"Poor Fish": very hard test suite

[Jouni]

Yes SF needs nullmove off -button like Komodo .

[peter]

This one has such a button:

Code: Select all

8/4nk2/1p3p2/1r1p2pp/1P1R1N1P/6P1/3KPP2/8 w - - 0 1

Analysis by SF 171114IPx 64 POPCNTe:

50.Sxh5 Kg6 51.hxg5 fxg5 52.g4 Sc6 53.Td3 
  =  (0.00)   Tiefe: 7/7   00:00:00  10kN
...
50.hxg5 fxg5 51.Sxh5 Sc6 52.Td3 Se5 53.Td4 Sc6 
  =  (0.00)   Tiefe: 10/11   00:00:00  28kN
...
50.hxg5 fxg5 51.Sxh5 Sc6 52.Td3 Se5 53.Td4 Sc6 
  =  (0.00)   Tiefe: 23/11   00:00:04  5422kN
50.Sd3 
  =  (0.03 ++)   Tiefe: 24/25   00:00:08  13857kN
...
50.Sd3 
  +/=  (0.67 ++)   Tiefe: 24/32   00:00:13  43032kN
50.Sd3 Sf5 51.e3 Sxd4 52.exd4 Kg6 53.f3 Kf5 54.Kc3 g4 55.Kb3 gxf3 56.Sf2 Ke6 57.Ka4 Txb4+ 58.Kxb4 Kd6 59.Kc3 b5 60.Sd3 Kc6 61.Kd2 Kd6 
  +/-  (0.72)   Tiefe: 24/32   00:00:13  48566kN
...
50.Sd3 Sf5 51.e3 Sxd4 52.exd4 Kg6 53.f3 Kf5 54.Kc3 g4 55.Kb3 gxf3 56.Sf2 Kg6 57.Ka4 Txb4+ 58.Kxb4 f5 59.Sd3 f4 60.gxf4 Kf5 61.Kc3 Ke4 62.Kd2 b5 63.f5 Kxf5 64.Ke3 Kg4 65.Kf2 Kxh4 66.Kxf3 Kg5 67.Sf4 Kf6 
  +/=  (0.64)   Tiefe: 36/37   00:01:19  1320MN

BTW Zappa has such a button too, but it doesn't need it neither as for this position, Zappa default finds Nd3 also

[Vinvin]

So this test set will:

Code: Select all

1) Contain only positions from human games or human studies (with reference)

2) Be sound, so that between best move(s) and the others there is an important difference

3) Be really difficult to solve for engines

1) I plan to add references for the test set (around 150 are from human games).
2) It always has been my concern to have a CLEAR solution.
3) I plan to rerun the latest set next week.
The set with latest correction is here : http://home.scarlet.be/vincentlejeune/c ... 6beta6.epd

I found 45 references for this file : http://home.scarlet.be/vincentlejeune/c ... 6beta6.epd
thanks to the nice tool from Ed Schroder ( http://www.talkchess.com/forum/viewtopi ... 176#672176 ).
There are probably 100 more positions from real games that are not in DB from Rebel ProDeo.
Here are the numbers of the position followed by the games in PGN :

4)
[Event "Lugano"]
[Site "Lugano"]
[Date "1970.03.??"]
[Round "1"]
[White "Olafsson, F."]
[Black "Unzicker, W."]
[Result "1-0"]
[ECO "D41"]
[EventDate "1970.??.??"]
[PlyCount "93"]

1.c4 Nf6 2.Nf3 e6 3.Nc3 d5 4.d4 c5 5.cxd5 Nxd5 6.e4 Nxc3 7.bxc3 cxd4 8.
cxd4 Bb4+ 9.Bd2 Bxd2+ 10.Qxd2 O-O 11.Bc4 Nd7 12.O-O b6 13.Rad1 Bb7 14.Rfe1
Rc8 15.Bb3 Nf6 16.d5 exd5 17.exd5 Rc5 18.d6 Bd5 19.Qf4 Nh5 20.Qd4 Nf6 21.
Qf4 Nh5 22.Qd4 Nf6 23.Re5 Bxf3 24.gxf3 Rxe5 25.Qxe5 Re8 26.Qf4 Rf8 27.Ba4
Qb8 28.Qe5 Rd8 29.Qe7 h6 30.Qc7 Rc8 31.Qe7 Rd8 32.Bc6 Kh7 33.d7 Qc7 34.Rd6
Kg8 35.Kg2 a6 36.a4 Kh8 37.h3 Kg8 38.h4 Kh8 39.Kg1 Kg8 40.Kg2 Kh8 41.f4
Kg8 42.h5 Kh8 43.Qe5 Qb8 44.Rxf6 gxf6 45.Qxf6+ Kg8 46.Qxh6 Qc7 47.Qf6 1-0


5)
[Event "Dubai olm"]
[Site "Dubai olm"]
[Date "1986.11.??"]
[Round "1"]
[White "Georgiev, K."]
[Black "Ionescu, C."]
[Result "1-0"]
[WhiteElo "2445"]
[BlackElo "2495"]
[ECO "B50"]
[EventDate "1986.??.??"]
[PlyCount "105"]

1.e4 c5 2.Nf3 e6 3.b3 Nc6 4.Bb2 d6 5.d4 cxd4 6.Nxd4 a6 7.Be2 Bd7 8.c4 Nf6
9.Nc3 Be7 10.O-O O-O 11.Nc2 Rc8 12.f4 Qb6+ 13.Kh1 Rfd8 14.Bd3 Be8 15.Qe2
Qc7 16.Rae1 Bf8 17.Ne3 Ne7 18.Bb1 Qb8 19.e5 dxe5 20.fxe5 Nd7 21.Bxh7+ Kxh7
22.Ne4 Kg8 23.Ng5 g6 24.Ng4 Nf5 25.Rxf5 exf5 26.Qf2 Be7 27.Nf6+ Nxf6 28.
exf6 Bxf6 29.Qh4 Rd1 30.Qh7+ Kf8 31.Ba3+ Rd6 32.Bxd6+ Qxd6 33.Rxe8+ Kxe8
34.Qxf7+ Kd8 35.Ne6+ Qxe6 36.Qxe6 Rc6 37.Qg8+ Kc7 38.Qxg6 Rd6 39.g3 Rd1+
40.Kg2 Rd2+ 41.Kh3 Be7 42.a4 Rf2 43.Qf7 Kd7 44.Qd5+ Kc7 45.c5 Bd8 46.b4
Kc8 47.b5 axb5 48.axb5 Bc7 49.Qe6+ Kd8 50.c6 bxc6 51.bxc6 Rd2 52.Qg8+ Ke7
53.Qg5+ 1-0


6)
[Event "Groningen open"]
[Site "Groningen open"]
[Date "1994.12.??"]
[Round "1"]
[White "Vescovi, G."]
[Black "Gschwendtner, S."]
[Result "1-0"]
[WhiteElo "2455"]
[BlackElo "2270"]
[ECO "B53"]
[EventDate "1994.??.??"]
[PlyCount "61"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Qxd4 Nc6 5.Bb5 Bd7 6.Bxc6 Bxc6 7.Nc3 Nf6 8.
Bg5 e6 9.O-O-O Be7 10.Rhe1 O-O 11.Kb1 Qc7 12.Qd2 Rfd8 13.Nd4 Be8 14.f3
Rab8 15.g4 b5 16.Nce2 a5 17.Ng3 a4 18.Nh5 Nxh5 19.gxh5 Bxg5 20.Qxg5 Qc5
21.Qh4 a3 22.Rg1 Qb4 23.Nb3 d5 24.Rxg7+ Kxg7 25.h6+ Kf8 26.Qf6 Bc6 27.c3
Qc4 28.Rg1 Qd3+ 29.Ka1 axb2+ 30.Kxb2 Qe2+ 31.Ka1 1-0


10)
[Event "Asztalos mem"]
[Site "Miskolc"]
[Date "1963.??.??"]
[Round "6"]
[White "Brzozka, Stefan"]
[Black "Bronstein, David I"]
[Result "0-1"]
[ECO "A88"]
[EventDate "1963.??.??"]
[PlyCount "134"]

1.c4 f5 2.Nf3 Nf6 3.g3 g6 4.Bg2 Bg7 5.O-O O-O 6.d4 d6 7.Nc3 c6 8.Qc2 Kh8
9.b3 Na6 10.Bb2 Nc7 11.Rad1 Bd7 12.e3 Qe8 13.Rfe1 Rd8 14.Rd2 Nh5 15.d5 Qf7
16.dxc6 bxc6 17.Ne2 c5 18.Nf4 Nf6 19.Ng5 Qg8 20.Bc3 Rde8 21.Ba5 Ne6 22.
Ngxe6 Bxe6 23.Nxe6 Qxe6 24.Qd3 Ne4 25.Qd5 Qxd5 26.Rxd5 Bc3 27.Bxc3+ Nxc3
28.Rd2 Ne4 29.Rb2 a5 30.f3 Nf6 31.Kf2 Rb8 32.Ke2 Rb6 33.Kd3 e5 34.f4 e4+
35.Kc3 Kg7 36.Bf1 h5 37.h4 Rfb8 38.Be2 a4 39.Reb1 a3 40.Rd2 Kf7 41.Rbd1
Ke7 42.Rd5 Ne8 43.R1d2 Nc7 44.Bd1 Na6 45.Bc2 Nb4 46.Bb1 Ra6 47.Rd1 Nxd5+
48.Rxd5 Rxb3+ 49.Kxb3 Rb6+ 50.Kc2 Rb2+ 51.Kc1 Re2 52.Rd1 Rxe3 53.Rg1 Rc3+
54.Kd2 Rxc4 55.Bc2 d5 56.Rb1 d4 57.Bd1 Rc3 58.Rb3 e3+ 59.Ke2 Rc1 60.Rxa3
c4 61.Ra7+ Kd6 62.Ba4 Rh1 63.Rd7+ Kc5 64.Rc7+ Kb4 65.a3+ Kc3 66.Bb5 Rh2+
67.Kf1 d3 0-1


14)
[Event "USSR"]
[Site "USSR"]
[Date "1976.??.??"]
[Round "1"]
[White "Bagirov, V."]
[Black "Grigorian, K."]
[Result "1-0"]
[ECO "A01"]
[EventDate "1976.??.??"]
[PlyCount "59"]

1.b3 Nf6 2.Bb2 g6 3.e4 d6 4.g3 Bg7 5.Bg2 O-O 6.Ne2 e5 7.O-O Nh5 8.d4 Nd7
9.Nd2 Qe7 10.f4 exd4 11.Bxd4 f5 12.Bxg7 Nxg7 13.Nc3 Nf6 14.Re1 Qd8 15.Nc4
fxe4 16.Nxe4 Nxe4 17.Bxe4 Rb8 18.Qd4 b6 19.Bd5+ Kh8 20.Re3 c5 21.Qc3 b5
22.Rae1 Qf6 23.Qxf6 Rxf6 24.Re8+ Nxe8 25.Rxe8+ Kg7 26.Rg8+ Kh6 27.Ne3 a5
28.h4 a4 29.Kf2 c4 30.b4 1-0


