a nice and difficult test position...

[MikeB]

A nice discovery by C Sullivan on the Rybka forum.

This is not a position from game 9, but it is derived from game # 9, AlphaZero vs. Stockfish. In that game, black (Stockfish) could have made whites win's much more difficult by playing 35. ... g5 36. hg5 Bc8 and then we have this position:

[d]2bk2r1/5q2/1p2pP1Q/pP1pP1P1/P2P4/8/2RK4/8 w - - 1 3

White here must avoid Rc6, which leads to a draw and play Kc1 which wins.

It takes a while, but SF-McBrain will evenrtually see this. One of oddest outputs you will ever see , after a string of failed highs with Rc6 and hitting 4.64 , it follows with a string of failed lows, dropping to 0.59 , then switching to Kc1 and steadily rises...

Code: Select all

	white viewpoint		fewer / Multi-PV setting = 1 / more
exclude: none best +tail                                          
dep	score	nodes	time	(not shown:  tbhits	knps	seldep)
 46	+3.91 	26.5G	18:15.19	Kc1 Bd7 Kb1 Rg6 Qh5 Ke8 Rh2 Kd8 Qf3 Be8 Rc2 Qf8 Qc3 Qb4+ Qxb4 axb4 Kb2 Rxg5 a5 Bxb5 axb6 Bc4 Rh2 Rg8 b7 Kc7 Rh7+ Kb8 Rg7 Rh8 f7 Rh2+ Kc1 Rf2 Rg8+ Kxb7 f8=Q Rxf8 Rxf8 Kc7 Kb2 b3 Rf7+ Kd8 Ra7 Ke8 Rb7 Kd8 Kc3 Ba6 Rb6 Bc8 Kxb3 Kd7  
 46	+3.72!	24.5G	16:54.94	Kc1! 
 46	+3.40!	22.9G	15:45.94	Kc1! 
 46	+3.07!	21.8G	15:02.65	Kc1! 
 46	+2.87?	21.7G	14:58.33	Kc1 Bd7? 
 45	+2.95 	20.8G	14:22.01	Kc1 Bd7 Kb1 Be8 Qh3 Qf8 Qc3 Qb4+ Qxb4 axb4 Kb2 Rxg5 a5 Bxb5 axb6 Bc4 Rh2 Rg8 b7 Kc7 Rh7+ Kb8 Rg7 Rh8 f7 Rh2+ Kc1 Rf2 Rg8+ Kxb7 f8=Q Rxf8 Rxf8 Kc7 Kb2 Kd7 Rf7+ Kd8 Kc1 Bb5 Rb7 Bc6 Ra7 Bb5 Kc2 Bc4 Rb7 b3+ Kb2 Ke8 Kc3 Kd8 Kb4 Kc8  
 45	+2.74!	20.0G	13:49.39	Kc1! 
 45	+2.50!	19.1G	13:08.80	Kc1! 
 45	+2.25!	17.8G	12:17.18	Kc1! 
 45	+2.00!	17.5G	12:00.81	Kc1! 
 45	+1.51!	17.2G	11:48.12	Kc1! 
 45	+1.31?	15.8G	10:51.39	Kc1 Bd7? 
 45	+1.47!	14.8G	10:12.30	Kc1! 
