analysis of 1.e4 e5 2.Nf3 f6

[Uri Blass]

So it seems that the main goes like: 1.e4 e5 2.Nf3 f6 3.Nxe5 Qe7 4.Nf3 d5 5.d3 and now black has a choice:
5...dxe4 6.dxe4 Qxe4
5...Nc6
5...Be6

So if we want to refute the opening - and I belive that there is a refutation - we should analyse these three positions to a great depth.

Note that after 5...dxe4 6.dxe4 Qxe4 it's not that obvious that 7.Be2 is the best cause there is also 7.Be3.

How much of a refutation do you want after two moves?! An evaluation of +1.86 (which must include SF's default contempt) certainly suggests that this defense sucks.

In any case, I'm searching the position below, just to confirm that SF-dev prefers 7.Be2.

[d]rnb1kbnr/ppp3pp/5p2/8/4q3/5N2/PPP2PPP/RNBQKB1R w KQkq - 0 7

I get your point Louis but there is a difference between 'much worse' and 'lost'. It's clear that black is much worse here but is he lost? This is what Uri asked in the first post, I belive. There are many opening positions where engine gives +1.80 and later it occurs that it's not possible to convert this adventage into win.

I believe that engines are relatively weak in positional understanding and for some reason in winning positions with a lot of pawns they have problems to see that they can increase their advantage significantly.

score at depth 44 is only 11.94 when already score at depths 5-6 is 12.01 and the worst score in the analysis is 11.77(when I ignore depth 2).
Stockfish cannot see even that white wins 1/4 pawn in a reasonable time.


