The horizon effect

[gerold]

I will set this up again and see if R 2.2 fines it again.

[Don]

Hi Eelco

Terry claims that Rybka 3 can't see Qxc4 in this study of mine.
[d] 7k/2p1p2P/1p2p1P1/pp3Pp1/Q1qP4/6K1/6P1/8 w
Do you agree?

How does your version of Toga II and Stockfish do?

I will try to see if I can get Houdini to work on it.

Komodo 1.0 sees this one in about 20.3 minutes. Depth 25. I am trying komodo 1.2 now.

[gerold]

I will set this up again and see if R 2.2 fines it again.

R 2.2 w32 found it right off and moved within 5 sec. at depth 18.

[Don]

Hi Eelco

Terry claims that Rybka 3 can't see Qxc4 in this study of mine.
[d] 7k/2p1p2P/1p2p1P1/pp3Pp1/Q1qP4/6K1/6P1/8 w
Do you agree?

How does your version of Toga II and Stockfish do?

I will try to see if I can get Houdini to work on it.

Komodo 1.0 sees this one in about 20.3 minutes. Depth 25. I am trying komodo 1.2 now.

Komodo 1.2 does not see it, even after 35 ply and several hours.

[PawnStormZ]

   
        Houdini 1.03a finds the winning move in 14 seconds. Funny how some engines can not see certain solutions, yet play very strong chess!
       
[+10.60] d=30 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 Kd2 17.Qb2 Kd3 18.Qb3 Ke4 19.Qc2 Ke3 20.Qxc7 d4 21.Qxb6 a4 22.Qa5 d3 23.Qxg5 Kd4 24.Qa5 a3 25.Qxa3 d2 26.Qb4 Ke3 27.Qg4 Kf2 28.Qd1 Ke3 29.Qf3 Kd4 30.Qb3 Ke4 31.Qc2 Ke3 32.Qc3 Ke2 33.Qf3 Ke1 34.Qe3 Kd1 35.Qg5 Kc2 36.Qxd2 Kxd2 37.g4 Kc3 38.g5 Kc2 39.g6 Kd3 40.g7 Kc4 41.g8Q Kb4 42.Qa8 Kc5 (0:01:45) 948611kN

[+10.60] d=29 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 Kd2 17.Qb2 Kd3 18.Qb3 Ke4 19.Qc2 Ke3 20.Qxc7 g4 21.Qxb6 d4 22.Qxa5 d3 23.Qe1 Kd4 24.Qb4 Ke3 25.Qxg4 Kd2 26.Qf4 Ke2 27.Qe4 Kd2 28.Qb4 Ke2 29.Qc4 Ke3 30.Qe6 Kd4 31.Qg4 Kc3 32.Qd1 Kc4 33.Qa4 Kd5 34.Qa5 Kc4 35.Qa6 Kc3 36.Qc6 Kb2 37.Qa4 Kc1 38.Qc4 Kd2 39.Qa4 Ke2 40.Qe4 Kd2 (0:01:00) 523641kN

[+10.60] d=28 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 Kd2 17.Qb2 Kd3 18.Qb3 Ke4 19.Qc2 Ke3 20.Qxc7 g4 21.Qxb6 d4 22.Qxa5 d3 23.Qe1 Kd4 24.Qb4 Ke3 25.Qxg4 Kd2 26.Qf4 Ke2 27.Qf3 Kd2 28.Qe4 Kc3 29.Qc6 Kb2 30.Qa4 Kc1 31.Qc4 Kd2 32.Qa4 Ke2 33.Qe4 Kd2 34.Qd5 Kc2 35.Qc4 Kd2 36.Qa4 (0:00:44) 370364kN

[+10.40] d=28 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Kd4 16.Qxb1 Kc5 17.Qc2 Kb4 18.Qxc7 b5 19.Qd6 Kc4 20.Qc6 Kb4 21.Qxd5 g4 22.Qd2 Ka4 23.Qd7 g3 24.Kf6 Kb4 25.Qg4 Kb3 26.Qxg3 Ka4 27.Qf4 Kb3 28.Qe5 Kc4 29.Qc7 Kb4 30.Ke6 Ka4 31.Qc2 Kb4 32.Qd2 Ka4 33.Qd4 Kb3 34.Qd5 Ka3 35.Qxb5 (0:00:28) 221878kN