 45	+1.39?	14.7G	10:04.47	Kc1 Bd7? 
 45	+1.46?	14.3G	9:51.96	Kc1 Bd7? 
 45	+1.54?	14.2G	9:45.28	Kc1 Bd7? 
 45	+1.61?	13.8G	9:28.82	Kc1 Bd7? 
 45	+1.69?	12.9G	8:53.66	Kc1 Bd7? 
 45	+1.90!	12.8G	8:47.08	Kc1! 
 45	+1.76?	12.7G	8:41.35	Kc1 Bd7? 
 45	+1.84?	12.4G	8:31.90	Kc1 Bd7? 
 45	+2.01!	12.4G	8:28.70	Kc1! 
 45	+1.91?	12.2G	8:22.12	Kc1 Bd7? 
 45	+1.99?	12.2G	8:20.41	Kc1 Bd7? 
 45	+2.06?	12.1G	8:18.72	Kc1 Bd7? 
 44	+2.14 	12.0G	8:14.06	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Rb8+ Kf7 Rb7 Ke8 Ra7 Rxd4 Rxa5 Kf8 Ra8+ Be8 Kc2 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Kc5 Ke8 Ra7 Rc1+ Kd6 Rb1 Re7+ Kf8 Rb7 Rd1+ Kc5 R 
 43	+2.14 	11.8G	8:04.57	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Rb8+ Kf7 Rb7 Ke8 Ra7 Rxd4 Rxa5 Kf8 Ra8+ Be8 Kc2 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Kc5 Ke8 Ra7 Rc1+ Kd6 Rb1 Re7+ Kf8 Rb7 Rd1+ Kc5 R 
 43	+2.10!	11.7G	8:01.24	Kc1! 
 43	+1.90!	11.7G	8:00.14	Kc1! 
 43	+1.71!	11.6G	7:56.92	Kc1! 
 43	+1.57?	11.5G	7:54.13	Kc1 Bd7? 
 42	+1.65 	11.4G	7:47.75	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Rb8+ Kf7 Rb7 Ke8 Ra7 Rxd4 Rxa5 Kf8 Ra8+ Be8 Kc2 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 Re7 Ra1 Kb4 Rb1+ Ka5 d4 Rxe6 Re1 Rd6 d3 Rxd3 Rxe5 Rd4 Bh5 Kb6 Be2 Rb4 Kf7 a5 Kx 
 42	+1.39?	11.2G	7:40.11	Kc1 Bd7? 
 42	+1.46?	10.7G	7:18.70	Kc1 Bd7? 
 42	+1.54?	10.4G	7:07.90	Kc1 Bd7? 
 42	+1.61?	10.0G	6:51.27	Kc1 Bd7? 
 42	+1.69?	9.68G	6:36.16	Kc1 Bd7? 
 42	+1.76?	9.41G	6:24.97	Kc1 Bd7? 
 42	+1.84?	9.33G	6:21.47	Kc1 Bd7? 
 42	+1.91?	9.20G	6:16.31	Kc1 Bd7? 
 42	+2.10!	9.12G	6:12.89	Kc1! 
 42	+1.99?	9.10G	6:11.89	Kc1 Bd7? 
 42	+2.06?	9.07G	6:10.54	Kc1 Bd7? 
 41	+2.14 	9.03G	6:09.14	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Rb8+ Ke7 a7 Ra1 Rh8 Rb1 Rh7+ Kd8 Kc5 Rd1 Rh8+ Kd7 Rh3 Bg2 Rh7+ Kd8 Rh2 Bf3 