21)
[Event "FIDE GP"]
[Site "Astrakhan RUS"]
[Date "2010.05.10"]
[Round "1"]
[White "Gashimov, V."]
[Black "Ivanchuk, V."]
[Result "1-0"]
[WhiteElo "2734"]
[BlackElo "2741"]
[ECO "C88"]
[EventDate "2010.??.??"]
[PlyCount "71"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 O-O 8.h3 Bb7
9.d3 d6 10.a3 Nb8 11.Nbd2 Nbd7 12.Nf1 Re8 13.Ba2 Bf8 14.Ng5 Re7 15.f4 h6
16.Nf3 d5 17.fxe5 Nxe5 18.Nxe5 Rxe5 19.Bf4 Re8 20.e5 Nh7 21.d4 Ng5 22.Ng3
Ne6 23.Be3 g6 24.Rf1 Bg7 25.c3 c5 26.Qg4 Rc8 27.Rf2 Rc7 28.Raf1 Bc8 29.Qd1
c4 30.Bb1 Qh4 31.Kh2 a5 32.Ne2 Rf8 33.Qd2 Kh7 34.Rf6 Re7 35.R6f4 Nxf4 36.
Rxf4 1-0


26)
[Event "FIDE (29) 1973-1975"]
[Site "San Juan cm qf"]
[Date "1974.??.??"]
[Round "1"]
[White "Spassky, B."]
[Black "Byrne, R."]
[Result "1-0"]
[WhiteElo "2650"]
[BlackElo "2595"]
[ECO "B52"]
[EventDate "1974.??.??"]
[PlyCount "117"]

1.e4 c5 2.Nf3 d6 3.Bb5+ Bd7 4.Bxd7+ Qxd7 5.c4 e5 6.Nc3 Nc6 7.d3 g6 8.a3
Bg7 9.Rb1 Nge7 10.b4 b6 11.O-O O-O 12.Nd5 Nxd5 13.cxd5 Nd4 14.Nxd4 cxd4
15.Bd2 Rac8 16.Qb3 Rc7 17.Rbc1 Rfc8 18.b5 Rxc1 19.Rxc1 Rxc1+ 20.Bxc1 Qc7
21.Qc4 Qxc4 22.dxc4 f6 23.Kf1 Bf8 24.a4 Be7 25.Ke2 Kf7 26.Bd2 f5 27.exf5
gxf5 28.Kd3 Bf6 29.f3 h5 30.a5 Ke8 31.a6 Kd7 32.g3 Kc7 33.h3 Kd7 34.Ba5
Kc8 35.Be1 Kd7 36.Bf2 Ke8 37.Be1 Kf7 38.Bb4 Be7 39.f4 exf4 40.gxf4 Ke8 41.
Kxd4 Kd7 42.Kd3 Kc7 43.Ke3 Bf6 44.Kf3 h4 45.Ke3 Bg7 46.Kd3 Bf6 47.Bd2 Kd7
48.Be3 Kc7 49.Bf2 Kc8 50.c5 dxc5 51.d6 Kd7 52.Bxc5 Bd8 53.Bb4 Ke6 54.Kc4
Bf6 55.Bc5 Bd8 56.Bd4 Kxd6 57.Be5+ Ke6 58.Bb8 Kd7 59.Kd5 1-0


27)
[Event "FIDE World Cup 2011"]
[Site "Khanty-Mansiysk RUS"]
[Date "2011.08.31"]
[Round "2.1"]
[White "Gashimov, V."]
[Black "Azarov, S."]
[Result "1-0"]
[WhiteElo "2760"]
[BlackElo "2648"]
[ECO "C63"]
[EventDate "2011.??.??"]
[PlyCount "45"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 f5 4.d3 fxe4 5.dxe4 Nf6 6.Be3 Bb4+ 7.c3 Be7 8.Bxc6
bxc6 9.Nxe5 Ba6 10.Nd2 Rb8 11.Qa4 Qc8 12.O-O-O O-O 13.Bg5 Kh8 14.c4 c5 15.
h4 Rb6 16.h5 d6 17.Ng6+ hxg6 18.hxg6+ Kg8 19.Qa3 Qg4 20.f4 Rfb8 21.Rh4 Qe6
22.Rdh1 Kf8 23.f5 1-0



31)
[Event "Tilburg"]
[Site "Tilburg"]
[Date "1991.??.??"]
[Round "4"]
[White "Short, Nigel D"]
[Black "Timman, Jan H"]
[Result "1-0"]
[WhiteElo "2660"]
[BlackElo "2630"]
[ECO "B04"]
[EventDate "1991.??.??"]
[PlyCount "67"]

1.e4 Nf6 2.e5 Nd5 3.d4 d6 4.Nf3 g6 5.Bc4 Nb6 6.Bb3 Bg7 7.Qe2 Nc6 8.O-O O-O
9.h3 a5 10.a4 dxe5 11.dxe5 Nd4 12.Nxd4 Qxd4 13.Re1 e6 14.Nd2 Nd5 15.Nf3
Qc5 16.Qe4 Qb4 17.Bc4 Nb6 18.b3 Nxc4 19.bxc4 Re8 20.Rd1 Qc5 21.Qh4 b6 22.
Be3 Qc6 23.Bh6 Bh8 24.Rd8 Bb7 25.Rad1 Bg7 26.R8d7 Rf8 27.Bxg7 Kxg7 28.R1d4
Rae8 29.Qf6+ Kg8 30.h4 h5 31.Kh2 Rc8 32.Kg3 Rce8 33.Kf4 Bc8 34.Kg5 1-0

32)
[Event "Switzerland"]
[Site "Switzerland"]
[Date "1980.??.??"]
[Round "1"]
[White "Gusia"]
[Black "Barlov, D."]
[Result "1-0"]
[ECO "B49"]
[EventDate "1980.??.??"]
[PlyCount "43"]

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nc6 5.Nc3 Qc7 6.Be2 a6 7.O-O Nf6 8.Be3
Bb4 9.Na4 Bd6 10.Nxc6 bxc6 11.Nb6 Rb8 12.Nxc8 Rxc8 13.f4 e5 14.Kh1 O-O 15.
f5 Nxe4 16.f6 g6 17.Qe1 Bc5 18.Bxc5 Nxc5 19.Qh4 e4 20.Qh6 Ne6 21.Bg4 d5
22.Rf5 1-0

33)
[Event "Switzerland"]
[Site "Switzerland"]
[Date "1980.??.??"]
[Round "1"]
[White "Gusia"]
[Black "Barlov, D."]
[Result "1-0"]
[ECO "B49"]
[EventDate "1980.??.??"]
[PlyCount "43"]

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nc6 5.Nc3 Qc7 6.Be2 a6 7.O-O Nf6 8.Be3
Bb4 9.Na4 Bd6 10.Nxc6 bxc6 11.Nb6 Rb8 12.Nxc8 Rxc8 13.f4 e5 14.Kh1 O-O 15.
f5 Nxe4 16.f6 g6 17.Qe1 Bc5 18.Bxc5 Nxc5 19.Qh4 e4 20.Qh6 Ne6 21.Bg4 d5
22.Rf5 1-0


35)
[Event "Corus B"]
[Site "Wijk aan Zee NED"]
[Date "2006.01.14"]
[Round "1"]
[White "Carlsen, M."]
[Black "L'Ami, E."]
[Result "1-0"]
[WhiteElo "2625"]
[BlackElo "2550"]
[ECO "C91"]
[EventDate "2006.??.??"]
[PlyCount "73"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 d6 8.c3 O-O
9.d4 Bg4 10.Be3 exd4 11.cxd4 Na5 12.Bc2 c5 13.h3 Bxf3 14.Qxf3 cxd4 15.Bxd4
Rc8 16.Qd1 Nc6 17.Nc3 b4 18.Ne2 Nxd4 19.Nxd4 g6 20.Qd2 Qb6 21.Rad1 Nd7 22.
Bb3 Nc5 23.Bd5 Bf6 24.Nf3 Kg7 25.Nh2 h5 26.g4 Rh8 27.Kg2 hxg4 28.Nxg4 Nd7
29.Bxf7 Kxf7 30.Qf4 Ke6 31.Nxf6 Nxf6 32.e5 Qb7+ 33.Kg1 dxe5 34.Rxe5+ Kf7
35.Rd6 Rxh3 36.Qxf6+ Kg8 37.Rd8+ 1-0


43)
[Event "TCh-AUT 2010-11"]
[Site "St Veit/Glan AUT"]
[Date "2011.03.03"]
[Round "8"]
[White "Volokitin, And"]
[Black "Antoniewski, R."]
[Result "1-0"]
[WhiteElo "2676"]
[BlackElo "2604"]
[ECO "B48"]
[EventDate "2011.??.??"]
[PlyCount "113"]

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nc6 5.Nc3 Qc7 6.Be3 a6 7.Qd2 Nf6 8.O-O-O
Bb4 9.f3 Ne5 10.Nb3 b5 11.Qe1 Rb8 12.Qg3 O-O 13.Bd4 Bd6 14.f4 Nh5 15.fxe5
Nxg3 16.exd6 Qxd6 17.hxg3 Qxg3 18.Bc5 Re8 19.Bd6 Qg5+ 20.Kb1 Rb6 21.e5
Rxd6 22.exd6 Bb7 23.a4 bxa4 24.Nxa4 Bxg2 25.Rg1 Qh4 26.Rxg2 Qxa4 27.Nc5
Qf4 28.Nxd7 Rd8 29.c4 Rxd7 30.c5 g6 31.Rc2 Qf3 32.Rdc1 Qd5 33.c6 Qxd6 34.
cxd7 Qxd7 35.Bxa6 h5 36.b4 Qd6 37.b5 Qd3 38.Ka2 Qe3 39.Rc6 Qd3 40.R1c4 Qd5
41.Ka3 Kg7 42.b6 Qd3+ 43.Ka4 Qd1+ 44.Ka5 Qd2+ 45.Kb5 Qb2+ 46.Rb4 Qe5+ 47.
Rc5 Qe2+ 48.Rbc4 h4 49.b7 Qb2+ 50.Rb4 Qh2 51.Ka5 Qd6 52.Rc8 Qd5+ 53.Rb5
Qd2+ 54.Kb6 Qd6+ 55.Ka7 Qd7 56.Rbc5 h3 57.R8c7 1-0


47)
[Event "Tilburg "]
[Site "Tilburg "]
[Date "1998.10.29"]
[Round "1"]
[White "Svidler, P."]
[Black "Van Wely, L."]
[Result "1-0"]
[WhiteElo "2710"]
[BlackElo "2635"]
[ECO "B31"]
[EventDate "1998.??.??"]
[PlyCount "119"]

1.e4 c5 2.Nf3 Nc6 3.Nc3 g6 4.Bb5 Bg7 5.O-O d6 6.e5 dxe5 7.Bxc6+ bxc6 8.Re1
Qc7 9.d3 Nf6 10.Nxe5 Nd5 11.Qe2 Nxc3 12.bxc3 Qxe5 13.Qxe5 Bxe5 14.Rxe5 c4
15.dxc4 f6 16.Rc5 Bd7 17.Ra5 Kf7 18.Be3 Bf5 19.Rb1 Bxc2 20.Rb7 Rhb8 21.
Rxb8 Rxb8 22.h4 Rb7 23.Bxa7 Bd3 24.Bc5 Bxc4 25.a4 Ke6 26.Ra8 Kd5 27.Be3
Rb1+ 28.Kh2 Ra1 29.a5 c5 30.Ra7 Kd6 31.Bh6 Bd5 32.Bf4+ e5 33.Bh6 Ra2 34.
Ra6+ Ke7 35.Be3 c4 36.Bc5+ Kf7 37.Rd6 Be4 38.a6 f5 39.a7 f4 40.Rd7+ Ke6
41.Rxh7 Bc6 42.Rh6 Be4 43.Rh8 Kd7 44.Bb6 Ra6 45.Rd8+ Ke7 46.f3 Bc6 47.Rg8
Kf7 48.Rc8 Bd5 49.Rd8 Ke6 50.Bc5 Bb7 51.Kh3 Ra5 52.Re8+ Kf5 53.Bd6 Bc6 54.
Rxe5+ Rxe5 55.Bxe5 Kxe5 56.Kg4 Kf6 57.Kxf4 Bb7 58.g4 Bc6 59.Ke3 Ke5 60.f4+
1-0