[d]rnb1kbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

Stockfish_18081218_x64_modern:
1/1 00:00 57 10k +11.81 1.Nc3
2/2 00:00 137 20k +11.76 1.Nc3 b6
3/3 00:00 327 41k +11.90 1.Nc3 c6 2.Ne4
4/4 00:00 794 88k +11.94 1.Nf3 c6 2.Nc3 e6
5/5 00:00 2k 160k +12.01 1.Nf3 Nf6 2.Nc3 e6 3.Ne5 Na6
6/6 00:00 3k 249k +12.01 1.Nf3 Nf6 2.Nc3 e6 3.Ne5 Na6
7/7 00:00 5k 349k +11.94 1.Nf3 Nf6 2.Nc3 e6 3.Ne5 c6 4.Rb1
8/8 00:00 17k 642k +11.87 1.e4 e6 2.Nf3 Bb4 3.Nc3 Ne7 4.Ne5 Na6
9/13 00:00 59k 1,304k +11.84 1.Nc3 Nf6 2.Nf3 e6 3.e3 Nc6 4.Bd3 Bc5 5.0-0
10/11 00:00 75k 1,507k +11.78 1.Nf3 e6 2.Nc3 Nf6 3.d3 Bb4 4.Bd2 0-0 5.Nb5 Bxd2+ 6.Qxd2
11/13 00:00 89k 1,621k +11.77 1.Nf3 e6 2.Nc3 Nf6 3.d3 Bb4 4.Bd2 0-0 5.Nb5 Bxd2+ 6.Kxd2 Nd5 7.Kc1
12/17 00:00 159k 2,033k +11.85 1.Nf3 Nc6 2.Nc3 Nf6 3.e3 d5 4.Bb5 Bd7 5.Kf1 e6 6.d4 0-0-0 7.Bd2
13/17 00:00 196k 2,149k +11.78 1.Nf3 Nc6 2.Nc3 Nf6 3.d3 e6 4.Nb5 Kd8 5.e4 Bb4+ 6.c3 Ba5 7.Bf4 Bb6
14/17 00:00 429k 2,823k +11.82 1.Nc3 Nf6 2.e4 Nc6 3.Nf3 d6 4.d4 Bg4 5.Bb5 0-0-0 6.d5 Ne5 7.Be3 Bxf3 8.gxf3
15/20 00:00 918k 3,338k +11.88 1.Nc3 e6 2.Nf3 Bb4 3.d3 Nc6 4.Bd2 Ba5 5.b3 Nge7 6.e3 0-0 7.Be2 Bb6 8.0-0
16/20 00:00 1,329k 3,356k +11.86 1.Nc3 Nf6 2.e4 Nc6 3.Nf3 d6 4.d4 Bg4 5.Be3 e6 6.Be2 d5 7.e5 Nd7 8.0-0 Bb4 9.a3
17/23 00:00 2,306k 3,436k +11.82 1.Nc3 e6 2.e4 c6 3.Qe2 Be7 4.d3 d5 5.Nf3 Nf6 6.Be3 dxe4 7.Nxe4 Nbd7 8.Nd4 0-0 9.0-0-0 Nxe4
18/23 00:00 3,007k 3,610k +11.87 1.Nc3 e6 2.e4 Nf6 3.Nf3 d6 4.Be2 Be7 5.d3 Bd7 6.e5 Nd5 7.Nxd5 exd5 8.Bf4 Nc6 9.exd6 cxd6
19/24 00:01 3,767k 3,722k +11.86 1.Nc3 e6 2.e4 c6 3.d4 d5 4.Bd3 Bb4 5.Bd2 Nd7 6.Nge2 Ne7 7.a3 Bd6 8.f3 f6 9.Be3 0-0 10.Nf4 dxe4
20/24 00:01 5,010k 3,824k +11.86 1.Nc3 e6 2.e4 d6 3.d4 Nf6 4.Nf3 Be7 5.Bf4 0-0 6.Be2 Nbd7 7.Nb5 Bd8 8.Qd3 b6 9.Nc3 Bb7 10.0-0 g6
21/26 00:01 7,298k 3,708k +11.88 1.Nc3 e6 2.e4 d6 3.d4 Nf6 4.Bd3 Bd7 5.Nge2 Nc6 6.a3 g6 7.0-0 0-0-0 8.Be3 Bg7 9.f3 b6 10.Qd2 Kb7 11.Rae1 Rc8
22/28 00:02 10,849k 3,831k +11.87 1.Nc3 e6 2.e4 c6 3.d4 d5 4.Bd3 Bb4 5.Bd2 Ne7 6.Nge2 Nd7 7.0-0 Bd6 8.Nf4 Ng6 9.Nce2 dxe4 10.Bxe4 Nxf4 11.Bxf4 Bb4
23/32 00:06 27,054k 4,043k +11.87 1.e4 Nf6 2.Nc3 d6 3.d4 e6 4.Bd3 Bd7 5.Be3 Nc6 6.f3 0-0-0 7.a3 g6 8.Nge2 b6 9.Qd2 Kb8 10.g4 h6 11.0-0 Kb7 12.Rae1 Bg7 13.Kg2 e5