 40	+2.14 	8.96G	6:06.22	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Rb8+ Ke7 a7 Ra1 Rh8 Rb1 Rh7+ Kd8 Kc5 Rd1 Rh8+ Kd7 Kb6 Re1 Rh7+ Kd8 
 39	+2.14 	8.89G	6:03.26	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 Bh5 a6 Bf3 Rb8+ Ke7 a7 d4+ Kxd4 Ra1 Rh8 Kd7 Kc5 Rc1+ Kb6 Re1 Rf8 Bh1 Rf7+ Kd8 Rb7 Ra1  
 38	+2.14 	8.66G	5:53.32	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 Bh5 a6 Bf3 Rb8+ Ke7 a7 d4+ Kxd4 Ra1 Rh8 Kd7 Kc5 Rc1+ Kb6 Re1 Rf8 Bh1 Rf7+ Kd8 Rb7 Ra1  
 38	+1.98!	8.62G	5:51.73	Kc1! 
 38	+1.77!	8.61G	5:51.41	Kc1! 
 38	+1.37?	8.54G	5:48.53	Kc1 Bd7? 
 38	+1.95!	8.45G	5:44.72	Kc1! 
 38	+1.74!	8.25G	5:36.20	Kc1! 
 38	+1.45?	8.18G	5:33.28	Kc1 Bd7? 
 38	+1.52?	8.13G	5:31.13	Kc1 Bd7? 
 38	+1.60?	8.10G	5:30.08	Kc1 Bd7? 
 38	+1.67?	8.09G	5:29.55	Kc1 Bd7? 
 38	+1.75?	8.07G	5:28.90	Kc1 Bd7? 
 37	+1.82 	8.03G	5:26.95	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Kf8 Ra6 Rg4 Rxa5 Rxd4 Ra8+ Be8 Kc2 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Kc5 Ke8 Ra7 Rc1+ Kd6 Rb1 Re7+ Kf8 Rb7 Rd1+ Kc7 Ke8 Rb8+ Ke7 a7 Rc1+ Kb6 R 
 37	+1.66!	7.67G	5:12.50	Kc1! 
 37	+1.16!	7.13G	4:50.06	Kc1! 
 37	+0.67!	6.98G	4:43.67	Kc1! 
 37	+0.59?	6.56G	4:26.90	Rc6 Bd7? 
 37	+0.67?	6.36G	4:18.55	Rc6 Bd7? 
 37	+0.74?	6.25G	4:14.29	Rc6 Bd7? 
 37	+0.82?	6.08G	4:07.08	Rc6 Bd7? 
 37	+0.89?	5.90G	4:00.25	Rc6 Bd7? 
 37	+0.97?	5.81G	3:56.57	Rc6 Bd7? 
 37	+1.04?	5.75G	3:54.00	Rc6 Bd7? 
 37	+1.12?	5.68G	3:51.03	Rc6 Bd7? 
 37	+1.19?	5.60G	3:47.95	Rc6 Bd7? 
 37	+1.27?	5.48G	3:42.99	Rc6 Bd7? 
 37	+3.91!	5.28G	3:35.27	Rc6! 
 37	+3.41!	5.16G	3:30.34	Rc6! 
 37	+2.42!	5.09G	3:27.44	Rc6! 
 37	+1.92!	5.07G	3:26.84	Rc6! 
 37	+1.43!	5.05G	3:25.91	Rc6! 
 37	+1.34?	4.99G	3:23.38	Rc6 Bd7? 
 37	+1.42?	4.89G	3:19.43	Rc6 Bd7? 
 37	+1.49?	4.83G	3:16.89	Rc6 Bd7? 
 37	+1.57?	4.77G	3:14.78	Rc6 Bd7? 
 37	+1.64?	4.68G	3:11.14	Rc6 Bd7? 
 37	+1.72?	4.50G	3:03.70	Rc6 Bd7? 