[+9.98] d=27 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Kd4 16.Qxb1 Kc5 17.Qc2 Kb4 18.Qxc7 b5 19.Qd6 Kc4 20.Qc6 Kb4 21.Qxd5 g4 22.Qd2 Ka4 23.Qd7 g3 24.Kf6 Kb4 25.Qg4 Kb3 26.Qxg3 Ka4 27.Qf4 Kb3 28.Qe5 Kc4 29.Qc7 Kb4 30.Ke6 Ka4 31.Qc2 Kb4 32.Qd2 Ka4 33.Qd4 Kb3 34.Qd5 Ka3 35.Qxb5 (0:00:27) 213857kN

[+9.86] d=27 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke5 16.Qxb1 d4 17.Qe1 Kd6 18.Qe6 Kc5 19.Qe5 Kc6 20.Qxd4 Kb5 21.Qd7 c6 22.Qd3 Kb4 23.Qb1 Kc5 24.Qc1 Kb5 25.g4 a4 26.Qxg5 c5 27.Qd5 Kb4 28.g5 a3 29.g6 c4 30.Qd6 Kb3 31.Qxb6 Kc2 32.g7 a2 33.Qg1 (0:00:25) 199816kN

[+9.14] d=27 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke5 16.Qxb1 d4 17.Qe1 Kd6 18.Qe6 Kc5 19.Qe5 Kc6 20.Qxd4 Kb5 21.Qd7 c6 22.Qd3 Kb4 23.Qb1 Kc5 24.Qc1 Kb5 25.g4 a4 26.Qxg5 c5 27.Qd5 Kb4 28.g5 a3 29.g6 c4 30.Qd6 Kb3 31.Qxb6 Kc2 32.g7 a2 33.Qg1 (0:00:25) 199752kN

[+8.78] d=26 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke5 16.Qxb1 d4 17.Qe1 Kd6 18.Qe6 Kc5 19.Qe5 Kc6 20.Qxd4 Kb5 21.Qd7 c6 22.Qd3 Kb4 23.Qb1 Kc5 24.Qc1 Kb5 25.g4 a4 26.Qxg5 c5 27.Qd5 Kb4 28.g5 a3 29.g6 c4 30.Qd6 Kb3 31.Qxb6 Kc2 32.g7 a2 33.Qg1 (0:00:25) 196140kN

[+10.37] d=25 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 a4 17.Qc1 Kd3 18.Qa3 Ke4 19.Qxa4 Kd3 20.Qb5 Kd4 21.Qc6 b5 22.Qxb5 g4 23.Qc6 Ke3 24.Qxc7 Kf2 25.Qc2 Kg3 26.Qb3 Kh4 27.g3 Kh3 28.Qxd5 (0:00:16) 117117kN

[+10.28] d=24 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 a4 17.Qc1 Kd3 18.Qa3 Ke4 19.Qxa4 Kd3 20.Qb5 Ke4 21.Qb1 Ke3 22.Qb3 Kd4 23.Qb4 Kd3 24.Qa3 Ke4 25.Qf3 Kd4 26.Qd1 Ke4 27.Qc2 Ke3 28.Qxc7 b5 29.Qc5 Ke4 30.Qxb5 Ke5 31.Qb7 Ke4 32.Qb6 Ke5 33.Qb2 Ke4 34.Qa3 Ke5 35.Qb2 Ke4 (0:00:15) 110492kN

[+10.28] d=23 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 a4 17.Qc1 Kd3 18.Qa3 Ke4 19.Qxa4 Kd3 20.Qb5 Ke4 21.Qb1 Kd4 22.Qb4 Kd3 23.Qb3 Kd4 24.Qb2 Ke4 25.Qe2 Kf4 26.Qf2 Ke4 27.Qc2 Ke3 28.Qxc7 b5 29.Qe5 Kf2 30.Qxg5 d4 31.Qxb5 Kg1 32.g4 (0:00:15) 108678kN

[+10.33] d=22 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 c3 5.Kf5 c2 6.Ke6 c1Q 7.Kf7 Qb1 8.g7 Kxh7 9.g8Q Kh6 10.Qg7 Kh5 11.Qh8 Kg4 12.Qh3 Kf4 13.Qf3 Ke5 14.Qxf6 Ke4 15.Qg6 Ke3 16.Qxb1 a4 17.Qc1 Kd3 18.Qa3 Ke4 19.Qxa4 Kf5 20.Qc2 Ke5 21.Qe2 Kf4 22.Qf1 Ke5 23.Qe1 Kf5 24.Qe6 Kf4 25.Qxd5 g4 26.Qd4 Kg3 27.Qd2 c6 28.Qc3 Kxg2 29.Qxc6 Kg3 30.Qxb6 (0:00:15) 105980kN

[+2.39] d=22 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 f5 5.Kxg5 Kg7 6.Kxf5 c5 7.Ke6 d4 8.h8Q Kxh8 9.Kf7 (0:00:14) 104481kN