24/27 00:07 28,641k 4,042k +11.86 1.e4 Nf6 2.Nc3 d6 3.d4 e6 4.Bd3 Nbd7 5.Nf3 c6 6.Bf4 b6 7.0-0 Bb7 8.Qd2 Be7 9.Rae1 Rd8 10.a3 0-0 11.g3 Ng4 12.Kg2 e5 13.dxe5 Ngxe5
25/36 00:10 44,594k 4,095k +11.90 1.e4 Nf6 2.e5 Nd5 3.c4 Nb6 4.Nc3 d6 5.exd6 exd6 6.d4 Be7 7.Nf3 f6 8.Be3 Nc6 9.c5 dxc5 10.dxc5 Nd7 11.Nd5 Bd8 12.Qb3 b6 13.cxb6 axb6
26/35 00:17 73,767k 4,118k +11.85 1.e4 e6 2.d4 c6 3.Bd3 d5 4.f3 Nf6 5.c3 dxe4 6.fxe4 c5 7.Be3 cxd4 8.cxd4 Nc6 9.Nd2 Nb4 10.Bb5+ Bd7 11.Bxd7+ Kxd7 12.Ngf3 Ng4 13.Nc4 Nxe3 14.Nfe5+ Kc8 15.Nxe3
27/35 00:33 137,367k 4,153k +11.88 1.e4 e6 2.d4 Be7 3.Nc3 d6 4.Be3 Nd7 5.Nge2 c6 6.f3 Ngf6 7.g4 h6 8.Bg2 0-0 9.Kf2 e5 10.h4 exd4 11.Nxd4 Ne5 12.g5 hxg5 13.hxg5 Nh7 14.f4
28/35 00:40 167,354k 4,174k +11.87 1.e4 e6 2.d4 Be7 3.Nc3 d6 4.Be3 Nd7 5.Nge2 a6 6.f3 b5 7.Kf2 Ngf6 8.a3 c5 9.g4 h6 10.Bg2 Bb7 11.h4 0-0-0 12.h5 cxd4 13.Nxd4 Ne5 14.Rh4 Kc7
29/34 00:51 215,553k 4,179k +11.85 1.e4 e6 2.d4 Be7 3.Nc3 d6 4.Be3 Nd7 5.Nge2 Ngf6 6.f3 h5 7.Kf2 0-0 8.Qd2 c5 9.a4 g6 10.g3 a6 11.Bg2 cxd4 12.Qxd4 Nc5 13.b4 Ncd7 14.h4 Ne5 15.Qd2 Nc4
30/36 01:11 297,188k 4,157k +11.86 1.e4 e6 2.d4 Be7 3.Nc3 d6 4.Be3 a6 5.Nf3 Nd7 6.Nd2 Ngf6 7.f4 e5 8.g4 h5 9.g5 Ng4 10.Bg1 exf4 11.Nd5 Kf8 12.Nxe7 Kxe7 13.Qf3 Ne3 14.Bxe3 fxe3 15.Qxe3 c5 16.c3 cxd4
31/39 02:08 500,575k 3,897k +11.87 1.e4 e6 2.d4 Be7 3.Nc3 Kf8 4.Bd3 c6 5.e5 d5 6.Qg4 Bd8 7.Nf3 Ne7 8.Qf4 Ng6 9.Qe3 Nd7 10.0-0 Ne7 11.Bd2 Nf5 12.Qf4 g6 13.g4 g5 14.Nxg5 Bxg5 15.Qxg5 Nxd4 16.Na4 Ke8
32/40 03:06 698,861k 3,754k +11.90 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 a6 5.f4 Nc6 6.a3 Ne7 7.Bd3 g6 8.Qe2 Bg7 9.Nf3 0-0 10.0-0-0 b6 11.e5 Nfd5 12.Nxd5 Nxd5 13.Bd2 b5 14.c3 dxe5 15.fxe5 Re8 16.Kc2 f6 17.exf6
33/38 03:28 781,800k 3,750k +11.90 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 a6 5.f4 Nc6 6.a3 Ne7 7.Nf3 g6 8.h3 d5 9.e5 Nd7 10.g4 h5 11.Bg2 hxg4 12.hxg4 Rxh1+ 13.Bxh1 Bg7 14.Bg2 b6 15.Qd2 Bb7 16.0-0-0 c5 17.b3 Bc6 18.Kb2 0-0-0 19.g5
34/42 03:55 875,949k 3,712k +11.90 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 a6 5.f4 Nc6 6.a3 Ne7 7.Nf3 g6 8.h3 h5 9.Be2 Bg7 10.0-0 Bd7 11.Qd2 Rf8 12.Bd3 Bc6 13.Qe2 0-0-0 14.Kf2 Kb8 15.Nd2 Rh8 16.e5 dxe5 17.fxe5 Nd7
35/44 08:09 1,637,260k 3,343k +11.91 1.e4 d6 2.d4 Nd7 3.f4 e6 4.Nf3 Ne7 5.c4 g6 6.Nc3 a6 7.Be3 Bg7 8.Bd3 b6 9.0-0 Bb7 10.g3 0-0 11.Qb3 Rac8 12.Kg2 Rfd8 13.Rae1 Nf6 14.Qc2 Ng4 15.Bg1 a5 16.h3 Nf6 17.d5 exd5 18.cxd5