 37	+1.79?	4.37G	2:58.43	Rc6 Bd7? 
 37	+1.87?	4.18G	2:50.60	Rc6 Bd7? 
 37	+1.94?	4.09G	2:46.76	Rc6 Bd7? 
 37	+2.02?	3.94G	2:40.72	Rc6 Bd7? 
 37	+2.09?	3.78G	2:34.00	Rc6 Bd7? 
 37	+2.17?	3.73G	2:32.08	Rc6 Bd7? 
 37	+2.24?	3.61G	2:27.26	Rc6 Bd7? 
 37	+2.32?	3.57G	2:25.55	Rc6 Bd7? 
 37	+2.39?	3.54G	2:24.33	Rc6 Bd7? 
 37	+2.47?	3.32G	2:15.62	Rc6 Bd7? 
 37	+2.54?	3.25G	2:12.66	Rc6 Bd7? 
 37	+2.62?	3.21G	2:11.05	Rc6 Bd7? 
 37	+2.69?	3.18G	2:09.89	Rc6 Bd7? 
 37	+2.77?	3.15G	2:08.63	Rc6 Bd7? 
 37	+2.84?	3.12G	2:07.52	Rc6 Bd7? 
 37	+2.92?	3.05G	2:04.51	Rc6 Bb7? 
 37	+2.99?	3.03G	2:03.68	Rc6 Bd7? 
 37	+3.07?	3.00G	2:02.79	Rc6 Bd7? 
 37	+3.14?	2.99G	2:02.06	Rc6 Bd7? 
 37	+3.22?	2.96G	2:00.96	Rc6 Bd7? 
 37	+3.29?	2.93G	1:59.99	Rc6 Bd7? 
 37	+3.37?	2.93G	1:59.79	Rc6 Bd7? 
 37	+3.44?	2.91G	1:59.02	Rc6 Bd7? 
 37	+3.52?	2.90G	1:58.61	Rc6 Bd7? 
 37	+3.59?	2.89G	1:58.35	Rc6 Bd7? 
 37	+3.67?	2.89G	1:58.20	Rc6 Bd7? 
 37	+3.74?	2.89G	1:58.03	Rc6 Bd7? 
 37	+3.82?	2.88G	1:57.86	Rc6 Bd7? 
 37	+3.89?	2.88G	1:57.70	Rc6 Bd7? 
 37	+3.97?	2.87G	1:57.40	Rc6 Bd7? 
 37	+4.61!	2.76G	1:52.76	Rc6! 
 37	+4.04?	2.65G	1:48.47	Rc6 Bd7? 
 37	+4.69!	2.29G	1:33.63	Rc6! 
 37	+4.12?	2.07G	1:24.75	Rc6 Bb7? 
 37	+4.19?	2.06G	1:24.31	Rc6 Bb7? 
 37	+4.27?	2.05G	1:24.16	Rc6 Bb7? 
 37	+4.34?	2.05G	1:23.86	Rc6 Bb7? 
 37	+4.42?	2.02G	1:22.73	Rc6 Bb7? 
 37	+4.49?	2.01G	1:22.56	Rc6 Bb7? 
 37	+4.57?	2.01G	1:22.48	Rc6 Bb7? 
 36	+4.64 	1.82G	1:14.83	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Rg2+ Kc3 Kd8 Ra6 Rg3+ Kd2 Kc7 Ra7+ Kb6 Re7 Bh5 Rd7 Rf3 Rxd5 Bg6 Rd7 Bd3 e6 Bg6 f7 Bxf7 Rd6+ Kc7 Rc6+ Kb7 exf7 Rf2+ Kd3 Rf3+ Kc4 R 
 35	+4.60 	1.62G	1:06.65	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Rg2+ Kc3 Kd8 Ra6 Rg3+ Kd2 Kc7 Ra7+ Kb6 Re7 Bh5 Rd7 Rf3 Rxd5 Bg6 Rd7 Bd3 e6 Bg6 Rd6+ Kc7 Rc6+ Kb8 f7 Bxf7 exf7 Rxf7 Ra6 Rf3 Rxa5 R 