52)
[Event "Moscow"]
[Site "Moscow"]
[Date "1951.??.??"]
[Round "1"]
[White "Gusev, Nikolai"]
[Black "Averbach, Y."]
[Result "1-0"]
[ECO "B70"]
[EventDate "1951.??.??"]
[PlyCount "73"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.Be2 Bg7 7.Nb3 Nc6 8.O-O
Be6 9.f4 Rc8 10.f5 Bd7 11.g4 Ne5 12.g5 Ng8 13.Nd5 f6 14.Be3 b6 15.Nd4 Kf7
16.c3 Qe8 17.Ne6 Bxe6 18.fxe6+ Kf8 19.Nxf6 Nxf6 20.gxf6 Bxf6 21.Bh6+ Kg8
22.Rxf6 exf6 23.Qxd6 Rc6 24.Qxe5 fxe5 25.Rf1 Rc8 26.Bd1 Rc4 27.Bb3 b5 28.
Bxc4 bxc4 29.b3 a5 30.bxc4 Qe7 31.Kg2 Qa3 32.Rf2 Qe7 33.Rf1 g5 34.Rf5 g4
35.c5 Qd8 36.c6 Qe7 37.c7 1-0


54)
[Event "Fiorenzuola d'Arda m"]
[Site "Fiorenzuola d'Arda m"]
[Date "1997.06.06"]
[Round "1"]
[White "Efimov, I."]
[Black "Comp M-Chess Pro"]
[Result "1-0"]
[WhiteElo "2530"]
[ECO "C00"]
[EventDate "1997.??.??"]
[PlyCount "52"]

1.Nf3 c5 2.g3 d5 3.Bg2 Nc6 4.O-O e6 5.d3 Nf6 6.Nbd2 Be7 7.e4 O-O 8.e5 Nd7
9.Re1 b5 10.h4 Qc7 11.Qe2 Ba6 12.Nf1 Rae8 13.Bf4 Nb6 14.N1h2 Na4 15.Ng5 h6
16.Qh5 hxg5 17.hxg5 g6 18.Qh6 Nd4 19.Ng4 Nf5 20.Qh3 c4 21.Nf6+ Bxf6 22.
gxf6 cxd3 23.g4 Nc5 24.gxf5 exf5 25.Qh6 Ne6 26.Re3 dxc2 1-0


56)
[Event "Lasker mem"]
[Site "Berlin-Ost"]
[Date "1968.??.??"]
[Round "?"]
[White "Uhlmann, Wolfgang"]
[Black "Malich, Burkhard"]
[Result "1/2-1/2"]
[ECO "A12"]
[EventDate "1968.??.??"]
[PlyCount "122"]

1.c4 Nf6 2.Nf3 c6 3.b3 d5 4.Bb2 Bf5 5.d3 e6 6.Nbd2 Be7 7.Nh4 Bg6 8.Nxg6
hxg6 9.g3 a5 10.Bg2 Nbd7 11.O-O O-O 12.cxd5 cxd5 13.e4 a4 14.bxa4 Nc5 15.
Nb3 Nxa4 16.Bd4 b5 17.Rc1 b4 18.Qe2 Re8 19.Rc2 Rc8 20.Rxc8 Qxc8 21.exd5
exd5 22.Rc1 Qd7 23.Qc2 Bf8 24.h3 Kh7 25.Na5 Qb5 26.Nb3 Re6 27.Kh2 Qe8 28.
Bf3 Bd6 29.Qd2 Qb5 30.Kg2 Re8 31.Rc2 Kg8 32.Ba1 Nd7 33.Nd4 Qa5 34.a3 Nab6
35.Rc1 Ne5 36.Nc6 Nxc6 37.Rxc6 Bf8 38.Bd4 Nd7 39.axb4 Qb5 40.Rc1 Ne5 41.
Bxe5 Rxe5 42.Rc8 Qd7 43.Qc3 d4 44.Qc4 g5 45.Rb8 Qd6 46.Qc8 g6 47.b5 Rc5
48.Bc6 Rc2 49.Qe8 Kg7 50.Rd8 Qe7 51.Qxe7 Bxe7 52.Rd7 Kf8 53.Rxd4 Rxf2+ 54.
Kxf2 Bc5 55.Kf3 Bxd4 56.Ke4 Bf2 57.g4 Bb6 58.Bd5 Ke7 59.Bb3 f6 60.Kd5 Kd7
61.Bc2 Ba7 1/2-1/2

62)
[Event "Hastings7576"]
[Site "Hastings"]
[Date "1975.12.29"]
[Round "1"]
[White "Kaplan, Julio P"]
[Black "Bronstein, David I"]
[Result "0-1"]
[WhiteElo "2445"]
[BlackElo "2590"]
[ECO "C11"]
[EventDate "1975.??.??"]
[PlyCount "52"]

1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 dxe4 5.Nxe4 Be7 6.Bxf6 gxf6 7.Nf3 Nd7 8.
Qd2 c5 9.d5 f5 10.dxe6 fxe4 11.exd7+ Qxd7 12.Qc3 O-O 13.Nd2 Qf5 14.O-O-O
Qxf2 15.Nxe4 Qf4+ 16.Nd2 Bg4 17.Re1 Bg5 18.Bd3 Rae8 19.Ref1 Qe3 20.h3 Be2
21.Rf5 Bh6 22.Bxe2 Qxc3 23.bxc3 Rxe2 24.Rd5 Rxd2 25.Rxd2 Rd8 26.Rd1 c4 0-1


67)
[Event "Spain"]
[Site "Spain"]
[Date "1994.??.??"]
[Round "1"]
[White "Spraggett, K."]
[Black "Morovic Fernandez, I."]
[Result "1-0"]
[ECO "A29"]
[EventDate "1994.??.??"]
[PlyCount "83"]

1.c4 Nf6 2.Nc3 e5 3.Nf3 Nc6 4.g3 Bb4 5.Bg2 O-O 6.O-O e4 7.Ne1 Bxc3 8.dxc3
h6 9.Nc2 Re8 10.Ne3 d6 11.Qc2 Re5 12.f4 exf3 13.exf3 Re8 14.Bd2 Be6 15.f4
Ng4 16.Nd5 Ne7 17.h3 Bxd5 18.cxd5 Nf6 19.c4 Qd7 20.Rae1 Nf5 21.Qd3 h5 22.
Rxe8+ Rxe8 23.Re1 h4 24.Rxe8+ Nxe8 25.g4 Ng3 26.f5 Nf6 27.Bg5 Qe8 28.Qe3
Qxe3+ 29.Bxe3 a5 30.Kf2 g5 31.Ke1 Nfe4 32.Bxe4 Nxe4 33.Ke2 f6 34.Kd3 Nc5+
35.Bxc5 dxc5 36.Kc3 Kf7 37.Kb3 Ke7 38.Ka4 b6 39.Kb5 Kd6 40.b3 Kd7 41.Ka6
Kd6 42.Kb7 1-0


69)
[Event "Chigorin Memorial Open"]
[Site "St Petersburg RUS"]
[Date "2011.10.21"]
[Round "8.50"]
[White "Tunik, G."]
[Black "Duzhakov, I."]
[Result "1-0"]
[WhiteElo "2412"]
[BlackElo "2325"]
[ECO "E92"]
[EventDate "2011.10.14"]
[PlyCount "117"]

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5 7.Be3 exd4 8.Nxd4
Re8 9.f3 c6 10.Bf2 d5 11.exd5 cxd5 12.O-O Nc6 13.c5 Nh5 14.Qd2 Be5 15.g3
Ng7 16.Rfe1 Be6 17.Nxe6 Nxe6 18.Qxd5 Qxd5 19.Nxd5 Rad8 20.Nc3 Rd2 21.Rab1
Ng5 22.Kf1 Bd4 23.Bxd4 Nxd4 24.f4 Ngf3 25.Bxf3 Rxe1+ 26.Rxe1 Nxf3 27.Re2
Nxh2+ 28.Kg2 Rxe2+ 29.Nxe2 Ng4 30.Nc3 Ne3+ 31.Kf3 Nf5 32.g4 Nd4+ 33.Ke4
Ne6 34.b4 h5 35.gxh5 gxh5 36.f5 Nc7 37.Nd5 Nxd5 38.Kxd5 h4 39.Ke4 h3 40.
Kf3 Kg7 41.b5 Kf6 42.a4 Kxf5 43.a5 Ke6 44.c6 b6 45.axb6 axb6 46.Kg3 Kd6
47.Kxh3 Kc7 48.Kg4 Kc8 49.Kf5 Kc7 50.Kf6 Kc8 51.Kxf7 Kd8 52.Ke6 Kc8 53.c7
Kxc7 54.Ke7 Kc8 55.Kd6 Kb7 56.Kd7 Ka7 57.Kc7 Ka8 58.Kxb6 Kb8 59.Ka6 1-0


78)
[Event "Smirin vs Computers"]
[Site "KC-CB INT"]
[Date "2002.04.24"]
[Round "6"]
[White "Smirin, I."]
[Black "HIARCS 8"]
[Result "1/2-1/2"]
[WhiteElo "2685"]
[ECO "A30"]
[EventDate "2002.??.??"]
[PlyCount "119"]

1.c4 c5 2.Nf3 Nf6 3.g3 d5 4.cxd5 Nxd5 5.Bg2 Nc6 6.d4 cxd4 7.Nxd4 Ndb4 8.
Nxc6 Qxd1+ 9.Kxd1 Nxc6 10.Nc3 Bd7 11.Be3 e5 12.Rc1 Rd8 13.Ke1 Be7 14.f4
exf4 15.gxf4 O-O 16.Nd5 Bd6 17.Kf2 Be6 18.Rhd1 Rd7 19.Nc3 Rfd8 20.a3 Ne7
21.Be4 Nf5 22.Bxf5 Bxf5 23.Rd4 a6 24.Na4 Be7 25.Rxd7 Bxd7 26.Nc3 Bh4+ 27.
Kg1 f5 28.Rd1 Bc6 29.Rxd8+ Bxd8 30.Bd4 Kf7 31.e3 h6 32.Ne2 g5 33.Kf2 Bc7
34.Bc3 Be4 35.Kg3 g4 36.Bd4 Kg6 37.Kf2 h5 38.Bc3 Bd8 39.Bd4 a5 40.Bc3 a4
41.Nd4 Bh4+ 42.Kg1 Be7 43.Kf2 Bd5 44.Kg3 h4+ 45.Kf2 Be4 46.Kg1 g3 47.h3
Bc5 48.Bb4 Bxb4 49.axb4 Kf7 50.Nb5 Ke6 51.Nc3 Bc2 52.Kg2 Kd6 53.Kg1 Kc6
54.Kg2 b5 55.Kg1 Bd3 56.Kg2 Be4+ 57.Kg1 Bc2 58.Kg2 Bd3 59.Kg1 Be4 60.Kf1
1/2-1/2