[-0.01] d=22 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 f5 5.Kxg5 Kg7 6.Kxf5 c5 7.Ke6 d4 8.h8Q Kxh8 9.Kf7 (0:00:14) 104478kN

[-0.63] d=22 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 4.Kg4 f5 5.Kxg5 Kg7 6.Kxf5 c5 7.Ke6 d4 8.h8Q Kxh8 9.Kf7 (0:00:14) 104446kN

[-0.94] d=22 1.Qd1 Qc3 2.Kh2 Qe3 3.d5 Qe5 4.g3 exd5 5.Qc1 g4 6.Qg5 Qb2 7.Kh1 Qb1 8.Kg2 Qa2 9.Kf1 Qa1 10.Kg2 Qf6 11.Qf4 Qb2 12.Kg1 Qb1 13.Kh2 Qc2 14.Kg1 Qd1 15.Kh2 Qe2 16.Kg1 Qe1 17.Kh2 Qc3 18.Qxg4 b4 19.Kh3 Qf6 20.Kg2 b5 21.Qf4 Qc3 22.Qf1 Qc2 23.Kh1 Qe4 24.Kh2 Qc4 25.Qa1 Qc3 26.Qxa5 Qc2 27.Kg1 Qxf5 28.Qa8 (0:00:14) 104415kN

[-0.93] d=22 1.Qd1 Qc3 2.Kh2 Qe3 3.d5 Qe5 4.g3 exd5 5.Qc1 g4 6.Qh6 Qe2 7.Kg1 Qd1 8.Kh2 Qc2 9.Kg1 Qb1 10.Kh2 Qb2 11.Kg1 Qf6 12.Qf4 Qa1 13.Kh2 Qb2 14.Kg1 Qb1 15.Kh2 Qc2 16.Kg1 Qd1 17.Kh2 Qe2 18.Kg1 Qe1 19.Kh2 Qc3 20.Qh6 Qg7 21.Qf4 Qb2 22.Kg1 (0:00:13) 95031kN

[-1.07] d=22 1.Qd1 Qc3 2.Kh2 Qe3 3.d5 Qe5 4.g3 exd5 5.Qc1 g4 6.Qh6 Qe2 7.Kg1 Qd1 8.Kh2 Qc2 9.Kg1 Qb1 10.Kh2 Qb2 11.Kg1 Qf6 12.Qf4 Qa1 13.Kh2 Qb2 14.Kg1 Qb1 15.Kh2 Qc2 16.Kg1 Qd1 17.Kh2 Qe2 18.Kg1 Qe1 19.Kh2 Qc3 20.Qh6 Qg7 21.Qf4 Qb2 22.Kg1 (0:00:11) 77051kN

[-1.15] d=21 1.Qd1 Qc3 2.Kh2 Qe3 3.d5 Qe5 4.g3 exd5 5.Qc1 g4 6.Qh6 Qe2 7.Kg1 Qd1 8.Kh2 Qc2 9.Kg1 Qb1 10.Kh2 Qb2 11.Kg1 Qf6 12.Qf4 Qa1 13.Kh2 Qb2 14.Kg1 Qb1 15.Kh2 Qc2 16.Kg1 Qc3 17.Qxg4 a4 18.Kg2 a3 19.f6 Qd2 20.Kf1 Qd3 21.Kg1 Qe3 22.Kf1 (0:00:09) 60450kN

[-0.75] d=13 1.Qd1 Qc6 2.f6 exf6 3.Qh5 Qd6 4.Kh3 Qe7 5.Qf3 Qd8
6.Qc6 a4 7.Qxe6 a3 8.Qf7 (0:00:00) 2360kN   
   

[Eelco de Groot]

Hi Eelco

Terry claims that Rybka 3 can't see Qxc4 in this study of mine.
[d] 7k/2p1p2P/1p2p1P1/pp3Pp1/Q1qP4/6K1/6P1/8 w
Do you agree?

How does your version of Toga II and Stockfish do?

I will try to see if I can get Houdini to work on it.

Hi Jack!

I would have said it is probably very deep, but it seems from the post above that Houdini can find it quickly, 104 million nodes that would maybe be somewhere around three minutes on my machine. So that's not bad. Rainbow Serpent only sees it at very big depths, comparably to Rybka perhaps?

I can't check any of the newer Rybka's 3 or 4 but I do have the free Rybka 2.32a from the Peshk@ application by ChessOK installed. Maybe I'll try that later.