36/48 10:46 2,167,497k 3,355k +11.91 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 c6 5.f4 Be7 6.Bd3 0-0 7.Nf3 Na6 8.0-0 Nb4 9.Be2 c5 10.dxc5 dxc5 11.Bd2 Nc6 12.Bd3 Bd7 13.a3 b6 14.h3 Ne8 15.e5 f6 16.Qe2 fxe5 17.fxe5 Rd8 18.Ne4 Nc7 19.Nd6
37/44 11:13 2,284,901k 3,391k +11.92 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 c6 5.f4 Be7 6.Bd3 0-0 7.Nf3 Na6 8.0-0 Nb4 9.Be2 c5 10.dxc5 dxc5 11.Bd2 Nc6 12.Bd3 Bd7 13.a3 Rab8 14.g3 a6 15.Kg2 b5 16.b3 Bc8 17.e5 Nd5 18.Nxd5 exd5 19.c4 d4
38/49 14:16 3,066,598k 3,579k +11.90 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 c6 5.g4 d5 6.e5 Nfd7 7.f4 Be7 8.Nf3 a6 9.Qd2 c5 10.0-0-0 cxd4 11.Nxd4 Nc6 12.h4 Nxd4 13.Qxd4 Bc5 14.Qd2 Bxe3 15.Qxe3 h5 16.g5 0-0 17.Ne2 b6 18.Nd4 Bb7 19.Bg2 a5
39/48 20:26 4,589,964k 3,741k +11.93 1.e4 d6 2.d4 Nf6 3.Nc3 e6 4.Be3 c6 5.g4 d5 6.e5 Nfd7 7.f4 Be7 8.Nf3 g6 9.Kf2 h5 10.g5 0-0 11.b3 b6 12.Bg2 Bb7 13.Ne2 c5 14.c4 Na6 15.Re1 Kg7 16.a3 Nc7 17.Qc2 dxc4 18.bxc4 cxd4 19.Nfxd4 Bxg2 20.Kxg2
40/52 35:25 8,349,997k 3,929k +11.92 1.e4 d6 2.d4 a6 3.Be3 Nf6 4.f3 e5 5.d5 Nbd7 6.Nd2 Ng8 7.Ne2 Ne7 8.c4 f5 9.Nc1 b6 10.Nd3 f4 11.Bf2 g5 12.Be2 a5 13.h4 gxh4 14.Rxh4 Bg7 15.g3 Bf6 16.Rh5 fxg3 17.Bxg3 Bb7 18.Kf2 Kf7 19.Qh1 Kg7 20.Qh3 Rad8 21.Qg4+ Kf7
41/53 47:41 11,488,739k 4,015k +11.92 1.e4 d6 2.d4 a6 3.Be3 Nd7 4.f3 b6 5.Nd2 Bb7 6.c3 e6 7.Ne2 d5 8.Nf4 0-0-0 9.exd5 exd5 10.Qa4 a5 11.Kf2 c6 12.g4 Bd6 13.h4 Ne7 14.Bd3 g6 15.h5 g5 16.Ne2 h6 17.Qc2 c5 18.Bb5 Kc7 19.dxc5 Bxc5 20.Bxc5 Nxc5 21.Nd4 Ne6 22.Nf5
42/55 1:20:20 19,891,653k 4,127k +11.96 1.e4 d6 2.d4 a6 3.Be3 Nd7 4.f3 b6 5.g4 Bb7 6.c3 e6 7.Bg2 d5 8.Nd2 c6 9.Ne2 Bd6 10.Kf2 Ne7 11.h4 c5 12.e5 Bc7 13.h5 0-0 14.f4 f6 15.Bf3 Bc6 16.Qc2 c4 17.a4 g6 18.Kg2 Rf7 19.Rae1 Re8 20.b3 cxb3 21.Qxb3 Kg7
43/55 1:24:34 20,981,129k 4,135k +11.95 1.e4 d6 2.d4 e6 3.c4 a6 4.f4 Nd7 5.Nf3 b6 6.Nc3 g6 7.Bd3 Bb7 8.Qe2 Ne7 9.0-0 Bg7 10.Be3 0-0 11.Rad1 c6 12.g4 b5 13.e5 d5 14.c5 Rfd8 15.Kg2 a5 16.Qd2 h6 17.h3 h5 18.Ne2 hxg4 19.hxg4 a4 20.Rf2 f6 21.g5 fxe5 22.fxe5
44/55 1:28:27 21,940,334k 4,134k +11.94 1.e4 d6 2.d4 e6 3.c4 a6 4.f4 Nd7 5.Nf3 b6 6.Nc3 g6 7.Bd3 Bb7 8.Qe2 Ne7 9.0-0 Bg7 10.Be3 0-0 11.g4 h6 12.Rad1 f5 13.gxf5 gxf5 14.e5 dxe5 15.dxe5 Rf7 16.b4 Nc6 17.a3 Bf8 18.Rd2 Re7 19.Kf2 Bg7 20.Kg2 Rf7 21.Bf2 a5 22.b5 Ne7 23.a4