84)
[Event "ch-Euro Youth b18"]
[Site "Albena BUL"]
[Date "2011.09.18"]
[Round "7.1"]
[White "Grandelius, N."]
[Black "Raznikov, D."]
[Result "1-0"]
[WhiteElo "2536"]
[BlackElo "2433"]
[ECO "A30"]
[EventDate "2011.09.11"]
[PlyCount "131"]

1.c4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 g6 5.g3 Bg7 6.Nc2 d6 7.Bg2 Be6 8.Ne3
Qd7 9.Nd5 Rc8 10.O-O Bh3 11.Nbc3 Bxg2 12.Kxg2 Ne5 13.b3 Nf6 14.Nxf6+ Bxf6
15.Nd5 Bg7 16.Bg5 Nc6 17.Rc1 h6 18.Be3 O-O 19.Qd2 Kh7 20.Rfd1 Rfd8 21.Qd3
e6 22.Nf4 Qe7 23.Qe4 Kg8 24.Bd2 a6 25.Bc3 d5 26.cxd5 exd5 27.Qxe7 Nxe7 28.
Ba5 Rxc1 29.Rxc1 Rd7 30.Bb6 Nc6 31.Nd3 Re7 32.Kf1 h5 33.Rc5 Rd7 34.Nf4 Ne7
35.Rc2 Be5 36.Nd3 Bd6 37.Ke1 f6 38.Bc5 Bxc5 39.Rxc5 b6 40.Rc2 a5 41.Nf4
Kf7 42.h4 Ra7 43.Rd2 Rc7 44.Kd1 Rc5 45.Rd4 Ke8 46.Kd2 Kf7 47.a3 g5 48.b4
axb4 49.axb4 Rb5 50.Nd3 Nf5 51.e3 Nxd4 52.exd4 Kg6 53.Kc3 Kf5 54.f3 g4 55.
Kb3 gxf3 56.Nf2 Kg6 57.Ka4 Rxb4+ 58.Kxb4 f5 59.Kb5 f4 60.gxf4 Kf5 61.Kxb6
Kxf4 62.Kc5 Kg3 63.Nd3 Kxh4 64.Kxd5 Kg3 65.Ke4 h4 66.Ke3 1-0


89)
[Event "Moskou ch-URS"]
[Site "Moskou ch-URS"]
[Date "1955.02.??"]
[Round "1"]
[White "Kotov, A."]
[Black "Botvinnik, M."]
[Result "0-1"]
[ECO "D46"]
[EventDate "1955.??.??"]
[PlyCount "130"]

1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 e6 5.e3 Nbd7 6.Bd3 Bb4 7.O-O O-O 8.Bd2 Bd6
9.b3 Qe7 10.Qc2 e5 11.cxd5 cxd5 12.dxe5 Nxe5 13.Nd4 Nxd3 14.Qxd3 Qe5 15.f4
Qe7 16.Rac1 Rd8 17.Rc2 Bc5 18.Na4 Bxd4 19.Qxd4 Bf5 20.Bb4 Qd7 21.Rc3 Ne4
22.Rcc1 b6 23.Rfd1 f6 24.Nc3 Nxc3 25.Rxc3 Be4 26.Qd2 Qg4 27.h3 Qg6 28.Qf2
h5 29.Kh2 a5 30.Ba3 b5 31.Bc5 b4 32.Rcc1 Rdc8 33.Bd4 Bc2 34.Rd2 Be4 35.
Rdd1 Qf5 36.Qe2 Qg6 37.Qf2 a4 38.Rxc8+ Rxc8 39.bxa4 Qe8 40.Rd2 Qxa4 41.Qh4
Rc2 42.Rxc2 Qxc2 43.Qg3 Qxa2 44.Bxf6 Qxg2+ 45.Qxg2 Bxg2 46.Bd4 Be4 47.Kg3
Kf7 48.h4 g6 49.Kf2 Ke6 50.Ke2 Kf5 51.Kd2 Kg4 52.Bf6 Kg3 53.Be7 Kh3 54.Bf6
Kg4 55.Be7 Bf5 56.Bf6 Kf3 57.Be7 b3 58.Kc3 Be6 59.Bc5 g5 60.fxg5 d4+ 61.
exd4 Kg3 62.Ba3 Kxh4 63.Kd3 Kxg5 64.Ke4 h4 65.Kf3 Bd5+ 0-1


90)
[Event "Linares"]
[Site "Linares"]
[Date "1998.03.04"]
[Round "1"]
[White "Topalov, V."]
[Black "Shirov, A."]
[Result "0-1"]
[WhiteElo "2740"]
[BlackElo "2710"]
[ECO "D85"]
[EventDate "1998.??.??"]
[PlyCount "106"]

1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7 7.Bb5+ c6 8.Ba4
O-O 9.Ne2 Nd7 10.O-O e5 11.f3 Qe7 12.Be3 Rd8 13.Qc2 Nb6 14.Bb3 Be6 15.Rad1
Nc4 16.Bc1 b5 17.f4 exd4 18.Nxd4 Bg4 19.Rde1 Qc5 20.Kh1 a5 21.h3 Bd7 22.a4
bxa4 23.Ba2 Be8 24.e5 Nb6 25.f5 Nd5 26.Bd2 Nb4 27.Qxa4 Nxa2 28.Qxa2 Bxe5
29.fxg6 hxg6 30.Bg5 Rd5 31.Re3 Qd6 32.Qe2 Bd7 33.c4 Bxd4 34.cxd5 Bxe3 35.
Qxe3 Re8 36.Qc3 Qxd5 37.Bh6 Re5 38.Rf3 Qc5 39.Qa1 Bf5 40.Re3 f6 41.Rxe5
Qxe5 42.Qa2+ Qd5 43.Qxd5+ cxd5 44.Bd2 a4 45.Bc3 Kf7 46.h4 Ke6 47.Kg1 Bh3
48.gxh3 Kf5 49.Kf2 Ke4 50.Bxf6 d4 51.Be7 Kd3 52.Bc5 Kc4 53.Be7 Kb3 0-1


102)
[Event "Corus A"]
[Site "Wijk aan Zee NED"]
[Date "2006.01.14"]
[Round "1"]
[White "Karjakin, Sergey"]
[Black "Anand, V."]
[Result "0-1"]
[WhiteElo "2660"]
[BlackElo "2792"]
[ECO "B90"]
[EventDate "2006.??.??"]
[PlyCount "74"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Be3 e5 7.Nb3 Be6 8.f3 Be7
9.Qd2 O-O 10.O-O-O Nbd7 11.g4 b5 12.g5 b4 13.Ne2 Ne8 14.f4 a5 15.f5 a4 16.
Nbd4 exd4 17.Nxd4 b3 18.Kb1 bxc2+ 19.Nxc2 Bb3 20.axb3 axb3 21.Na3 Ne5 22.
h4 Ra5 23.Qc3 Qa8 24.Bg2 Nc7 25.Qxc7 Rc8 26.Qxe7 Nc4 27.g6 hxg6 28.fxg6
Nxa3+ 29.bxa3 Rxa3 30.gxf7+ Kh7 31.f8=N+ Rxf8 32.Qxf8 Ra1+ 33.Kb2 Ra2+ 34.
Kc3 Qa5+ 35.Kd3 Qb5+ 36.Kd4 Ra4+ 37.Kc3 Qc4+ 0-1


105)
[Event "Canadian Open"]
[Site "Ottawa CAN"]
[Date "2007.07.14"]
[Round "9"]
[White "Sandipan, C."]
[Black "Tiviakov, S."]
[Result "1-0"]
[WhiteElo "2563"]
[BlackElo "2648"]
[ECO "E17"]
[EventDate "2007.??.??"]
[PlyCount "59"]

1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3 Bb7 5.Bg2 Be7 6.O-O O-O 7.d5 exd5 8.Nh4 c6
9.cxd5 Nxd5 10.Nf5 Nc7 11.e4 d5 12.Nc3 Bf6 13.exd5 cxd5 14.Bf4 Nba6 15.Re1
Qd7 16.Bh3 Ne6 17.Ne4 Bxb2 18.Rb1 Bc8 19.Ng5 Bf6 20.Qh5 Bxg5 21.Bxg5 Re8
22.Bf6 gxf6 23.Qh6 Nac5 24.Rbd1 Qb7 25.Rd4 Ne4 26.Rexe4 dxe4 27.Qxf6 Qc7
28.Nh6+ Kf8 29.Qh8+ Ke7 30.Nf5# 1-0


109)
[Event "19th Sigeman & Co"]
[Site "Malmo SWE"]
[Date "2011.06.13"]
[Round "5"]
[White "Hector, J."]
[Black "So, W."]
[Result "0-1"]
[WhiteElo "2588"]
[BlackElo "2667"]
[ECO "C13"]
[EventDate "2011.06.09"]
[PlyCount "62"]

1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Be7 5.e5 Nfd7 6.h4 O-O 7.Qg4 f6 8.Nf3 Rf7
9.exf6 Nxf6 10.Qg3 Nc6 11.O-O-O Qf8 12.h5 Bb4 13.Bxf6 Rxf6 14.Bd3 Bd6 15.
Ne5 Rxf2 16.Rdf1 Bxe5 17.dxe5 Rxf1+ 18.Rxf1 Qe7 19.Bg6 hxg6 20.hxg6 Nd4
21.Rf7 Qd8 22.Qf4 Nf5 23.g4 Nh4 24.Rxg7+ Kxg7 25.Qf7+ Kh6 26.Qh7+ Kg5 27.
Qh5+ Kf4 28.Ne2+ Ke3 29.g5 Nf3 30.Kd1 Qxg5 31.Qh7 Kf2 0-1


118)
[Event "Komercni Bank"]
[Site "Pardubice open"]
[Date "1996.07.12"]
[Round "1"]
[White "Shtyrenkov, V."]
[Black "Krouzel, J."]
[Result "1-0"]
[WhiteElo "2450"]
[BlackElo "2240"]
[ECO "A80"]
[EventDate "1996.??.??"]
[PlyCount "78"]

1.d4 f5 2.Nc3 d5 3.Bf4 Nf6 4.e3 e6 5.Nb5 Na6 6.c4 Bb4+ 7.Nc3 O-O 8.a3
Bxc3+ 9.bxc3 c5 10.Bd3 Qa5 11.Ne2 Bd7 12.O-O dxc4 13.Bxc4 b5 14.Ba2 c4 15.
a4 bxa4 16.Bxc4 Nd5 17.Bb3 Nb6 18.Be5 Qb5 19.Ba2 Nc4 20.Rb1 Qc6 21.Bg3
Rfc8 22.Nf4 Nc7 23.Rb4 Nb6 24.c4 Kh8 25.Nd3 Qe4 26.Ne5 Bc6 27.Nxc6 Qxc6
28.Bxc7 Rxc7 29.Qf3 a3 30.Ra1 Rac8 31.c5 Nd5 32.Bxd5 Qxd5 33.Qxd5 exd5 34.
Rxa3 Re8 35.h4 Kg8 36.g3 Kf7 37.Kg2 Kf6 38.Ra6+ Re6 39.Rba4 h6 1-0