 33	+4.27 	1.00G	0:41.33	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kb6 Rd7 Rf5 Rxd5 Rf2+ Kc3 Rf3+ Kd2 Bg6 Rd7 Bd3 e6 Bg6 Rd6+ Kc7 Rc6+ Kb7 f7 Bxf7 exf7 Rxf7 Ra6 Rf4 Kc3 Rf3+ Kc4 Rf7 Rxa5  
? 
 32	+3.81 	447.4M	0:18.60	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 b6 Ba6 g6 Rxg6 Qh8+ Kb7 Rd8 Kxb6 Ra8 Rg2+ Ke3 Qc7 Qb8+ Qxb8 Rxb8+ Ka7 f7 Kxb8 f8=Q+ Bc8 Qc5 Rb2 Qxa5 Kb7 Qc5 Rb6 Kf4 Rc6 Qb4+ Kc7 a5 Bd7 Qb5 Bc8 Kg5 Bb7 Qb4 Kb8 Kf4 Ka7 Qb5 Ka8 Kg5 Kb8 Qb4 Ka7 
 31	+3.81 	417.5M	0:17.39	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 b6 Ba6 g6 Rxg6 Qh8+ Kb7 Rd8 Kxb6 Ra8 Rg2+ Ke3 Qc7 Qb8+ Qxb8 Rxb8+ Ka7 f7 Kxb8 f8=Q+ Bc8 Qd6+ Kb7 Qe7+ Kb8 Qc5 Rb2 Qxa5 Kb7 Qc5 Rb6 Kf4 Rc6 Qb4+ Rb6 Qe7+ Ka6 Qc7 Bb7 Qc5 Rc6 Qb5+ Ka7 a5 
 31	+3.70?	406.2M	0:16.93	Rc6 Bb7? 
 30	+3.77!	383.2M	0:15.99	Rc6! 
 30	+3.39!	368.3M	0:15.36	Rc6! 
 30	+3.27?	355.6M	0:14.83	Rc6 Bd7? 
 30	+3.35?	352.0M	0:14.67	Rc6 Bd7? 
 30	+3.42?	350.8M	0:14.62	Rc6 Bb7? 
 29	+3.50 	328.8M	0:13.72	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kb6 Rd7 Rg2+ Kc3 Rg5 Rxd5 Rg3+ Kd2 Rf3 Rd7 Bg6 d5 Kc5 d6 Rd3+ Ke2 Kd4 Re7 Re3+ Kf2 Rxe5 d7 
 29	+3.34?	309.2M	0:12.92	Rc6 Bd7? 
 28	+3.42 	290.3M	0:12.15	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kd8 e6 Rg2+ Kc3 Rg3+ Kd2 Rg2+ Ke3 Rg6 Rd7+ Kc8 Rxd5 Rxf6 Rxh5 Rxe6+ Kf4 Kb7 d5 Re1 d6 Kb6 Rh8 
 28	+3.12!	270.5M	0:11.33	Rc6! 
 27	+2.81 	256.0M	0:10.72	Rc6 Bd7 Rxb6 Kc8 Qh3 Kc7 Rd6 Rc8 Qh6 Rg8 Kc1 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kd8 e6 Rg2+ Kc3 Rg3+ Kd2 Rg2+ Ke3 Rg6 Rd7+ Kc8 Rxd5 Rxf6 Rxh5 Rxe6+ Kf4 Kb7 d5 Re1 Kf5 Ra1 
 27	+3.31!	214.7M	0:09.02	Rc6! 
 27	+3.01!	196.9M	0:08.29	Rc6! 
 27	+2.70!	181.6M	0:07.66	Rc6! 
 27	+2.47?	180.1M	0:07.60	Rc6 Bd7? 
 27	+2.65?	179.0M	0:07.55	Rc6 Bd7? 
 26	+2.72 	158.8M	0:06.72	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Rc6+ Kb7 Kc1 Bd7 Rc2 Be8 Qh3 Qd7 Rc6 Rxg5 Qxe6 Rf5 Qxd7+ Bxd7 Rd6 Be8 Rxd5 Rf2 Rd6 Kc7 Ra6 Bg6 Rxa5 Kb7 Ra6 Rc2+ Kd1 Rc4 e6 Rxd4+ Kc1 Rc4+ Kd2 

