Gonzalez Freixas-Lecroq, corr Mate Postal-Jub25 A 2000

[Howard E]

Kg8
Qxb3 axb3
Bd8 Kf7
?

Am I missing something?

[Howard E]

Nice catch on Jon's original posting.

[Howard E]

Sorry, I mis-read your post. Ignore my last post.

[Eelco de Groot]

Nice catch on Jon's original posting.

Thanks Howard! Just as an update, I am trying out a specially made version just for the position, build 82 was probably not a good branch for other positions so I'm glad it isn't on the server yet

Build 114 finds 43... Qb3 but that may be more luck not skill, loses it again but the final score is satisfyingly high and is better than what you would get for 43... Qe7, I think. 44... Qd3+ seems good but if the engine picks 44... Qd1 instead surprisingly it is very hard to show a win so it is a bit of luck which variation is tried first, also because of some ridiculous extensions in the PV.

In the PV with 44... Qd1 I took one variation forward a few moves. Small hash, only 16 Mb, but even so the 16th ply running at 50% CPU took an awful long time. Because the score goes up so slowly here, it is no surprise from the original position the key move 43...Qb3 is lost with the first PVs following this variation.

43. Kb1 Qb3 44. Qb6 Qxb6 (44... Qd1+ {?!} 45. Ka2 Qd5+ 46. Kb1 Qh1+ * {See below, Black here seems to make only slow progress)
45. Bxb6 Bf6 0-1

[d]8/2B3bk/1Q4p1/7p/p4P1P/8/1P6/1K5q w - -

Engine: Rainbow Serpent 1.5 Build 114 (Athlon 2009 MHz, 16 MB)
by Romstad, Costalba, Kiiski, De Groot

1.00 0:00 -1.21 47.Kc2 (35) 1

2.00 0:00 -1.37 47.Kc2 Qxh4 48.Qb4 Qf2+ 49.Kd3 Bxb2
50.Qxa4 (1.245) 40

3.00 0:00 -1.37 47.Kc2 Qxh4 48.Qb4 Qf2+ 49.Kd3 Bxb2
50.Qxa4 (42.068) 300

4.00 0:02 -1.97 47.Kc2 Qxh4 48.b4 Qh2+ 49.Kd3 a3
50.Qb7 Qh3+ 51.Ke2 Qg4+ 52.Kd3 Qg3+
53.Ke2 Kh6 54.Qa8 (1.047.009) 378

4.02 0:02 -1.77 47.Ka2 Qxh4 48.Ka3 Qf6 49.Qb7 Qf7
50.Kxa4 Qa2+ 51.Kb5 Qxb2+ 52.Kc6 Qxb7+
53.Kxb7 (1.110.334) 378

5.01 0:08 -2.10 47.Ka2 Qxh4 48.Qe3 Qf6 49.Be5 Qe6+
50.Kb1 Bxe5 51.fxe5 h4 52.Kc1 h3
53.Kd2 h2 54.Qe4 Kg7 55.Ke2 (3.239.936) 400

6.01 0:10 -1.97 47.Ka2 Qxh4 48.Qe3 Qf6 49.Be5 Qe6+
50.Kb1 Bxe5 51.fxe5 h4 52.Kc1 h3
53.Kd2 h2 54.Qe4 Kg7 55.Ke2 (4.016.350) 390

7.01 0:14 -2.42 47.Ka2 Qxh4 48.Qc5 Qf6 49.Be5 Qe6+
50.Ka1 Bxe5 51.fxe5 g5 52.Qd6 Qf5
53.e6 g4 54.e7 Qf1+ 55.Ka2 Qc4+
56.Kb1 Qe4+ 57.Kc1 h4 (5.511.567) 392

8.01 0:24 -2.30 47.Ka2 Qxh4 48.Qc5 Qf6 49.Be5 Qe6+
50.Ka1 Bxe5 51.fxe5 g5 52.Qd6 Qf5
53.e6 g4 54.e7 Qf1+ 55.Ka2 Qc4+
56.Kb1 Qe4+ 57.Kc1 Kg7 (9.195.243) 378