120)
[Event "Hoogovens"]
[Site "Wijk aan Zee II"]
[Date "1988.01.??"]
[Round "1"]
[White "Nijboer, F."]
[Black "Winants, L."]
[Result "1-0"]
[WhiteElo "2375"]
[BlackElo "2465"]
[ECO "B89"]
[EventDate "1988.??.??"]
[PlyCount "63"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 Nc6 6.Bc4 e6 7.Be3 Be7 8.Qe2
a6 9.Bb3 Qc7 10.O-O-O O-O 11.Rhg1 Na5 12.g4 b5 13.g5 Nxb3+ 14.axb3 Nd7 15.
f4 b4 16.Nf5 exf5 17.Nd5 Qd8 18.exf5 Re8 19.Bd4 Bf6 20.Qxe8+ Qxe8 21.gxf6
g6 22.Ne7+ Kf8 23.Rd3 Nxf6 24.Bxf6 Qb5 25.Rgd1 Bxf5 26.Rd5 Qe2 27.Nxf5 Rc8
28.R5d2 Qe4 29.Nxd6 Rxc2+ 30.Rxc2 Qxf4+ 31.Kb1 Qxf6 32.Rc8+ 1-0


121)
[Event "Pucarevo zt"]
[Site "Pucarevo zt"]
[Date "1987.??.??"]
[Round "1"]
[White "Marjanovic, S."]
[Black "Yilmaz, T."]
[Result "1-0"]
[WhiteElo "2505"]
[BlackElo "2375"]
[ECO "C84"]
[EventDate "1987.??.??"]
[PlyCount "67"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.d4 exd4 6.O-O Be7 7.e5 Ne4 8.Nxd4
Nxd4 9.Qxd4 Nc5 10.Nc3 Nxa4 11.Qxa4 O-O 12.Bf4 b5 13.Qd4 Bb7 14.Rad1 Bc6
15.Nd5 Re8 16.Rd3 Bf8 17.Bg3 Qc8 18.Nf6+ gxf6 19.Bh4 Re6 20.Rg3+ Kh8 21.
Qg4 Bh6 22.Qxe6 fxe6 23.Bxf6+ Bg7 24.Rxg7 h5 25.Rd1 Qf8 26.Rg5+ Kh7 27.
Rxh5+ Kg6 28.Rg5+ Kf7 29.Rd4 Qh6 30.Rf4 Qh7 31.Rfg4 Kf8 32.Rg7 Qh8 33.Be7+
Ke8 34.Bb4 1-0


122)
[Event "City of Culture GM"]
[Site "Donostia ESP"]
[Date "2009.07.12"]
[Round "5"]
[White "Svidler, P."]
[Black "Karpov, Ana"]
[Result "1-0"]
[WhiteElo "2739"]
[BlackElo "2644"]
[ECO "C43"]
[EventDate "2009.??.??"]
[PlyCount "69"]

1.e4 e5 2.Nf3 Nf6 3.d4 Nxe4 4.Bd3 d5 5.dxe5 Nc6 6.O-O Bg4 7.Nc3 Nxc3 8.
bxc3 Be7 9.Bf4 Qd7 10.Rb1 Nd8 11.h3 Bh5 12.g4 Bg6 13.Bg3 Bxd3 14.cxd3 h5
15.e6 Nxe6 16.Ne5 Qc8 17.f4 h4 18.Bh2 O-O 19.g5 g6 20.f5 Nxg5 21.f6 Bd6
22.Qd2 Nxh3+ 23.Kh1 Bxe5 24.Bxe5 Kh7 25.Qg2 g5 26.Rf3 Rg8 27.Rxh3 Rg6 28.
Rf1 Qe6 29.d4 Rag8 30.Re3 c6 31.Qe2 g4 32.Bc7 Qc8 33.Re7 Rg5 34.Rxf7+ Kg6
35.Qd3+ 1-0


125)
[Event "ch-LTU"]
[Site "Vilnius LTU"]
[Date "2004.04.23"]
[Round "1"]
[White "Asauskas, H."]
[Black "Malisauskas, V."]
[Result "1-0"]
[WhiteElo "2358"]
[BlackElo "2525"]
[ECO "B86"]
[EventDate "2004.04.23"]
[PlyCount "47"]

1.e4 c5 2.Nf3 d6 3.d4 Nf6 4.Nc3 cxd4 5.Nxd4 a6 6.Bc4 e6 7.Bb3 Be7 8.g4 O-O
9.g5 Nfd7 10.Rg1 Nc5 11.Be3 Nxb3 12.axb3 Nc6 13.Nxc6 bxc6 14.e5 d5 15.Ra4
g6 16.Rh4 c5 17.Rg3 Kg7 18.Qf3 Bb7 19.Qf6+ Bxf6 20.gxf6+ Kg8 21.Rxh7 Kxh7
22.Rh3+ Kg8 23.Bh6 Qc7 24.f4 1-0


127)
[Event "Biel open"]
[Site "Biel open"]
[Date "1990.07.??"]
[Round "1"]
[White "Smagin, S."]
[Black "Sahovic, D."]
[Result "1-0"]
[WhiteElo "2550"]
[BlackElo "2370"]
[ECO "B00"]
[EventDate "1990.??.??"]
[PlyCount "45"]

1.e4 Nc6 2.d4 d5 3.e5 Bf5 4.c3 e6 5.Nd2 f6 6.f4 fxe5 7.fxe5 Nh6 8.Ndf3 Nf7
9.Ne2 Be7 10.Ng3 Bg4 11.Bd3 Ng5 12.Nxg5 Bxd1 13.Nxe6 Qb8 14.Nxg7+ Kd8 15.
Kxd1 b5 16.Ne6+ Kc8 17.Nf5 Bf8 18.Rf1 Kb7 19.Bh6 Bxh6 20.Nc5+ Kc8 21.Nxh6
Ne7 22.Be2 Ng6 23.Nf7 1-0


128)
[Event "St Petersburg vs Moscow"]
[Site "St Petersburg RUS"]
[Date "2005.06.14"]
[Round "1"]
[White "Solovjov, S."]
[Black "Kharitonov, Alexa"]
[Result "1-0"]
[WhiteElo "2473"]
[BlackElo "2515"]
[ECO "B12"]
[EventDate "2005.06.14"]
[PlyCount "53"]
[WhiteTeam "Sri Lanka"]
[BlackTeam "Littauen"]
[WhiteTeamCountry "SRI"]
[BlackTeamCountry "LTU"]

1.e4 c6 2.d4 d5 3.e5 c5 4.c4 Nc6 5.Nf3 cxd4 6.Nxd4 Nxe5 7.cxd5 Nf6 8.Nc3
a6 9.Qa4+ Bd7 10.Qb3 b5 11.Bf4 Ng6 12.Bg3 b4 13.Nc6 Bxc6 14.dxc6 bxc3 15.
Rd1 Qa5 16.Bc4 e6 17.Ke2 Bc5 18.Rhe1 cxb2 19.Qb7 Rd8 20.Rxd8+ Qxd8 21.c7
Be7 22.cxd8=Q+ Bxd8 23.Bd6 Ne7 24.Bxe7 Bxe7 25.Bxa6 g6 26.Qc8+ Bd8 27.Bb5+
1-0


130)
[Event "Leningrad"]
[Site "Leningrad"]
[Date "1934.??.??"]
[Round "1"]
[White "Belavenets, Sergey"]
[Black "Botvinnik, M."]
[Result "1/2-1/2"]
[ECO "E18"]
[EventDate "1934.??.??"]
[PlyCount "98"]

1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3 Bb7 5.Bg2 Be7 6.O-O O-O 7.Nc3 d5 8.Ne5 Qc8
9.Bf4 dxc4 10.Nxc4 Bxg2 11.Kxg2 Qb7+ 12.Kg1 Rd8 13.Qc2 Nc6 14.e3 Rxd4 15.
exd4 Nxd4 16.Qc1 Nf3+ 17.Kh1 e5 18.Be3 Ng4 19.Qc2 Nd2+ 20.Kg1 Nf3+ 21.Kh1
Nd2+ 22.Kg1 Nxc4 23.Bc1 Qf3 24.Qe2 Qxe2 25.Nxe2 e4 26.b3 Nce5 27.h3 Nf3+
28.Kg2 Nge5 29.Be3 f5 30.Rfd1 Kf7 31.Bd4 Nd3 32.Bc3 Rd8 33.Kf1 Bd6 34.Nc1
Nc5 35.Ne2 Nd3 36.Nc1 Nxc1 37.Raxc1 g6 38.Bb2 Ke6 39.Ke2 c5 40.Rc2 Rg8 41.
b4 cxb4 42.Rc6 Rd8 43.a3 b3 44.a4 Ne5 45.Bxe5 Kxe5 46.Rc3 b2 47.Rb1 Bb4
48.Rc2 Bc5 49.Rbxb2 Rd3 1/2-1/2


131)
[Event "Hoogovens"]
[Site "Wijk aan Zee II"]
[Date "1997.01.??"]
[Round "1"]
[White "Nijboer, F."]
[Black "Dao Thien Hai"]
[Result "1/2-1/2"]
[WhiteElo "2555"]
[BlackElo "2555"]
[ECO "B93"]
[EventDate "1997.??.??"]
[PlyCount "192"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.f4 Qc7 7.Qf3 e5 8.Nb3 Be7
9.Bd3 O-O 10.O-O Nbd7 11.g4 exf4 12.g5 Ne5 13.Qxf4 Ne8 14.Nd5 Qd8 15.Bd2
Nc7 16.Nf6+ Kh8 17.Kh1 Ng6 18.Qf3 Ne5 19.Qf2 d5 20.Qh4 gxf6 21.gxf6 Bd6
22.Bh6 Ng6 23.Bg7+ Kg8 24.Qh6 Be5 25.Rae1 d4 26.Rf3 Ne8 27.Ref1 Qd6 28.Nd2
b5 29.h4 Bg4 30.h5 Bxf3+ 31.Nxf3 Bf4 32.hxg6 Bxh6 33.gxh7+ Kxh7 34.e5+ Kg8
35.Bxh6 Qd5 36.Rg1+ Kh8 37.Rg3 Qc5 38.Rh3 Kg8 39.Rg3+ Kh8 40.Rh3 Kg8 41.
Bh7+ Kh8 42.Be4 Kg8 43.Rg3+ Kh8 44.Bxa8 Nxf6 45.Bg7+ Kh7 46.Ng5+ Kxg7 47.
Ne6+ Kh6 48.Nxc5 Nh5 49.Rf3 Rxa8 50.Rxf7 Rc8 51.b4 a5 52.a3 axb4 53.axb4
Kg6 54.Rf2 Re8 55.Nd3 Kg5 56.Kg2 Rc8 57.e6 Re8 58.Re2 Kf6 59.Kf3 Rxe6 60.
Re4 Rxe4 61.Kxe4 Ke6 62.Kxd4 Kd6 63.Nc5 Nf4 64.Ne4+ Kc6 65.Ke5 Nd5 66.c3
Ne3 67.Nf6 Nc4+ 68.Ke6 Nb6 69.Ke5 Nc4+ 70.Kf5 Kd6 71.Ke4 Nb6 72.Kd4 Kc6
73.Ng4 Kd6 74.Ne3 Kc6 75.Ke5 Nd7+ 76.Ke6 Nb6 77.Nf5 Na4 78.Nd4+ Kb6 79.Ne2
Kc6 80.Ke5 Kc7 81.Kd5 Kd7 82.Kd4 Kd6 83.Ng3 Kc6 84.Nf5 Nb6 85.Ng7 Kd6 86.
Ne8+ Kc6 87.Nf6 Kd6 88.Ne4+ Kc6 89.Nc5 Kd6 90.Nb3 Kc6 91.Ke5 Na4 92.Na5+
Kb6 93.Kd4 Nb2 94.c4 bxc4 95.Nxc4+ Kb5 96.Nxb2 Kxb4 1/2-1/2