 25	+1.98 	98.4M  	0:04.21	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Qh7 Qc8+ Qc2 Rxg5 Kb2 Rg8 Rb6+ Ka7 Ra6+ Kb8 Rxa5 Qf8 Qc5 Rg2+ Kc3 Qxc5+ dxc5 Rg3+ Kd2 Rg2+ Ke3 Rg5 c6 Bxc6 bxc6 Rxe5+ Kd4 Rf5 Kc5 Rxf6 Rb5+ Kc8 a5 Rf2 Kd6 e5 Kxd5 Ra2 Kd6 
 24	+1.98 	81.6M  	0:03.51	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Qh7 Qc8+ Qc2 Rxg5 Kb2 Qxc2+ Kxc2 Rg2+ Kd3 Kc8 Ra6 Rg3+ Kd2 Kb8 Rxa5 Be8 Ra6 Bf7 Rd6 Bg6 Rxe6 Rd3+ Ke2 Rxd4 a5 
 24	+1.95!	79.2M  	0:03.40	Rc6! 
 24	+1.76!	75.7M  	0:03.25	Rc6! 
 23	+1.57 	74.2M  	0:03.19	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Qh7 Qc8+ Kb2 Rxg5 Qc2 Rg1 Rb6+ Ka7 Ra6+ Kb8 Qxc8+ Bxc8 Rxa5 Rg2+ Kc3 Rg1 Kd2 Rg4 Ke3 Rg3+ Kf2 Rg8 Ke2 Rh8 Ke3 Rf8 Kf4 
 23	+1.75!	72.4M  	0:03.12	Rc6! 
 23	+1.55!	72.3M  	0:03.11	Rc6! 
 22	+1.65 	39.1M  	0:01.72	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Kd1 Bc8 Rc6 Bd7 Rc2 Qf7 Kc1 Be8 Qh3 Qd7 Rc6 Qd8 Rc5 Qd7 Qh4 Bg6 Kb2 Kb7 Qe1 Qd8 
 21	+2.53 	30.2M  	0:01.35	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Kd1 Ka8 Kd2 Qf7 Kc1 Bc8 Kb2 Kb7 Rc6 Bd7 Rc1 Be8 Qh3 Qd7 Qd3 Bg6 
 20	+2.40 	27.6M  	0:01.24	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Rc6+ Kb7 Rd6 Rf5 Rxd5 Rf2 e6 Rxf6 Rxh5 Rxe6 Kd2 Rd6 Ke3 Kb6 Ke4 Kc7 Rh8 
 19	+1.74 	13.5M  	0:00.64	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Qh2 Rxg5 Qc2 Rg1+ Kb2 Qc7 Qxc7+ Kxc7 Rxe6 Rg2+ Kc1 Bg6 Re7+ Kd8 e6 Rc2+ Kd1 Rc4 Rd7+ Ke8 Rxd5 Rxa4 
 18	+1.53 	8.31M  	0:00.40	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Kb2 Kb7 Ra6 Bd7 g6 Qxg6 Qxg6 Rxg6 Rxa5 Rg3 Ra6 Rf3 Kc2 Kb8 Kd2 Kc8 Ra7 Rf4 Kc3 
 17	+1.55 	6.07M  	0:00.29	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Kb2 Kb7 Qh3 Rxg5 Rxe6 Rh5 Qg4 Rh2+ Ka3 Rg2 Qxg2 Qxe6 Qd2 Qg4 Qc3 Qf5 
 16	+2.25 	3.87M  	0:00.18	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Kb2 Kb7 Qh4 Qh5 Qxh5 Bxh5 Rxe6 Rxg5 Rd6 Rg2+ Kc3 Rf2 Rxd5 Bg4 
 15	+2.03 	2.95M  	0:00.14	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb7 Kb2 Rg6 Qh2 Rxg5 Qc2 Rg1 Qc6+ Kb8 Qb6+ Qb7 Qxa5 Rg2+ Ka3 Rg3+ Kb4 Rd3 
 14	+2.27 	1.31M  	0:00.06	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Rc6+ Kb8 Ke3 Rg6 Qh5 Kb7 Qh4 Bd7 Ra6 Rg8 Rd6 
 13	+2.09 	500811	0:00.02	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Rc6+ Kb7 Ke1 Kb8 Rc1 Bb7 Kf2 Ka7 Rc2 Kb6 
 12	+1.87 	368536	0:00.02	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 g6 Rxg6 Qh8+ Rg8 Rd8+ Rxd8 Qxd8+ Bc8 Qb6+ Bb7 Qxa5 Qc7 Qxc7+ Kxc7 
 11	+1.32 	321160	0:00.02	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 g6 Rxg6 Qh8+ Bc8 Qd8 Rg2+ Ke3 Qh7 Rb6+ Ka7 Qe7+ Qxe7 fxe7 
 10	+1.89 	169101	0:00.01	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 b6 Kc8 Ke3 Kb8 g6 Rxg6 Qh8+ Rg8 Rd8+ Rxd8 Qxd8+ Bc8 Qe7 
  9	+0.64 	74341  	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 g6 Rxg6 Qh3 Rg1 Rxe6 Ka7 
  8	+2.15 	14902  	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Rd8 Rxd8 Kxd8 
  7	+2.15 	11220  	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Rd8 Rxd8 
  6	+2.16 	9724    	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 
  5	+2.17 	8291    	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 
  4	+2.60 	4774    	0:00.00	Rc6 Re8 Rxb6 Bb7 Rd6+ Kc7 
  3	+1.48 	2668    	0:00.00	Rc6 Bd7 Rxb6 
  2	+2.90 	1737    	0:00.00	Rc6 Bd7 Rxb6 
  1	+2.18 	627      	0:00.00	Rc6 