[zullil]

I get your point Louis but there is a difference between 'much worse' and 'lost'. It's clear that black is much worse here but is he lost? This is what Uri asked in the first post, I belive. There are many opening positions where engine gives +1.80 and later it occurs that it's not possible to convert this adventage into win.

[d]rnb1kbnr/ppp3pp/5p2/8/4q3/5N2/PPP2PPP/RNBQKB1R w KQkq - 0 7
SF-dev with default contempt:

+1.98 7. Be2 Bb4+ 8. c3 Bd6 9. O-O Ne7 10. Nbd2 Qg6 11. Re1 O-O 12. Nd4 Nbc6 13. Bh5 Qd3 14. Re3 Qa6 15. Be2 Qa5 16. b4 Qg5 17. Nxc6 Nxc6 18. Ne4 Qf5 19. Nxd6 cxd6 20. Qxd6 Ne5 21. f4 Nf7 22. Qc7 Qd7 23. Re7 Qxc7 24. Rxc7 Re8 25. Bh5 g6 26. Bf3 Nd6 27. c4 Be6 28. Bb2 Rac8 29. Rxc8 Bxc8 30. c5 Ne4 31. Rd1 f5 32. Be5 Kf7 33. a4 a5 34. bxa5 Nxc5 35. Rc1 Nd3 36. Rc7+ Ke6 37. Rxh7 Nxe5 38. fxe5 Rd8 39. Bxb7 Bxb7 40. Rxb7 Rd4 41. Rb6+ Kxe5 (depth 51, 2:22:03)

I'll let this go futher, but +1.98 seems pretty close to "won".

+2.08 7. Be2 Bd6 8. Nc3 Qe6 9. Nd4 Qd7 10. Ndb5 Be5 11. O-O Qxd1 12. Rxd1 Na6 13. f4 Bxc3 14. bxc3 f5 15. Re1 Nf6 16. Bc4+ Ne4 17. Bd5 Kd8 18. Ba3 Nac5 19. Rad1 Bd7 20. Nd4 Kc8 21. Bxc5 Nxc5 22. Re7 g6 23. Nb3 Nxb3 24. cxb3 a5 25. Bxb7+ Kxb7 26. Rdxd7 Rac8 27. Rxh7 Rxh7 28. Rxh7 Rd8 29. h4 Rd1+ 30. Kh2 Rf1 31. Kg3 a4 32. bxa4 Rc1 33. Rg7 Rxc3+ 34. Kf2 Rc6 35. g4 Rc2+ 36. Ke3 fxg4 37. Rxg6 Rxa2 38. h5 Rxa4 39. Rxg4 (depth 54, 5:39:05)

Seems we're getting there

Perhaps not.

+2.00 7. Be2 Bd6 8. Nc3 Qe6 9. Nd4 Qd7 10. Ndb5 Be5 11. O-O Qxd1 12. Rxd1 Na6 13. f4 Bxc3 14. bxc3 f5 15. Bc4 Nf6 16. Re1+ Ne4 17. Bd5 Kd8 18. Ba3 Bd7 19. Bxb7 Rb8 20. Bxa6 Rb6 21. Nxc7 Kxc7 22. Bd3 g6 23. Bb4 Kc8 24. a4 Re8 25. Red1 a6 26. Bf1 Rc6 27. Rd4 Be6 28. Ba5 Kb8 29. Rb1+ Ka7 30. Re1 Rb8 31. Bd3 Rcc8 32. h3 Rb7 33. Bxe4 fxe4 34. g4 Bd7 35. Rexe4 Bc6 36. Re6 Rb2 37. Rc4 Bd5 38. Re7+ Rb7 (depth 57, 10:14:38)

[EDIT]

Or maybe so ...