135)
[Event "USSR"]
[Site "USSR"]
[Date "1978.??.??"]
[Round "1"]
[White "Gufeld, E."]
[Black "Osnos, Viacheslav"]
[Result "1-0"]
[ECO "B29"]
[EventDate "1978.??.??"]
[PlyCount "65"]

1.e4 c5 2.Nf3 Nf6 3.e5 Nd5 4.d4 cxd4 5.Qxd4 e6 6.Bc4 Nc6 7.Qe4 d6 8.O-O
dxe5 9.Nxe5 Qc7 10.Nf3 Nf6 11.Qe2 Bd6 12.Re1 Ng4 13.h3 Nge5 14.Nxe5 Bxe5
15.Nd2 O-O 16.Nf3 Nd4 17.Nxd4 Bxd4 18.Rd1 Bc5 19.b3 Bd7 20.Bb2 Rfd8 21.Qg4
Bf8 22.Bf6 Re8 23.Bd3 Bc6 24.Bxh7+ Kxh7 25.Qh5+ Kg8 26.Rd4 gxf6 27.Rg4+
Bg7 28.Qh6 Kf8 29.Rxg7 Rac8 30.Qh7 b5 31.Rd1 Bd5 32.c4 bxc4 33.bxc4 1-0


139)
[Event "Capablanca Mem Mixto"]
[Site "Havana CUB"]
[Date "2002.05.07"]
[Round "2"]
[White "Zambrana, O."]
[Black "Pina, S."]
[Result "1-0"]
[WhiteElo "2389"]
[BlackElo "2371"]
[ECO "B89"]
[EventDate "2002.05.06"]
[PlyCount "43"]
[WhiteTeam "Sri Lanka"]
[BlackTeam "Littauen"]
[WhiteTeamCountry "SRI"]
[BlackTeamCountry "LTU"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 Nc6 6.Bc4 e6 7.Be3 Be7 8.Qe2
a6 9.O-O-O Qc7 10.Bb3 O-O 11.Rhg1 b5 12.g4 Nd7 13.Nf5 Nc5 14.Bd5 Bb7 15.g5
b4 16.Qh5 Ne5 17.Rg3 exf5 18.exf5 bxc3 19.g6 cxb2+ 20.Kb1 h6 21.gxf7+ Rxf7
22.Rxg7+ 1-0


141)
[Event "Budapest"]
[Site "Budapest"]
[Date "1921.09.??"]
[Round "1"]
[White "Alekhine, A."]
[Black "Sterk, K."]
[Result "1-0"]
[ECO "D37"]
[EventDate "1921.??.??"]
[PlyCount "59"]

1.d4 d5 2.Nf3 e6 3.c4 Nf6 4.Nc3 Nbd7 5.e3 Bd6 6.Nb5 Be7 7.Qc2 c6 8.Nc3 O-O
9.Bd3 dxc4 10.Bxc4 c5 11.dxc5 Bxc5 12.O-O b6 13.e4 Bb7 14.Bg5 Qc8 15.Qe2
Bb4 16.Bd3 Bxc3 17.Rfc1 Nxe4 18.Bxe4 Bxe4 19.Qxe4 Nc5 20.Qe2 Ba5 21.Rab1
Qa6 22.Rc4 Na4 23.Bf6 Rfc8 24.Qe5 Rc5 25.Qg3 g6 26.Rxa4 Qd3 27.Rf1 Rac8
28.Rd4 Qf5 29.Qf4 Qc2 30.Qh6 1-0


144)
[Event "96th ch-GBR"]
[Site "Torquay ENG"]
[Date "2009.07.31"]
[Round "5"]
[White "Summerscale, A."]
[Black "Jones, G."]
[Result "0-1"]
[WhiteElo "2454"]
[BlackElo "2554"]
[ECO "E99"]
[EventDate "2009.07.27"]
[PlyCount "64"]
[WhiteTeamCountry "SRI"]
[BlackTeamCountry "LTU"]

1.Nf3 Nf6 2.c4 g6 3.Nc3 Bg7 4.d4 O-O 5.e4 d6 6.Be2 e5 7.O-O Nc6 8.d5 Ne7
9.Ne1 Nd7 10.Be3 f5 11.f3 f4 12.Bf2 g5 13.a4 Rf6 14.a5 Rh6 15.Kh1 Nf6 16.
c5 Qe8 17.Ra3 Qh5 18.Bg1 Qh4 19.Bb5 Nh5 20.Ne2 Ng3+ 21.Nxg3 fxg3 22.Nd3
Ng6 23.c6 Nf4 24.Nxf4 Qxf4 25.Qe1 bxc6 26.Bc4 c5 27.Rb3 Bd7 28.Qe3 Rxh2+
29.Bxh2 Qh4 30.Qg1 Rf8 31.Rb7 Rf4 32.Rxc7 Qh6 0-1


145)
[Event "Ubeda open"]
[Site "Ubeda open"]
[Date "1997.01.24"]
[Round "1"]
[White "Shulman, Y."]
[Black "Marciano, D."]
[Result "1-0"]
[WhiteElo "2555"]
[BlackElo "2485"]
[ECO "C25"]
[EventDate "1997.??.??"]
[PlyCount "51"]

1.e4 e5 2.Nc3 Nc6 3.f4 exf4 4.Nf3 g5 5.h4 g4 6.Ng5 h6 7.Nxf7 Kxf7 8.Bc4+
d5 9.Bxd5+ Kg7 10.d4 Nf6 11.Bxf4 Bb4 12.Bxc6 bxc6 13.O-O Rf8 14.Qd2 Ng8
15.Be5+ Kh7 16.Rxf8 Qxf8 17.Rf1 Qe7 18.Qf4 Be6 19.Nd5 Bd2 20.Qxd2 cxd5 21.
Qf4 c6 22.exd5 cxd5 23.c4 Qd7 24.h5 Ne7 25.Qf6 Rg8 26.Qf7+ 1-0


146)
[Event "54th Reggio Emilia"]
[Site "Reggio Emilia ITA"]
[Date "2011.12.31"]
[Round "5"]
[White "Morozevich, A."]
[Black "Vitiugov, N."]
[Result "1-0"]
[WhiteElo "2762"]
[BlackElo "2729"]
[ECO "E39"]
[EventDate "2011.??.??"]
[PlyCount "81"]

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 c5 5.dxc5 O-O 6.a3 Bxc5 7.Nf3 b6 8.e4 Nc6
9.b4 Nd4 10.Qd2 Nxf3+ 11.gxf3 Be7 12.Rg1 Kh8 13.Bb2 a5 14.b5 d6 15.O-O-O
Rg8 16.Kb1 Bb7 17.h4 Qc7 18.h5 h6 19.Na4 e5 20.Qe3 Bd8 21.Bd3 Nd7 22.f4
Bf6 23.fxe5 Bxe5 24.Bxe5 Nxe5 25.Nxb6 Rae8 26.Nd5 Bxd5 27.exd5 Nxd3 28.
Qxd3 Re5 29.Rde1 Rxh5 30.Qd4 Qc8 31.Kb2 Kh7 32.Re7 Rf5 33.f4 g5 34.fxg5
Rgxg5 35.Rge1 Rg4 36.Qd3 Kg7 37.Qc3+ Kg6 38.b6 Qc5 39.b7 Rg2+ 40.Ka1 Rf3
41.b8=Q 1-0


150)
[Event "London"]
[Site "London"]
[Date "1984.??.??"]
[Round "?"]
[White "Polugaevsky, Lev"]
[Black "Torre, Eugenio"]
[Result "1-0"]
[WhiteElo "2615"]
[BlackElo "2565"]
[ECO "D19"]
[EventDate "1984.??.??"]
[PlyCount "65"]

1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.e3 e6 7.Bxc4 Bb4 8.O-O O-O
9.Qe2 Nbd7 10.e4 Bg6 11.Bd3 Bh5 12.Bf4 Re8 13.e5 Nd5 14.Nxd5 cxd5 15.h3
Be7 16.Rfc1 a6 17.Rc3 Bxf3 18.Qxf3 Nb8 19.Bxh7+ Kxh7 20.Qh5+ Kg8 21.Rg3 g6
22.Rxg6+ fxg6 23.Qxg6+ Kh8 24.Qh6+ Kg8 25.Qxe6+ Kh8 26.Qh6+ Kg8 27.Qg6+
Kh8 28.Qh5+ Kg8 29.Bh6 Bf8 30.Qg6+ Kh8 31.Bxf8 Rxf8 32.Qh6+ Kg8 33.Ra3 1-0


151)
[Event "Sydney International Open"]
[Site "Parramatta AUS"]
[Date "2012.04.11"]
[Round "1.2"]
[White "Sengupta, D."]
[Black "Zelesco, Karl"]
[Result "1-0"]
[WhiteElo "2572"]
[BlackElo "2048"]
[ECO "B12"]
[EventDate "2012.04.11"]
[PlyCount "35"]

1.e4 c6 2.d4 d5 3.e5 Bf5 4.h4 h5 5.Bg5 Qb6 6.Bd3 Bxd3 7.Qxd3 Qxb2 8.e6
Qxa1 9.Qb3 Qxd4 10.Qxb7 Qe5+ 11.Be3 Qxe6 12.Qxa8 Qe5 13.Nf3 Qb2 14.O-O Nf6
15.Bd4 Qb4 16.a3 Qd6 17.Be5 Qd8 18.Qxb8 1-0


154)
[Event "ch-Euro Youth b18"]
[Site "Albena BUL"]
[Date "2011.09.18"]
[Round "7.1"]
[White "Grandelius, N."]
[Black "Raznikov, D."]
[Result "1-0"]
[WhiteElo "2536"]
[BlackElo "2433"]
[ECO "A30"]
[EventDate "2011.09.11"]
[PlyCount "131"]

1.c4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 g6 5.g3 Bg7 6.Nc2 d6 7.Bg2 Be6 8.Ne3
Qd7 9.Nd5 Rc8 10.O-O Bh3 11.Nbc3 Bxg2 12.Kxg2 Ne5 13.b3 Nf6 14.Nxf6+ Bxf6
15.Nd5 Bg7 16.Bg5 Nc6 17.Rc1 h6 18.Be3 O-O 19.Qd2 Kh7 20.Rfd1 Rfd8 21.Qd3
e6 22.Nf4 Qe7 23.Qe4 Kg8 24.Bd2 a6 25.Bc3 d5 26.cxd5 exd5 27.Qxe7 Nxe7 28.
Ba5 Rxc1 29.Rxc1 Rd7 30.Bb6 Nc6 31.Nd3 Re7 32.Kf1 h5 33.Rc5 Rd7 34.Nf4 Ne7
35.Rc2 Be5 36.Nd3 Bd6 37.Ke1 f6 38.Bc5 Bxc5 39.Rxc5 b6 40.Rc2 a5 41.Nf4
Kf7 42.h4 Ra7 43.Rd2 Rc7 44.Kd1 Rc5 45.Rd4 Ke8 46.Kd2 Kf7 47.a3 g5 48.b4
axb4 49.axb4 Rb5 50.Nd3 Nf5 51.e3 Nxd4 52.exd4 Kg6 53.Kc3 Kf5 54.f3 g4 55.
Kb3 gxf3 56.Nf2 Kg6 57.Ka4 Rxb4+ 58.Kxb4 f5 59.Kb5 f4 60.gxf4 Kf5 61.Kxb6
Kxf4 62.Kc5 Kg3 63.Nd3 Kxh4 64.Kxd5 Kg3 65.Ke4 h4 66.Ke3 1-0

[mcostalba]

Thanks Vincent!