I first had to do something about that bug that caused Rainbow Serpent to see illusionist things in your other study, hope I have that provisionally fixed a bit now, in build 068. It is some trial and error what I'm doing at the moment, not too much appetite for all that real testing that would be necessary, and not on the old Athlon anyway, there it would not make much sense to run tournaments or do much long time control testing. Don't know how Houdini finds it fast here and if it is just that program that can do it.

Eelco

7k/2p1p2P/1p2p1P1/pp3Pp1/Q1qP4/6K1/6P1/8 w - -

Engine: Rainbow Serpent 1.8(s)dc Build 068 (Athlon 2009 MHz, 256 MB)
by Tord Romstad, Marco Costalba, Joona Kiiski

1.00 0:00 -3.35 1.Qa3 (670) 2

2.00 0:00 -3.35 1.Qa3 exf5 2.Qxe7 (727) 3

3.00 0:00 -4.16 1.Qa3 Qxd4 2.Kf3 Qf4+ 3.Ke2 exf5
4.Qxe7 (2.704) 11

4.00 0:00 -5.09 1.Qa3 Qxd4 2.g7+ Qxg7 3.fxe6 Kxh7 (5.784) 24

4.00 0:00 -4.98 1.Qa1 Qc1 (8.114) 32

4.00 0:00 -4.94 1.Qd1 Qe2 (9.390) 37

5.00 0:00 -4.56 1.Qd1 exf5 2.g7+ Kxg7 3.h8B+ Kxh8
4.Qh5+ Kg7 5.Qxg5+ Kf7 6.Qxf5+ Ke8 (12.698) 50

5.00 0:00 -4.29 1.Qa1 Qd3+ 2.Kg4 exf5+ 3.Kxg5 e5 (17.192) 64

6.00 0:00 -4.41 1.Qa1 Qd3+ 2.Kg4 exf5+ 3.Kxg5 Qa3 (23.919) 89

6.00 0:00 -4.08 1.Qd1 Qd5 2.fxe6 Qd6+ 3.Kf3 Qf4+
4.Ke2 Qg4+ 5.Ke1 Qxe6+ 6.Qe2 Qxe2+
7.Kxe2 (34.509) 116

7.00 0:00 -3.67 1.Qd1 Qc6 2.g7+ Kxg7 3.Qh5 Qd6+
4.Kh3 g4+ 5.Qxg4+ Kxh7 6.f6 (73.698) 214

8.00 0:00 -3.16 1.Qd1 b4 2.Qa4 Qd3+ 3.Kh2 b5 4.Qxa5 Qc4 (125.034) 296

9.00 0:00 -3.89-- 1.Qd1 c5 (206.319) 377

9.00 0:00 -3.44 1.Qd1 a4 2.Kg4 exf5+ 3.Kxg5 Qe6
4.Qh1 Qf6+ 5.Kh6 Qf7 (307.846) 437

10.00 0:01 -3.71 1.Qd1 Qc3+ 2.Kg4 Qe3 3.g3 exf5+
4.Kxf5 Qxg3 5.Qh5 Qf4+ 6.Ke6 Qf6+
7.Kd7 c5 (509.928) 509

11.01 0:01 -3.63 1.Qd1 Qc3+ 2.Kg4 Qe3 3.g3 exf5+
4.Kxf5 Qxg3 5.Qh5 Qf4+ 6.Ke6 Qf6+
7.Kd7 b4 8.Kxc7 Qd6+ 9.Kb7 (605.973) 531

12.01 0:01 -3.75 1.Qd1 Qc3+ 2.Kg4 Qe3 3.g3 exf5+
4.Kxf5 Qxg3 5.Qh5 (677.506) 548

13.01 0:01 -3.91-- 1.Qd1 Qc3+ (875.777) 577

13.01 0:02 -3.43++ 1.Qd1 Qc3+ (1.361.727) 613

13.01 0:02 -3.60 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf1 (1.439.977) 618

14.01 0:02 -3.77 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 (1.610.898) 628

15.01 0:03 -3.93 1.Qd1 Qc3+ 2.Kh2 (2.574.635) 653

16.01 0:05 -3.85 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf1 Qd6+ 5.g3 Qxg6 6.Qf8+ Kxh7
7.Qxe7+ Qg7 8.Qe4+ Kh6 9.Qc6+ Qg6
10.Qxb5 Qc2+ 11.Kg1 Qd1+ 12.Kg2 Qc1 (3.617.943) 669

17.01 0:07 -3.71 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf1 Qd6+ 5.g3 Qxg6 6.Qf8+ (5.251.445) 690