9.01 0:27 -2.30 47.Ka2 Qxh4 48.Qc5 Qf6 49.Be5 Qe6+
50.Ka1 Bxe5 51.fxe5 g5 52.Qd6 Qf5
53.e6 g4 54.e7 Qf1+ 55.Ka2 Qc4+
56.Kb1 Qe4+ 57.Kc1 Kg7 (10.578.708) 378

10.01 0:33 -2.38 47.Ka2 Qxh4 48.Qc5 Qf6 49.Be5 Qe6+
50.Ka1 Qd7 51.Bxg7 Kxg7 52.Qc3+ Kh7
53.Qe1 Kg8 54.Qf2 Qd1+ 55.Ka2 Kf7
56.Qa7+ Kf6 57.Qf2 Qd5+ 58.Kb1 Kf5 (12.423.769) 376

11.01 1:21 -2.38 47.Ka2 Qxh4 48.Qc5 Qf6 49.Be5 Qe6+
50.Ka1 Qd7 51.Bxg7 Kxg7 52.Qc3+ Kh7
53.Qe1 Kg8 54.Qf2 Qd1+ 55.Ka2 Kf7
56.Qa7+ Kf6 57.Qf2 Qd5+ 58.Kb1 Kf5 (30.128.969) 370

12.01 2:53 -2.18++ 47.Ka2 (65.371.642) 377

13.01 17:36 -2.14 47.Ka2 Qxh4 48.Be5 Qe7 49.Qd4 h4
50.Qxa4 Bxe5 51.fxe5 Qe6+ 52.Ka3 g5
53.Qe4+ Kh6 54.Qd4 Kg7 55.Qe3 Qf5
56.b4 g4 57.Qa7+ Kg6 58.Qb6+ Kh5
59.e6 h3 60.e7 (425.190.260) 402

14.01 21:57 -2.22 47.Ka2 Qxh4 48.Be5 Qe7 49.Qd4 h4
50.Qxa4 Bxe5 51.fxe5 Qe6+ 52.Ka3 g5
53.Qe4+ Kh6 54.Qd4 Kg7 55.Qe3 Qf5
56.b4 g4 57.Qa7+ Qf7 58.Qd4 Qe6
59.b5 h3 60.Qf4 (526.852.809) 399

15.01 40:35 -2.54-- 47.Ka2 Qxh4 (962.731.413) 395

16.01 1165:52-2.66 47.Ka2 Qxh4 48.Qc5 Qh3 49.Be5 Qe6+
50.Ka1 Qd7 51.Bxg7 Kxg7 52.Qf2 Kf6
53.Qh4+ Kf7 54.Kb1 Qd1+ 55.Ka2 Qb3+
56.Ka1 Qc2 57.Ka2 Qe4 58.Qf2 Kf6
59.Qh4+ Kf5 60.Qg5+ (28.362.285.638) 405

best move: Kb1-a2 time: 1190:38.235 min n/s: 404.546 nodes: 28.899.630.207

But the position after 43. Kb1 went better once 44... Qd3+ was found:

[d]8/1QB2qbk/6p1/7p/p4P1P/8/1P6/1K6 b - -

Engine: Rainbow Serpent 1.5 Build 114 (Athlon 2009 MHz, 256 MB)
by Romstad, Costalba, Kiiski, De Groot

1.00 0:00 +0.44 43...Bd4 (73) 0

2.00 0:00 +0.44 43...Bd4 44.Qe4 (671) 1

2.00 0:00 +1.13 43...Bf6 44.Qc6 Bxh4 45.Be5 Be1
46.Qxa4 h4 (7.388) 18

3.00 0:00 +0.76 43...Bf6 44.Qc6 Qe7 45.Be5 Bxe5
46.fxe5 Qxh4 47.e6 Kh6 (28.897) 68

3.00 0:00 +1.13 43...Qe7 44.Kc2 Bf6 45.Kd2 Bxh4
46.Kd3 (50.170) 110

4.00 0:00 +1.17 43...Qe7 44.Ka2 Bf6 45.Qc6 Bxh4
46.Be5 Qb4 47.Kb1 Be7 (133.968) 231