+2.09 7. Be2 Bd6 8. Nc3 Qe6 9. Nd4 Qd7 10. Ndb5 Be5 11. O-O Qxd1 12. Rxd1 Na6 13. f4 Bxc3 14. bxc3 f5 15. Bc4 Nf6 16. Re1+ Ne4 17. Bd5 Kd8 18. Ba3 Bd7 19. Bxb7 Rb8 20. Bxa6 Rb6 21. Nxc7 Kxc7 22. Bd3 g6 23. Bb4 Kc8 24. a4 Re8 25. Red1 a6 26. Bf1 Rc6 27. Rd4 Be6 28. Rad1 Kb7 29. Re1 Ra8 30. Ba5 Rb8 31. Bd3 Ka7 32. Bb4 Rb7 33. a5 Bd7 34. Bxe4 fxe4 35. Kf2 Rbc7 36. Ke3 Bf5 37. h3 h5 38. Rd5 Rc4 39. Rd8 Rc8 40. Rd6 R4c6 41. Rxc6 Rxc6 42. Rd1 (depth 58, 10:35:20)

[h1a8]

Can someone Monte Carlo it?
What's the statistics?

[zullil]

I get your point Louis but there is a difference between 'much worse' and 'lost'. It's clear that black is much worse here but is he lost? This is what Uri asked in the first post, I belive. There are many opening positions where engine gives +1.80 and later it occurs that it's not possible to convert this adventage into win.

[d]rnb1kbnr/ppp3pp/5p2/8/4q3/5N2/PPP2PPP/RNBQKB1R w KQkq - 0 7
SF-dev with default contempt:

+1.98 7. Be2 Bb4+ 8. c3 Bd6 9. O-O Ne7 10. Nbd2 Qg6 11. Re1 O-O 12. Nd4 Nbc6 13. Bh5 Qd3 14. Re3 Qa6 15. Be2 Qa5 16. b4 Qg5 17. Nxc6 Nxc6 18. Ne4 Qf5 19. Nxd6 cxd6 20. Qxd6 Ne5 21. f4 Nf7 22. Qc7 Qd7 23. Re7 Qxc7 24. Rxc7 Re8 25. Bh5 g6 26. Bf3 Nd6 27. c4 Be6 28. Bb2 Rac8 29. Rxc8 Bxc8 30. c5 Ne4 31. Rd1 f5 32. Be5 Kf7 33. a4 a5 34. bxa5 Nxc5 35. Rc1 Nd3 36. Rc7+ Ke6 37. Rxh7 Nxe5 38. fxe5 Rd8 39. Bxb7 Bxb7 40. Rxb7 Rd4 41. Rb6+ Kxe5 (depth 51, 2:22:03)

I'll let this go futher, but +1.98 seems pretty close to "won".

+2.08 7. Be2 Bd6 8. Nc3 Qe6 9. Nd4 Qd7 10. Ndb5 Be5 11. O-O Qxd1 12. Rxd1 Na6 13. f4 Bxc3 14. bxc3 f5 15. Re1 Nf6 16. Bc4+ Ne4 17. Bd5 Kd8 18. Ba3 Nac5 19. Rad1 Bd7 20. Nd4 Kc8 21. Bxc5 Nxc5 22. Re7 g6 23. Nb3 Nxb3 24. cxb3 a5 25. Bxb7+ Kxb7 26. Rdxd7 Rac8 27. Rxh7 Rxh7 28. Rxh7 Rd8 29. h4 Rd1+ 30. Kh2 Rf1 31. Kg3 a4 32. bxa4 Rc1 33. Rg7 Rxc3+ 34. Kf2 Rc6 35. g4 Rc2+ 36. Ke3 fxg4 37. Rxg6 Rxa2 38. h5 Rxa4 39. Rxg4 (depth 54, 5:39:05)

Seems we're getting there

Perhaps not.

