Rf3 Nh5 Qf2 Bd8 g4 Nf4 Bxf4 exf4 Qd4+ Kg8 Rxe8+ Qxe8 Qxf4 Qe5 Qxe5 dxe5 Kg2 Rd7 c4 bxc4 Bxc4 Kg7 Re3 Bc7 g5 a5 Kf3 f5 gxf6+ Kxf6 Kg4 Bb6 Rf3+ Ke7 h4 Bd4 b4 axb4 axb4 e4 Rf4
37   -0.62   08:23   3372M  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 g5 Nh5 Bd2 Bd8 Re4 Kg7 Rh4 Rh8 b3 Rh7 a4 Qe7 axb5 axb5 Qh3 b4 Be2 Qc7 Ba6 Ra7 Bd3 Qb7 Be4 Kg8 Be3 Ra5 Qf3 Nf4 Rxh7 Kxh7 Bxf4 exf4 h4 Bb6 Qxf4
38   -0.69   15:17   6127M  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 g5 Nh7 Qg3 Qe7 Qh4 Rb8 Rf3 Rg8 Ref1 Rg7 Bd3 Bb6 Bd2 Kg8 Rh3 Qd7 Qh6 Qb7 Be4 Rc8 b3 Rxc2 Bxc2 Qxd5+ Rhf3 Qxd2 Rxf7 Rxf7 Qxg6+ Kh8 Qxf7 Qxc2 Qe8+ Kg7 Rf7+ Kg6 Qg8+ Kh5 Rxh7+ Kg4
39   -0.76   18:04   7270M  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Qh3+ Kg8 Bf5 Qc7 g5 Nh7 Be4 Bxg5 Bxg5 Nxg5 Qh6 Qe7 Re3 Rf8 Bd3 e4 h4 f5 hxg5 Qh7 Bxe4 Re8 Kg2 Qxh6 gxh6 fxe4 Rf6 Kh7 Kf2 Rc7 c3 Rd7 Rg3 Re5 Rgxg6 Rxd5 Ke3 a5 Kxe4 Rd2 Ke3 Rxb2 Rxd6
40   -0.80   29:21  11981M  Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Qh3+ Kg8 Bf5 Qc7 g5 Nh7 Rg1 b4 a4 Qa5 Be4 Qxa4 Ra1 Qb5 Rg4 Qd7 Qh4 Bf8 Rg3 Bg7 Rxa6 Rc8 Rf3 Nf8 Kg2 Rbb8 Bd3 Ra8 Rxa8 Rxa8 Qc4 Ra1 Rf1 Rxf1 Bxf1 Qf5 Bd3 e4 Qxe4 Qxe4+ Bxe4 Bxb2 h4
Nodes: 12246006864
Nodes/second: 6803329
Best move: Bxd5
Ponder move: exd5
Parent - By Peter Grayson (****) [gb] Date 2015-10-05 23:04
Yes, I think the scoring differences are probably marginal. See my reply to Raivis because until I can find out why I'm getting this strange position draw scenario the integrity of some of the analysis on my machines is in doubt. As I write this, Stockfish 051015 64 POPCNT has just selected 21.Nd5 at 40 ply!

21.a4 bxa4 22.Bc4 a3 23.b3 Rc7 24.Bb6 Kg7 25.Nd5 Bxd5 26.Bxd5 Qc8 27.Bxc7 Qxc7 28.Qf3 Rf8 29.Qd3 Qc5 30.Qxa6 Nh5 31.Rf3 Qxc2 32.Ref1 Nf4 33.R3f2 Qc7 34.Qxa3 Nxd5 35.exd5 f5 36.b4 Qc4 37.Rd1 Rc8 38.Qa4 Qc7 39.Rf3 e4 40.Rh3 Bf6 41.Rf1 Kg8 42.Rg3 Qh7 43.Rh3
  +/-  (0.75)   Depth: 40/68   00:22:07  25899MN
21.Nd5
  +/-  (0.82 ++)   Depth: 40/68   00:26:02  30452MN
21.Nd5 Bxd5
  +/-  (0.74 --)   Depth: 40/68   00:27:11  31898MN
21.Nd5 Bxd5 22.exd5 Rb7 23.Qf3 Kh8 24.g4 Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Qe7 28.Qh4 Kg8 29.Rg1 Bb6 30.Bd3 Bxe3 31.Rxe3 Qf8 32.Rf1 Qg7 33.Qg4 Rbe7 34.Be4 Rf8 35.Rg1 f5 36.gxf6 Nxf6 37.Qxg6 Qxg6 38.Bxg6 Rg7 39.Reg3 Kh8 40.Rf1 Kg8 41.Kg2 Nd7 42.Rf5 Rxf5 43.Bxf5 Nf6 44.Kf3 Kf8 45.Rxg7 Kxg7
  +/-  (0.84)   Depth: 40/68   00:32:55  39038MN
Parent - - By Lazy Frank (****) [lv] Date 2015-10-05 20:14
Not the optimistic scenario from Stockfish! (but nothing better too):