5.00 0:00 +1.17 43...Qe7 44.Ka2 Bf6 45.Qc6 Bxh4
46.Be5 Qb4 47.Kb1 Be7 (295.752) 363

5.00 0:01 +1.25 43...Bf6 44.Qc6 Bxh4 45.Be5 Bf2
46.Qxa4 h4 47.Kc1 h3 48.Kd2 h2 (511.177) 454

6.01 0:01 +1.13 43...Bf6 44.Qc6 Bxh4 45.Be5 Bf2
46.Qa8 g5 47.Qe4+ Qg6 48.f5 Qf7
49.Kc2 (701.777) 510

6.02 0:02 +1.41 43...Qe7 44.Ka2 Kh6 45.Qc6 Qxh4
46.Qxa4 Qe1 47.Bd8 h4 48.Qd7 Kh7
49.Bg5 (1.245.789) 573

7.01 0:08 +1.45 43...Qe7 44.Kc2 Bf6 45.Qb8 Qe2+
46.Kb1 Qd1+ 47.Ka2 Qd5+ 48.Kb1 Qe4+
49.Kc1 Qe1+ 50.Kc2 Qf2+ 51.Kc1 Qxh4
52.Be5 Qe1+ 53.Kc2 Qe2+ 54.Kc3 Qe3+
55.Kc2 Qe4+ 56.Kd2 (5.736.362) 693

8.01 0:10 +1.45 43...Qe7 44.Kc2 Bf6 45.Qb8 Qe2+
46.Kb1 Qd1+ 47.Ka2 Qd5+ 48.Kb1 Qe4+
49.Kc1 Qe1+ 50.Kc2 Qf2+ 51.Kc1 Qxh4
52.Be5 Qe1+ 53.Kc2 Qe2+ 54.Kc3 Qe3+
55.Kc2 Qe4+ 56.Kd2 (7.932.297) 724

8.20 1:08 +1.69++ 43...Qb3 44.Qg2 a3 45.Be5 Bxe5
46.fxe5 Qxb2+ 47.Qxb2 axb2 48.Kxb2 g5
49.e6 Kg7 50.e7 Kf7 51.e8R Kxe8 (53.956.016) 786

9.01 1:21 +2.18 43...Qb3 44.Qb6 Qd1+ 45.Ka2 Qd5+
46.Kb1 Qh1+ 47.Ka2 Qxh4 48.Qc5 Qf6
49.Be5 Qf7+ 50.Kb1 h4 51.Kc1 Bxe5
52.fxe5 h3 53.Qd4 Qb3 (65.591.557) 802

10.01 1:26 +2.02 43...Qb3 44.Qb6 Qd1+ 45.Ka2 Qd5+
46.Kb1 Qh1+ 47.Ka2 Qxh4 48.Qc5 Qf6
49.Be5 Qf7+ 50.Kb1 h4 51.Kc1 Bxe5
52.fxe5 h3 53.Qd4 Kg7 54.Kd2 (69.770.840) 805

11.01 6:40 +2.02 43...Qb3 44.Qb6 Qd1+ 45.Ka2 Qd5+
46.Kb1 Qh1+ 47.Ka2 Qxh4 48.Qc5 Qf6
49.Be5 Qf7+ 50.Kb1 h4 51.Kc1 Bxe5
52.fxe5 h3 53.Qd4 Kg7 54.Kd2 h2 (317.929.139) 792

11.02 13:58 +2.14 43...Qe7 44.Kc2 Kh6 45.Qb8 Qe2+
46.Kc1 Qe1+ 47.Kc2 Qf2+ 48.Kd1 Qxh4
49.Be5 Qh1+ 50.Ke2 Qe4+ 51.Kf2 Bxe5
52.fxe5 Qd4+ 53.Kf3 Kg5 54.Qh8 Qd3+
55.Kf2 Kg4 56.Qb8 Qd2+ (658.126.171) 784