+2.00 7. Be2 Bd6 8. Nc3 Qe6 9. Nd4 Qd7 10. Ndb5 Be5 11. O-O Qxd1 12. Rxd1 Na6 13. f4 Bxc3 14. bxc3 f5 15. Bc4 Nf6 16. Re1+ Ne4 17. Bd5 Kd8 18. Ba3 Bd7 19. Bxb7 Rb8 20. Bxa6 Rb6 21. Nxc7 Kxc7 22. Bd3 g6 23. Bb4 Kc8 24. a4 Re8 25. Red1 a6 26. Bf1 Rc6 27. Rd4 Be6 28. Ba5 Kb8 29. Rb1+ Ka7 30. Re1 Rb8 31. Bd3 Rcc8 32. h3 Rb7 33. Bxe4 fxe4 34. g4 Bd7 35. Rexe4 Bc6 36. Re6 Rb2 37. Rc4 Bd5 38. Re7+ Rb7 (depth 57, 10:14:38)

[EDIT]

Or maybe so ...

+2.09 7. Be2 Bd6 8. Nc3 Qe6 9. Nd4 Qd7 10. Ndb5 Be5 11. O-O Qxd1 12. Rxd1 Na6 13. f4 Bxc3 14. bxc3 f5 15. Bc4 Nf6 16. Re1+ Ne4 17. Bd5 Kd8 18. Ba3 Bd7 19. Bxb7 Rb8 20. Bxa6 Rb6 21. Nxc7 Kxc7 22. Bd3 g6 23. Bb4 Kc8 24. a4 Re8 25. Red1 a6 26. Bf1 Rc6 27. Rd4 Be6 28. Rad1 Kb7 29. Re1 Ra8 30. Ba5 Rb8 31. Bd3 Ka7 32. Bb4 Rb7 33. a5 Bd7 34. Bxe4 fxe4 35. Kf2 Rbc7 36. Ke3 Bf5 37. h3 h5 38. Rd5 Rc4 39. Rd8 Rc8 40. Rd6 R4c6 41. Rxc6 Rxc6 42. Rd1 (depth 58, 10:35:20)

Depth 60, after a day-long search:

+2.17 7. Be2 Nc6 8. Nc3 Qf5 9. O-O Bd6 10. Nb5 Nge7 11. Re1 Qd7 12. Bc4 a6 13. Nbd4 Nxd4 14. Nxd4 Qg4 15. Qd3 Be5 16. f4 b5 17. Bxb5+ axb5 18. fxe5 O-O 19. Re4 Qd7 20. exf6 Rxf6 21. Bg5 Rf7 22. Qxb5 Ng6 23. Re8+ Rf8 24. Rxf8+ Nxf8 25. Be3 Ne6 26. Qxd7 Bxd7 27. Nxe6 Bxe6 28. a4 Kf7 29. a5 Ra6 30. Bc5 Ke8 31. Re1 Kd8 32. b4 Ba2 33. Re7 Rg6 34. g3 h6 35. Re4 Ra6 36. c4 Bb1 37. Rd4+ Kc8 38. Kf2 Bg6 39. Ke3 Re6+ 40. Kd2 Re4 41. b5 Rxd4+ 42. Bxd4 Bf7 43. Kc3 g5 44. Kb4 Kb8 45. c5 Be6 46. c6 Kc8 47. Kc5 (depth 60, 23:31:53)

The position at the end of the PV is mate-in-10. Rather than searching deeper, some retrograde analysis seems in order, working backward from the mate-in-10 position.

[Karol Majewski]

Thanks, I think it's quite convincing now.

[Eelco de Groot]

Thanks, I think it's quite convincing now.

I think Louis was happy to do it, but you don't really need such big hardware I think, if you do it interactively. I was at 3.29 already on page one. I did not check going backwards but that could have been done in a few (more) hours. A little more if you have to go forward again several times. I only used one core/thread. Kaissa III may not be the best for this, but the interactive process will help compensate inaccuracies if there are some. And I only had 512 Mb, the more you have the better the results stay in memory. It's probably better even to use a Stockfish with permanent hash so you can keep the results if you wish, But I don't know if there is a practical use to being able to refute the Damiano with a gigantic hash table. Nobody would want to play the opening against you..