It will take me a while to go through all that positions

BTW I really like the way you look for hard position: you don't search for hours, just few minutes but then repeat the run 3-4 times. This is a smart way to test because engines once they found a good PV tend to stick with it as long as the PV does not fail low, so they can oversight the winning move. Instead you take advantage of the un-deterministic behavior of a multi-thread search to raise the chance to find the best move and reduce oversights. IMO this is more effective than searching for long hours.

I am thinking to something even more effective to filter out real hard positions from tactical shots that the engine somehow oversights. I would call it double blind test (I really don't think it is new, very probably already in use, but just I don't know it).

Here the test is first to search for a minute or so on the position, just to warm up and get a baseline score. Of course the engine should not find the correct move, then you force the correct move and let the engine search for another minute or so. If the engine raises immediately the score then the position is not really difficult and it was just an oversight by the engine. If instead the score remains more or less similar to the baseline then perhaps this position is unsound or this is a _really_ hard position, so you just let the engine search some longer, if position score remains unchanged then this position is unsound, if instead it slowly climbs up sensibly higher then baseline, then you have found a super strong and hard one! And not only for the engine under test, but very possibly for all the engines.

[peter]

I found 45 references for this file http://home.scarlet.be/vincentlejeune/c ... 6beta6.epd

Thanks for the pgns too, Vincent, but one thing more I'd need now to connect those to your epds, the move- numbers of the positions in the games.

[Vinvin]

Thanks Vincent!

It will take me a while to go through all that positions

Great ! I hope it will be useful to improve Stockfish.
I spent hundreds of hours on them (and my computers thousand of hours).

BTW I really like the way you look for hard position: you don't search for hours, just few minutes but then repeat the run 3-4 times. This is a smart way to test because engines once they found a good PV tend to stick with it as long as the PV does not fail low, so they can oversight the winning move. Instead you take advantage of the un-deterministic behavior of a multi-thread search to raise the chance to find the best move and reduce oversights. IMO this is more effective than searching for long hours.

In the beginning it's a case of ease for me, instead of dividing the suite in 6 part then configuring 6 engines, I chose to run multi-thread despite the fact the result are not reproducible.
Then it became a case a serendipity (discovering new things by luck) , the results show interesting things :
- sometimes the engine find 1 time the solution on 4 runs, that show the solution is reachable by the engine but not easily.
- sometimes the engine find the solution 50% of time, that show there's a second move is very close. Or the solution get fast 0.00 as another move -> not a good test move.
- sometimes the engine stick with a bad move 1 time on 4 runs, that could show a bad behavior by the engine that can't change the best line easily.

I am thinking to something even more effective to filter out real hard positions from tactical shots that the engine somehow oversights. I would call it double blind test (I really don't think it is new, very probably already in use, but just I don't know it).

Here the test is first to search for a minute or so on the position, just to warm up and get a baseline score. Of course the engine should not find the correct move, then you force the correct move and let the engine search for another minute or so. If the engine raises immediately the score then the position is not really difficult and it was just an oversight by the engine.

That would dismiss positions where the engine has a hard time to find the first move ! Stockfish has this problem for long time, if it would be easy to solve, I suppose it would have been already done.
That reminds me the time where Vasik Rajlich decided to make (and successfully did) Rybka stronger in tactic (between version 2.3.2a and 3).
- http://rybkaforum.net/cgi-bin/rybkaforu ... 6#pid38526
- http://rybkaforum.net/cgi-bin/rybkaforu ... 5#pid23405
- http://rybkaforum.net/cgi-bin/rybkaforu ... 6#pid43976

If instead the score remains more or less similar to the baseline then perhaps this position is unsound or this is a _really_ hard position, so you just let the engine search some longer, if position score remains unchanged then this position is unsound, if instead it slowly climbs up sensibly higher then baseline, then you have found a super strong and hard one! And not only for the engine under test, but very possibly for all the engines.

Here are a couple of "very hard" by your definition, where Stockfish has no clue at all :

Here the engine has to see the position is closed and it's impossible to win unless sacrificing a rook to win :
1r6/4k3/r2p2p1/2pR1p1p/2P1pP1P/pPK1P1P1/P7/1B6 b - - bm Rxb3;

Draw by fortress :
2b1r3/r2ppN2/8/1p1p1k2/pP1P4/2P3R1/PP3PP1/2K5 w - - bm Nd6;

Zugzwang at the end of the best line :
2r5/prkpR1p1/2p1ppK1/P1p1N1B1/P1P1P3/8/8/8 w - - bm Bf4;

Long king walk :
6b1/5p2/1p3Bp1/1P3pP1/5P2/pp1B2K1/pr4P1/k7 w - - bm Kh2;

[mcostalba]

I have just finished testing with Double Blind Test (DBT) the full suite of 160 hard positions provided by Vincent. I have used current Stockfish modified by me to run automatically the DBT test on a epd file without need of human supervisor, so it ran overnight.

Because I want to validate the method, I run it on my slow laptop Intel Core i5-3230M @ 2.60GHz, with only 2 threads at only 120sec per position.

Code: Select all

- Total speed running with 2 threads: 2.3 Mnps
- Time per position; baseline 120 sec + forced bm 120 sec

So just 4 total minutes per position on a slow laptop!

After DBT only 30 positions out of the original 160 survived!

I have further split the positions in 2 groups, according to their Double Blind Index (DBI):

Code: Select all

DBI 1: Score with forced best move is similar or slightly less than baseline

DBI 2: Score with forced best move is still sensibly lower than baseline, so position is harder.

So the winners are...

Code: Select all

DBI 2 (super hard)
1b6/2p5/1kB5/1PN5/8/3K4/8/q7 w - - bm Nb3; DBI 2
1r3rk1/5p1p/p2pb1p1/3Np1P1/2pRPR2/qP2Q1N1/P1PK3P/8 w - - bm Nf5; c1 "diff=5"; DBI 2
2r1r1k1/4bppp/1q4n1/3pP3/p1pP4/PnR2NBP/1P4P1/1B1QR2K w - - bm e6; c1 "diff=8"; DBI 2
3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - bm Nd4; c1 "diff=10"; DBI 2
3k4/4pp2/n2n4/5BN1/3N4/b7/4K3/8 w - - bm Nxf7+; c1 "diff=8"; DBI 2
4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - bm f4; id "arasan19.189"; c0 "Šachová skladba 2011-12, 1st Prize"; DBI 2
4k1br/1K1p1n1r/2p2pN1/P2p1N2/2P3pP/5B2/P2P4/8 w - - id ?; bm Kc8; DBI 2
4q1kr/p6p/1prQPppB/4n3/4P3/2P5/PP2B2P/R5K1 w - - bm Qxe5; c1 "diff=10"; DBI 2
5nr1/2Pp2pk/3Pp1p1/4P1P1/6P1/5K2/8/7n w - - id ?; bm c8=N; DBI 2
8/1p2b3/6k1/5p2/p2NbP1p/P1B1P1p1/1P5P/6K1 w - - bm h3; c0 "fortress From Smirin-HIARCS"; c1 "diff=10"; DBI 2
8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - bm Nf6+; c0 "study by Van Breukelen"; DBI 2
8/8/4kpp1/3p1b2/p6P/2B5/6P1/6K1 b - - bm Bh3; c1 "diff=7"; DBI 2
q7/b1p5/kp1p4/p2PN3/PPP5/1K6/8/5B2 w - - bm c5+; c1 "diff=7"; DBI 2


DBI 1
1nrqr3/1b4bk/pp3pp1/3pPp1p/P1pP1P1P/2P1BN2/1PB2QP1/R4RK1 w - - id ?; bm Nh2; g4; DBI 1
1rb2r1k/3p1pp1/p3p2p/1p2P3/4q3/1N2B1R1/PPP1N1P1/2KR1B2 w - - bm Nf4; DBI 1
2b1rk2/5p2/p1P5/2p2P2/2p5/7B/P7/2KR4 w - - bm f6; id "arasan19.41"; c0 "study by Smyslov"; DBI 1
2bq1b2/1p3k2/1r1p1p1p/pNpP1PpP/P1P3P1/6B1/1P5Q/2K1R3 w - - bm Re6; DBI 1
2q2r1k/p1p1b1pp/br1p1n2/2p1N1BP/Q1P1P3/8/PP1N1PP1/2KR3R w - - id ?; bm Ng6+; DBI 1
2r5/prkpR1p1/2p1ppK1/P1p1N1B1/P1P1P3/8/8/8 w - - bm Bf4; c1 "diff=9"; DBI 1
6R1/8/2pB3k/2P4p/5p1q/5P2/4P1K1/8 w - - bm Bf8+; c1 "diff=8"; DBI 1
6b1/5p2/1p3Bp1/1P3pP1/5P2/pp1B2K1/pr4P1/k7 w - - bm Kh2; c1 "diff=10"; DBI 1
6k1/p7/8/4B3/Pp3p1P/qP5P/P1Rb2K1/8 w - - bm Kf3; c1 "diff=10"; DBI 1
7q/b1p5/1p1Npkb1/pPP2ppP/P1P5/3B2P1/5P1R/K3R3 w - - bm hxg6; c1 "diff=10"; DBI 1
8/5p2/N1p3p1/3pP1P1/7P/2kP4/Pb6/7K w - - bm h5; c1 "diff=7"; DBI 1
8/bp4Pk/4KB2/R6p/2pNp1P1/p7/3p1Pnq/2r5 w - - id ?; bm Nc6; DBI 1
q1r5/k3ppp1/2R5/PP1KP2r/2p4Q/2p1p3/5pP1/3R4 w - - id ?; bm Qd4+; DBI 1
r1b2rk1/2q1bppp/p2pp3/2n3PQ/1p1BP3/1BN5/PPP2P1P/2KR2R1 w - - bm Bf6; c1 "diff=7"; DBI 1
r1bqkb1r/ppp3pp/n3pn2/1N1p1p2/3P1B2/4P3/PPP2PPP/R2QKBNR w KQkq - bm c4; DBI 1
r2qrbk1/1b3p2/3p2pB/1p1P1N2/1np1P3/5NRP/1P3PP1/1B1Qn1K1 w - - id ?; bm N3h4; DBI 1
r2r2k1/pqp1bppp/1pn1pn2/8/2NP1B2/2N1P1P1/PPQ2P1P/R4RK1 b - - bm Rxd4; DBI 1

Vincent, it would be great if you could double check these positions (at least the DBI 2 group) with your multiple-run method to verify these are really hard and DBT works.