3qr1k1/1b1rbp2/p2p1np1/1p2p3/4P3/P1NBB2Q/1PP3PP/4RR1K w - - 0 21


depth 43
seldepth 64
score cp 77
nodes 54573430191

Nd5 Bxd5 exd5 Rb7 Qf3 Kh8 g4 Qd7 Be2 Bd8 g5 Nh7 Qg3 Rg8 Bd3 Rg7 Re2 Nf8 h4 Rh7 Rh2 Kg8 c3 Qe7 h5 Rxh5 Rxh5 gxh5 Qf3 Ng6 Qxh5 e4 Bb1 Bb6 Bxb6 Rxb6 Re1 Qe5 Rxe4 Qxd5 Kg1 Qc5+ Rd4 d5 Kf1 Qe7 Rxd5 Qc7 Ke1 Re6+ Kd1 Rd6 Rxd6 Qxd6+ Kc1
Parent - By Lazy Frank (****) [lv] Date 2015-10-06 02:47
And here Stockfish is more optimistic:

3qr2k/1r2bp2/p2p1np1/1p1Pp3/8/P2BBQ2/1PP3PP/4RR1K w - - 3 24


depth 43
seldepth 73
score cp 90
nodes 63392302023

g4 Qc8 Bd2 Bd8 g5 Nh5 a4 Qd7 a5 Kg8 b4 Nf4 Bxf4 exf4 Qxf4 Re5 Rxe5 dxe5 Qxe5 Be7 c3 Rc7 Be2 Bf8 Rf3 Rc8 Re3 Qd6 Qxd6 Bxd6 Kg2 Kf8 h4 Re8 Rxe8+ Kxe8 Kf3 Ke7 Ke4 Bg3 h5 gxh5 Bxh5 Be1 Kd3 Bg3 Kd4 Bd6 Be2
- - By Lazy Frank (****) [lv] Date 2015-10-06 05:39
Here coming next one very interesting position:

Nd5 - best move?

1. e4 c5 2. Nf3 e6 3. Nc3 a6 4. Be2 Nc6 5. d4 cxd4 6. Nxd4 Qc7 7. O-O Nf6
8. Be3 Be7 9. f4 d6 10. Kh1 O-O 11. Qe1 Nxd4 12. Bxd4 b5 13. Qg3 Bb7 14. a3
Rad8 15. Rae1 Rd7 16. Bd3 Qd8 17. Qh3 g6 18. f5 e5 19. Be3 Re8 20. fxg6
hxg6 21. Nd5 Bxd5 22. exd5 Rb7 23. Qf3 Kh8 24. g4 Qd7

4r2k/1r1qbp2/p2p1np1/1p1Pp3/6P1/P2BBQ2/1PP4P/4RR1K w - - 1 25


Unbelieveable, but after 24. ... Qd7 my Stockfish expecting rook sacrifice vs knight on square h5!
Parent - By Peter Grayson (****) [gb] Date 2015-10-06 22:30
Looks less adventurous on my machine changing from 24..Qd7 to ..Qc8 with the 27..Qc8 continuation being the same line as originally analysed with the 031015 engine that I included in the game analysis.

Analysis by Stockfish 051015 64 POPCNT:

24...Qd7 25.Be2 Bd8 26.g5 Nh7 27.Qg3 Rg8 28.Bd3 Qe7 29.h4 Qe8 30.Rg1 Nf8 31.Bd2 Kg7 32.Bb4 Qd7 33.Kg2 Rh8 34.Rh1 Kg8 35.Ref1 Rh5 36.Be2 Rh7 37.Qd3 Qc7 38.Bd2 Qe7 39.Qe3 Qe8 40.Bb4 Qd7 41.Qg3 Qe7 42.Bd2 Qe8 43.h5 gxh5 44.Bxh5 Rc7 45.c3 Ng6 46.Bg4
  +/-  (0.79)   Depth: 40/56   00:06:45  7933MN
24...Qd7
  +/-  (0.72 ++)   Depth: 41/56   00:08:15  9841MN
24...Qd7 25.Be2
  +/-  (0.79 --)   Depth: 41/56   00:09:09  10940MN
24...Qd7
  +/-  (0.72 ++)   Depth: 41/56   00:09:27  11311MN
24...Qd7 25.Qh3+
  +/-  (0.80 --)   Depth: 41/62   00:11:49  14352MN
24...Qc8 25.Bd2 Rf8 26.Rg1 Rg8 27.Qh3+ Nh7 28.Rgf1 Bd8 29.Re2 Rg7 30.Bh6 Qc5 31.Qg2 Qd4 32.b3 Rd7 33.Rd2 Qc5 34.g5 Rg8 35.Rdf2 Qa7 36.Qg4 Bb6 37.Rf3 Rc7 38.Qe4 Bc5 39.a4 bxa4 40.bxa4 Bd4 41.c4 Bc3 42.h4 Bd2 43.c5 Qxc5 44.Rxf7 Rxf7 45.Rxf7 Bf4 46.Qg2 a5 47.Rd7
  +/-  (0.94)   Depth: 41/68   00:29:23  35837MN
24...Qc8 25.Bd2
  +/-  (1.00 --)   Depth: 42/68   00:31:46  38845MN
24...Qc8
  +/-  (0.94 ++)   Depth: 42/68   00:33:52  41547MN
24...Qc8
  +/-  (0.85 ++)   Depth: 42/68   00:34:21  42196MN
24...Qc8 25.Bd2 Bd8 26.g5 Nh5 27.a4 Qd7 28.a5 Kg8 29.b4 Nf4 30.Bxf4 exf4 31.h4 Re5 32.Kg2 Qe8 33.Re4 Rxe4 34.Qxe4 Qxe4+ 35.Bxe4 f6 36.gxf6 Bxf6 37.Rxf4 Be5 38.Rg4 Rf7 39.Bxg6 Rf4 40.Rxf4 Bxf4 41.Bd3 Bd2 42.Bxb5 Bxb4 43.Bxa6 Bxa5 44.Kg3 Bc3 45.Bd3 Kf7 46.Kg4 Bf6
  +/-  (0.87)   Depth: 42/68   00:36:56  45410MN
24...Qc8
  +/-  (0.81 ++)   Depth: 43/68   00:37:46  46528MN
24...Qc8 25.Bd2 Bd8 26.g5 Nh5 27.a4 Qd7 28.a5 Kg8 29.b4 Nf4 30.Bxf4 exf4 31.h4 Re5 32.Kg2 Rc7 33.Qxf4 Qe7 34.Qf2 Rc3 35.Kh2 Rc8 36.Kh1 Rc7 37.Kg1 Qe8 38.Kh2 Rxe1 39.Rxe1 Re7 40.Rf1 Re3 41.Kg2 Qe7 42.Kg1 Re5 43.Qd4 Re1 44.Kg2 Qe5 45.Qxe5 Rxe5 46.c4 bxc4 47.Bxc4 Re4 48.Bxa6 Rg4+ 49.Kf3
  +/-  (0.81)   Depth: 43/68   00:38:29  47465MN
24...Qc8 25.Bd2 Bd8 26.g5 Nh5 27.a4 Qd7 28.a5 Kg8 29.b4 Nf4 30.Bxf4 exf4 31.h4 Re5 32.Kg2 Rc7 33.Qxf4 Qe7 34.Qf2 Rc3 35.Kh2 Rc7 36.Kh1 Qe8 37.Kg2 Qe7 38.Qg3 Qe8 39.Rxe5 Qxe5 40.Qxe5 dxe5 41.Kf3 Be7 42.Ke4 Kg7 43.Kxe5 Bxb4 44.Ke4 Ra7 45.Kd4 Bxa5 46.d6 Bb4 47.Kd5
  +/-  (0.81)   Depth: 44/68   00:40:05  49549MN
24...Qc8 25.Bd2 Bd8 26.g5 Nh5 27.a4 Qd7 28.a5 Kg8 29.b4 Nf4 30.Bxf4 exf4 31.h4 Re5 32.Kg2 Rc7 33.Qxf4 Qe7 34.Qf2 Rc3 35.Kh2 Rc7 36.Kh1 Rb7 37.Kg2 Rc7 38.Kh2 Qe8 39.Kg1 Qe7 40.Qg3 Qe8 41.Kg2 Qe7 42.Kh2 Rc3 43.Kg1 Ra3 44.Qf2 Bc7 45.Kg2 Ra4 46.c3 Ra2 47.Qxa2 Rxe1
  +/-  (0.81)   Depth: 45/68   00:43:46  54426MN
Up Topic The Rybka Lounge / Test Positions / Wei Yi-Bruzon Batista, 6th Hainan Danzou 2015

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