On-line engine blitz tourney July

[bob]

I used a special book given to me by Peter a while back.

No idea what it would be. Haven't done a new book in 10 years now.

[Maarten Claessens]

This is an interesting position. They key is not finding axb3, but the maneuver Ra8 Qc7 and Qa5 afterwards, which is not that difficult. Gaviota prefers axb3 but insists on e2, which is pointless. SF sees the whole thing immediately. I will check this later, but sounds like a null move thing to me.

So, in this position (after axb3 axb3), the move is Ra8.
[D]3r3k/4q3/4pNpP/1b2P3/1p5Q/1P2p3/2P5/1KR5 b - - 0 46

Miguel

I guess it is all about king safety. Adjusting a king-attack parameter in WaDuuttie is enough to let is see the right move at ply 22 :

Code: Select all

FEN: 3r3k/4q3/4pNpP/1b2P3/1p5Q/1P2p3/2P5/1KR5 b - - 0 46 

WaDuuttie:
   1	00:00	          87	87	-1.48	e7c7
   2	00:00	         956	956	-1.72	e3e2 h4g4 e7f7 g4b4
   3	00:00	       1,954	1,954	-1.80	e3e2 h4g4 e7f7 c1h1
   4	00:00	       3,743	3,743	-1.78	e3e2 h4g4 e7f7 c1g1 d8a8

...

  20	00:14	  24,440,905	1,740,805	+0.40	e3e2 h4g4 e7a7 g4g6 d8a8 g6g7 a7g7 h6g7 h8g7 c1e1 a8a5 f6h5 g7f7 h5f4 b5a6 b1c1 a5e5 c1d2 f7f6 f4d3 a6d3 c2d3 e5c5 e1e2 c5c3 e2f2 f6e5
  21	00:17	  30,422,548	1,747,418	+0.52	e3e2!
  21	00:20	  36,674,407	1,764,040	+0.52	e3e2 h4g4 e7a7 g4g6 d8a8 g6g7 a7g7 h6g7 h8g7 c1e1 a8a5 f6h5 g7f7 h5f4 b5a6 b1c1 a5e5 c1d2 f7f6 f4d3 a6d3 c2d3 e5c5 e1e2 c5c3 e2e4 c3b3
  22	00:29	  49,826,630	1,696,514	+0.64	d8a8!
  22	00:47	  77,908,189	1,620,049	+1.64	d8a8!
  22	01:10	 111,647,455	1,579,171	+2.42	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e5e6 a8f8 f4f8 a7e3 c1b1 e3e1 b1b2 e1c3 b2b1 g6g5 e6e7 g5g4 e7e8q b5e8 f8e8 h7h6
  23	01:14	 118,881,094	1,588,045	+2.42	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e5e6 a8f8 f4f8 a7e3 c1b1 e3e1 b1b2 e1c3 b2b1 g6g5 e6e7 g5g4 e7e8q
  24	01:50	 173,732,612	1,576,234	+2.54	d8a8!
  24	03:00	 281,832,763	1,564,433	+3.28	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e5e6 d5d4 e3h3 b5f1 h3f3 f1e2 f4f7 a7f7 f3f7 h7h6
  25	03:04	 289,763,880	1,567,731	+2.80	d8a8?
  25	03:12	 302,714,073	1,569,361	+2.70	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e5e6 d5d4 e3h3 a7a1 c1d2 a8a7 f4g5 a1f1 h3h2 f1f5 g5f5 g6f5 h2h4
  26	04:39	 442,107,884	1,580,593	+3.10	d8a8!
  26	04:48	 458,173,330	1,584,990	+2.82	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e3g3 a7c7 c1b1 a8a7 f4f6 c7f7 f6f7 a7f7 g3g4 b5d7 g4b4 f7f1 b1b2 h7h6
  27	05:13	 498,892,478	1,588,677	+3.04	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e3g3 a7c7 c1b1 c7e7 f4d4 e7a7 d4a7 a8a7 g3g4 b5e2 g4b4 a7e7 b4a4 e7e5
  28	07:14	 697,108,221	1,603,838	+3.02	d8a8 h4d4 e7c7 c1e1 c7a5 e1e3 a8d8 d4g4 a5a7 f6d5 d8a8 b1c1 e6d5 g4f4 h8h7 e3g3 a7c7 c1b1 c7e7 e5e6 a8f8 f4d4 f8f1 b1b2 b5c6 g3h3 f1e1 b2a2 e7f8

I'm not sure though if this adjustment is an improvement in actual play!