P.S: I understand your point that DBT don't find positions where SF has difficult to select the best move, but OTH if this method works then, for how it is designed, I think it should be able to find positions that are very hard for any engine, not only for the one under test.

[peter]

one thing more I'd need now to connect those to your epds, the move- numbers of the positions in the games.

Even better of course would be, if the sources of the positions were written to the epds, but one thing seems even more important to me than that: numbers for the positions themselves within the set.

Otherwise I always have to load it wholly into a GUI to let the numbering be done in that way again and even then it's not always easy to find the ones in this and other threads out of the set. If there were fixed numbers those could be given in postings too.

[peter]

I
I have further split the positions in 2 groups, according to their Double Blind Index (DBI):

Code: Select all

DBI 1: Score with forced best move is similar or slightly less than baseline

DBI 2: Score with forced best move is still sensibly lower than baseline, so position is harder.

Although I always liked the method of Forward-Backward and looking at the evals' relations before and after, to test the engines and the positions simultaneously, I yet don't see how you want to regiment that for an automated test.
Explicit for a single ply of a best line, how much should the difference (or as for my pov much better the quotient) of the evals be, to call it solved or unsolved, a hard or a less hard position?
Doesn't it depend on engine and position almost as much as for one ply less without the Backward?
I always thought there should be best lines or test-lines of position- dependent lenghtes given to be judged in Forward-Backward-comparison, but I don't see how to automate that neither and the main problem of positional testing remains anyhow:
the outcome always is and will be position-dependent, as many positions of different kind you take, the tested playing strength has nothing to do with so called "overall playing strength", which is an illusion anyhow anyway, as for engine-engine-game-playing testing especially too, I'am used to talk about Ellousion.


I like positional testing very much, but I don't care for "overall playing strength" at all, it's something that can't be tested without the principally same bias of positional testing: you always have to start the games from given positions too.
That's so as for engines as well as for human players, their strength depends on their opening- repertoire and on their opponents mainly too.
As for engines we have this second one problem of intransitivity in game-playing more and more too, the more engines of the more different strength and the more engines of almost equal strength arise.

So why not stick to single positions always only as for positional testing and get the maximum of information out of the engines' output with and without Forward-Backward of well analysed test-lines and the maximum of information out of the to be expected and to be compared relations of the evals before and after Forward-Backward of test-lines, much more than of single numeric evals and times to "solution" gotten by stand-alone computing of the stand-alone positions

[Eelco de Groot]

I have found the full game of one of the 2 hard positions

http://chess-db.com/public/game.jsp?id= ... 1904.27155

Here is the pgn, the move of the puzzle is the move 50 Nd3:

[pgn][Event "ch-European Youth b18"]
[Site "?"]
[Date "2011.09.18"]
[Round "?"]
[White "Grandelius, Nils"]
[Black "Raznikov, Danny"]
[ECO "A30"]
[WhiteElo "2536"]
[BlackElo "2433"]
[Result "1-0"]

1. c4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. g3 Bg7 6. Nc2 d6 7. Bg2 Be6 8. Ne3 Qd7 9. Nd5 Rc8 10. O-O Bh3 11. Nbc3 Bxg2 12. Kxg2 Ne5 13. b3 Nf6 14. Nxf6+ Bxf6 15. Nd5 Bg7 16. Bg5 Nc6 17. Rc1 h6 18. Be3 O-O 19. Qd2 Kh7 20. Rfd1 Rfd8 21. Qd3 e6 22. Nf4 Qe7 23. Qe4 Kg8 24. Bd2 a6 25. Bc3 d5 26. cxd5 exd5 27. Qxe7 Nxe7 28. Ba5 Rxc1 29. Rxc1 Rd7 30. Bb6 Nc6 31. Nd3 Re7 32. Kf1 h5 33. Rc5 Rd7 34. Nf4 Ne7 35. Rc2 Be5 36. Nd3 Bd6 37. Ke1 f6 38. Bc5 Bxc5 39. Rxc5 b6 40. Rc2 a5 41. Nf4 Kf7 42. h4 Ra7 43. Rd2 Rc7 44. Kd1 Rc5 45. Rd4 Ke8 46. Kd2 Kf7 47. a3 g5 48. b4 axb4 49. axb4 Rb5 50. Nd3 Nf5 51. e3 Nxd4 52. exd4 Kg6 53. Kc3 Kf5 54. f3 g4 55. Kb3 gxf3 56. Nf2 Kg6 57. Ka4 Rxb4+ 58. Kxb4 f5 59. Kb5 f4 60. gxf4 Kf5 61. Kxb6 Kxf4 62. Kc5 Kg3 63. Nd3 Kxh4 64. Kxd5 Kg3 65. Ke4 h4 66. Ke3

1-0[/pgn]

Stockfish and komodo need the nullmove-pruning to be switched off for this position, Houdini gets it with default parameters too btw

Maybe it's more an eval problem here than Zugzwang. White does not have any immediate threats after having to give one rook (by denying it square d3, it has to place the knight there... So the extra move in Nullmove does not help in a short search (search with extra free move or in verification search). It is like a delayed sacrifice, because White can get the other rook after a kingwalk, and then he is winning, but all those king moves are quiet and prone to LMP (Late Move Pruning) and LMR.

It is a nice position because both rooks have zero squares to go to, not exactly zero mobility in Stockfish eval but all the squares they can go to are covered by the opponent's pieces. The rooks get penalties for low mobility but increasing this penalty, on the very low end of mobility range, never worked. The second rook is also not under immediate threat. You can try steering the kings toward it, but in case the king is needed to protect or attack passed pawns, it probably is not such a good idea. But maybe a smaller bonus will help, and passed pawns together with zero mobilty pieces are possibly rare enough that you can do it.

With the latest Rainbow Serpent I tried to give this bonus and it helps a little bit I think, although I have only tried it one run. All the search changes I tried were no good, so this looks more like a possible case for evaluation. It may be that the bonus I have is slightly asymmetric, (it is makeshift), but I hope that is not a very big problem. If the bonus still helps on the Nullmove side of search, that it is slightly asymmetric in some cases to the side that has a large advantage because of temporary extra material (the first rook in this case) is not so big a problem, the advantage will still be large.

[d]8/4nk2/1p3p2/1r1p2pp/1P1R1N1P/6P1/3KPP2/8 w - -

Engine: Rainbow Serpent 20160903_011 MP (i7 6700, 4 threads, 512 MB)
Latest change: makeshift bonus for moving king in the endgame to a trapped piece (and some extra penalty if our trapped piece is attacked, but this does not help much I think, it comes too late)
by T. Romstad, M. Costalba, J. Kiiski, G. LInscott

26/13 0:01 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (15.492.765) 9288

27/13 0:02 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (21.319.505) 9205

28/13 0:03 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (36.229.610) 9192

29/13 0:05 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (51.820.675) 9050

30/13 0:06 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (59.935.981) 9033

31/13 0:13 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (119.471.175) 9020

32/13 0:19 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (176.645.677) 9106

33/13 0:31 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (286.424.782) 9199

34/13 0:33 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (312.253.138) 9189

35/13 0:52 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (480.479.915) 9232

36/13 1:15 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (692.456.979) 9230

37/13 1:24 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (776.687.922) 9239

38/13 1:59 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (1.111.982.822) 9277

39/13 2:57 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (1.654.177.274) 9329

40/13 4:30 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (2.547.414.265) 9413

41/13 15:20 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (8.584.868.332) 9328

42/37 17:37 +0.08++ 50.Nd3 (9.866.703.348) 9333

42/37 18:11 +0.16++ 50.Nd3 (10.199.455.303) 9341

42/37 18:45 +0.28++ 50.Nd3 (10.523.006.977) 9347

42/39 19:23 +0.45++ 50.Nd3 (10.883.319.094) 9353

42/44 20:23 +0.68++ 50.Nd3 (11.450.687.306) 9358

42/44 22:54 +0.98++ 50.Nd3 (12.870.547.521) 9365

42/44 25:43 +1.39++ 50.Nd3 (14.453.413.382) 9366

42/44 29:03 +1.91++ 50.Nd3 (16.327.550.336) 9362

42/46 31:52 +2.58++ 50.Nd3 (17.897.036.990) 9359

42/79 64:51 +3.44++ 50.Nd3 (36.975.766.696) 9500

42/93 104:46 +4.09 50.Nd3 Nc6 51.e3 Ke6 52.Kc3 Kf5
53.f3 Na5 54.bxa5 bxa5 55.Ra4 Ke6
56.Ra2 Rb1 57.Rxa5 Rg1 58.Ra6+ Kf5
59.hxg5 Kxg5 60.f4+ Kf5 61.Nb4 Rxg3
62.Nxd5 Ke4 63.Kc4 (59.175.204.473) 9412

best move: Nf4-d3 time: 104:56.000 min n/s: 9.412.552 nodes: 59.257.347.764


Not very good but without the bonus, best I can do is 93 minutes:


8/4nk2/1p3p2/1r1p2pp/1P1R1N1P/6P1/3KPP2/8 w - -

Engine: Rainbow Serpent 20160903_002 MP (512 MB)
by T. Romstad, M. Costalba, J. Kiiski, G. Linscott

27/10 0:01 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (14.222.318) 9418

28/10 0:02 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (22.523.274) 9314

29/10 0:05 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (49.469.394) 9244
.
.
.
41/10 14:56 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (8.645.206.422) 9642

42/10 20:03 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (11.616.419.977) 9651

43/10 25:29 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (14.785.507.752) 9664

44/10 33:05 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (19.302.987.781) 9723

45/10 48:46 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (28.506.056.149) 9740

46/10 58:20 0.00 50.hxg5 fxg5 51.Nxh5 Nc6 52.Rd3 Ne5
53.Rd4 Nc6 (34.153.542.799) 9756

47/35 93:24 +0.08++ 50.Nd3 (54.952.649.838) 9804

47/35 94:28 +0.16++ 50.Nd3 (55.590.504.346) 9806

47/47 97:28 +0.28++ 50.Nd3 (57.358.630.306) 9806

47/47 100:02 +0.45++ 50.Nd3 (58.898.865.234) 9812

47/49 105:33 +0.68++ 50.Nd3 (62.168.380.722) 9815

47/49 113:28 +0.98++ 50.Nd3 (66.785.167.871) 9808

47/49 123:47 +1.39++ 50.Nd3 (72.797.656.010) 9800

47/49 138:05 +1.91++ 50.Nd3 (81.112.492.406) 9790

47/49 153:16 +2.58++ 50.Nd3 (89.861.248.628) 9771

47/49 175:51 +3.44++ 50.Nd3 (102.953.984.925) 9757

47/85 371:26 +4.54++ 50.Nd3 (216.981.441.371) 9735

47/86 615:50 +4.85 50.Nd3 Nf5 51.e3 Nd6 52.Kc2 Ne4
53.Nc1 Nxf2 54.Ne2 Ne4 55.Nc3 Nxg3
56.Nxb5 Nf5 57.Rd2 Nxe3+ 58.Kd3 Nc4
59.Re2 Ne5+ 60.Kd4 gxh4 61.Kxd5 Kg6
62.Nd4 Ng4 63.Nf3 (354.116.771.738) 9583

best move: Nf4-d3 time: 646:45.937 min n/s: 9.583.611 nodes: 366.181.934.877