12.01 15:55 +1.97 43...Qe7 44.Qc6 Qxh4 45.Qxa4 Qg4
46.Qc6 Qe2 47.Qc2 Qf1+ 48.Ka2 h4
49.Be5 Bxe5 50.fxe5 h3 51.Qc8 g5
52.Qd7+ Kh6 53.Qd6+ Kh5 54.e6 Qb5
55.e7 g4 56.b4 Qe8 (757.069.193) 792

13.01 20:10 +2.22 43...Qe7 44.Qc6 Qxh4 45.Qxa4 Qg4
46.Qc6 Qe2 47.Qc2 Qf1+ 48.Qc1 Qg2
49.Be5 Bxe5 50.fxe5 Qe4+ 51.Ka2 Qd5+
52.b3 Qa5+ 53.Kb1 Qxe5 54.Qh1 Kg7
55.Kc2 Qe2+ 56.Kc3 g5 (958.965.094) 791

13.05 29:58 +2.42++ 43...Qb3 44.Qb6 Qd3+ 45.Ka2 Qc4+
46.Kb1 Bd4 47.Qb7 Qb3 48.Qg2 a3
49.Be5 Bxe5 50.fxe5 Kg7 51.Ka1 Qxb2+
52.Qxb2 axb2+ 53.Kxb2 g5 (1.228.534.497) 683

14.01 31:56 +3.27 43...Qb3 44.Qb6 Qd3+ 45.Ka2 Qc4+
46.Kb1 Bd4 47.Qb7 Qb3 48.Qxb3 axb3
49.Bd8 Kg7 50.Bg5 Bb6 51.Kc1 Be3+
52.Kb1 Bd4 53.Kc1 Kf7 54.Kb1 Ke6
55.Kc1 Kf5 56.Be7 Kxf4 (1.279.823.377) 667

15.01 45:01 +3.27 43...Qb3 44.Qb6 Qd3+ 45.Ka2 Qc4+
46.Kb1 Bd4 47.Qb7 Qb3 48.Qxb3 axb3
49.Bd8 Kg7 50.Bg5 Bb6 51.Kc1 Be3+
52.Kb1 Bd4 53.Kc1 Kf7 54.Kb1 Ke6
55.Kc1 Kf5 56.Be7 Kxf4 (1.585.822.780) 587

16.01 62:37 +3.35 43...Qb3 44.Qb6 Qd3+ 45.Ka2 Qc4+
46.Kb1 Bd4 47.Qb7 Qb3 48.Qxb3 axb3
49.Bd8 Kg7 50.Bg5 Bb6 51.Kc1 Be3+
52.Kb1 Bd4 53.Kc1 Kf7 54.Kd2 Bxb2
55.Kd3 Bd4 56.Kd2 Ke6 (2.020.101.300) 537

17.01 134:39 +3.15-- 43...Qb3 44.Qb6 (3.558.436.812) 440

18.01 227:08 +4.04++ 43...Qb3 (5.741.539.696) 421

19.01 458:36 +4.60 43...Qb3 44.Qb6 Qd3+ 45.Ka1 Qf1+
46.Ka2 Qc4+ 47.Kb1 Bd4 48.Qb8 Qb3
49.Qxb3 axb3 50.Kc1 Bf6 51.Bd6 Bxh4
52.Kd2 Bg3 53.Ke3 Kg7 54.Bc5 Kf7
55.Bd4 Be1 56.Ke4 Ke6 (11.606.367.411) 421

20.01 655:52 +4.68 43...Qb3 44.Qb6 Qd3+ 45.Ka1 Qf1+
46.Ka2 Qc4+ 47.Kb1 Bd4 48.Qb8 Qb3
49.Qxb3 axb3 50.Kc1 Bf6 51.Bb8 Bxh4
52.Kd2 Bg3 53.Ke3 Kg7 54.Ba7 Bh4
55.Kd3 Kf6 56.Kc4 Bg3 (16.180.095.931) 411

best move: Qf7-b3 time: 1315:57.969 min n/s: 416.160 nodes: 32.858.700.451

(The nodes per second goes down because by then there were two instances of the engine running.)

Eelco