18.01 0:09 -3.88 1.Qd1 Qc3+ 2.Kh2 (6.925.028) 704

19.01 0:15 -3.95 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf1 Qd6+ 5.Kh1 Qf6 6.Qxb5 Qxg6
7.Kg1 Kxh7 8.Kf2 Qf6+ 9.Ke2 Qxd4
10.Qxg5 Qe4+ 11.Kd2 c6 12.g4 Qd4+
13.Ke2 e5 (10.794.386) 719

20.01 0:21 -3.79 1.Qd1 Qc3+ 2.Kh2 Qe3 (15.964.495) 730

21.01 0:40 -3.69 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf3 Qxg6 5.Qf8+ Kxh7 6.Qxe7+ Qg7
7.Qe4+ Kh6 8.Qc6+ Qg6 9.Qxc7 (29.910.163) 739

22.01 1:00 -3.79 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf3 Qxg6 5.Qf8+ Kxh7 6.Qxe7+ Kh8
7.Qe5+ Kg8 8.Qd5+ Kg7 9.Qxb5 (44.941.783) 743

23.01 1:39 -3.71 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf3 Qxg6 5.Qf8+ Kxh7 6.Qxe7+ Kh8
7.Qe5+ Kg8 8.Qd5+ Kg7 9.Qxb5 Qd6+
10.g3 Qxd4 (73.938.791) 741

24.01 2:15 -3.87-- 1.Qd1 Qc3+ (100.198.088) 742

24.01 21:12 -3.72 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf3 Qxg6 5.Qf8+ Kxh7 6.Qxe7+ Kh8
7.Qe5+ Kg8 8.Qxb5 Qd6+ 9.g3 (961.170.152) 755

25.01 24:05 -3.63 1.Qd1 Qc3+ 2.Kh2 Qe3 3.fxe6 Qxe6
4.Qf3 Qxg6 5.Qf8+ Kxh7 6.Qxe7+ Kh8
7.Qe5+ Kg8 8.Qxb5 Qd6+ 9.Kh3 Qxd4
10.Qxg5+ Kf7 (1.088.178.571) 752

26.01 34:15 -3.39++ 1.Qd1 Qc3+ (1.532.968.835) 745

26.01 37:45 -3.27++ 1.Qd1 b4 (1.685.067.640) 743

26.01 45:23 -3.03++ 1.Qd1 Qc6 (2.015.865.582) 740

26.01 53:22 -2.54++ 1.Qd1 a4 (2.364.778.796) 738

26.01 62:02 -1.57++ 1.Qd1 Qa2 (2.742.411.486) 736

26.01 83:47 0.00 {Pretty weird eval here?} 1.Qd1 Qa2 2.Qh5 Qa3+ 3.Kg4 exf5+
4.Kxf5 Qd3+ 5.Ke6 Qe4+ 6.Kf7 Qd5+
7.Kxe7 Qd6+ 8.Ke8 Qf6 9.Qh6 Qc6+
10.Kd8 Qd6+ 11.Ke8 Qe6+ (3.665.518.221) 729

27.01 94:39 -3.25 1.Qd1 Qc3+ 2.Kg4 Qe3 3.Qf3 Qxd4+
4.Kxg5 Qf6+ 5.Kh5 Kg7 6.g4 (4.134.175.781) 727

27.03 98:39 -0.04 1.Qxc4 bxc4 2.f6 exf6 (4.315.163.597) 728

28.01 99:05 +0.81 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5
4.Kg4 Kg7 (4.334.564.969) 729

29.01 100:20 +0.97 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (4.387.449.632) 728

30.01 101:49 +1.14 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (4.451.992.793) 728

31.01 106:35 +1.31 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (4.668.789.555) 729

32.01 114:53 +1.47 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (5.040.462.854) 731

33.01 141:56 +1.64 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (6.239.820.968) 732

34.01 162:14 +1.81 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (7.137.148.042) 733

35.01 170:14 +1.97 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (7.507.746.123) 734

36.01 184:39 +2.14 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (8.137.879.754) 734

37.01 199:58 +2.31 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (8.833.951.507) 736

38.01 264:12 +2.47 1.Qxc4 bxc4 2.f6 exf6 3.d5 exd5 (11.610.648.180) 732

best move: Qa4xc4 time: 471:02.609 min n/s: 640.906 nodes: 18.113.671.589

[Jack Lad]

If you like underpromotions then have a look at these two.
[d] 1b6/4P3/1P2PN2/8/2P5/P1k5/P1p2P2/K5B1 w - - 0 1
White to play and win by M. Liburkin.


[d] 5Q2/PP1B1P2/1P6/2B5/1p1P4/7p/nPR1bp1P/3k3K w - - 0 1
La Joconde
http://www.jmrw.com/Chess/Korokov/base.htm