C, Sullivan's post:
www.rybkaforum.net/cgi-bin/rybkaforum/t ... pid=577955

[peter]

Hi Michael!

it is derived from game # 9, AlphaZero vs. Stockfish. In that game, black (Stockfish) could have made whites win's much more difficult by playing 35. ... g5 36. hg5 Bc8 and then we have this position:

[d]2bk2r1/5q2/1p2pP1Q/pP1pP1P1/P2P4/8/2RK4/8 w - - 1 3

White here must avoid Rc6, which leads to a draw and play Kc1 which wins.

Nice indeed!

[MikeGL]

A nice discovery by C Sullivan on the Rybka forum.

This is not a position from game 9, but it is derived from game # 9, AlphaZero vs. Stockfish. In that game, black (Stockfish) could have made whites win's much more difficult by playing 35. ... g5 36. hg5 Bc8 and then we have this position:

[d]2bk2r1/5q2/1p2pP1Q/pP1pP1P1/P2P4/8/2RK4/8 w - - 1 3

White here must avoid Rc6, which leads to a draw and play Kc1 which wins.

It takes a while, but SF-McBrain will evenrtually see this. One of oddest outputs you will ever see , after a string of failed highs with Rc6 and hitting 4.64 , it follows with a string of failed lows, dropping to 0.59 , then switching to Kc1 and steadily rises...

Code: Select all

	white viewpoint		fewer / Multi-PV setting = 1 / more
exclude: none best +tail                                          
dep	score	nodes	time	(not shown:  tbhits	knps	seldep)
 46	+3.91 	26.5G	18:15.19	Kc1 Bd7 Kb1 Rg6 Qh5 Ke8 Rh2 Kd8 Qf3 Be8 Rc2 Qf8 Qc3 Qb4+ Qxb4 axb4 Kb2 Rxg5 a5 Bxb5 axb6 Bc4 Rh2 Rg8 b7 Kc7 Rh7+ Kb8 Rg7 Rh8 f7 Rh2+ Kc1 Rf2 Rg8+ Kxb7 f8=Q Rxf8 Rxf8 Kc7 Kb2 b3 Rf7+ Kd8 Ra7 Ke8 Rb7 Kd8 Kc3 Ba6 Rb6 Bc8 Kxb3 Kd7  
 46	+3.72!	24.5G	16:54.94	Kc1! 
 46	+3.40!	22.9G	15:45.94	Kc1! 
 46	+3.07!	21.8G	15:02.65	Kc1! 
 46	+2.87?	21.7G	14:58.33	Kc1 Bd7? 
 45	+2.95 	20.8G	14:22.01	Kc1 Bd7 Kb1 Be8 Qh3 Qf8 Qc3 Qb4+ Qxb4 axb4 Kb2 Rxg5 a5 Bxb5 axb6 Bc4 Rh2 Rg8 b7 Kc7 Rh7+ Kb8 Rg7 Rh8 f7 Rh2+ Kc1 Rf2 Rg8+ Kxb7 f8=Q Rxf8 Rxf8 Kc7 Kb2 Kd7 Rf7+ Kd8 Kc1 Bb5 Rb7 Bc6 Ra7 Bb5 Kc2 Bc4 Rb7 b3+ Kb2 Ke8 Kc3 Kd8 Kb4 Kc8  
 45	+2.74!	20.0G	13:49.39	Kc1! 
 45	+2.50!	19.1G	13:08.80	Kc1! 
 45	+2.25!	17.8G	12:17.18	Kc1! 
 45	+2.00!	17.5G	12:00.81	Kc1! 
 45	+1.51!	17.2G	11:48.12	Kc1! 
 45	+1.31?	15.8G	10:51.39	Kc1 Bd7? 
 45	+1.47!	14.8G	10:12.30	Kc1! 
 45	+1.39?	14.7G	10:04.47	Kc1 Bd7? 
 45	+1.46?	14.3G	9:51.96	Kc1 Bd7? 
 45	+1.54?	14.2G	9:45.28	Kc1 Bd7? 
 45	+1.61?	13.8G	9:28.82	Kc1 Bd7? 
 45	+1.69?	12.9G	8:53.66	Kc1 Bd7? 
 45	+1.90!	12.8G	8:47.08	Kc1! 
 45	+1.76?	12.7G	8:41.35	Kc1 Bd7? 
 45	+1.84?	12.4G	8:31.90	Kc1 Bd7? 
 45	+2.01!	12.4G	8:28.70	Kc1! 
 45	+1.91?	12.2G	8:22.12	Kc1 Bd7? 
 45	+1.99?	12.2G	8:20.41	Kc1 Bd7? 
 45	+2.06?	12.1G	8:18.72	Kc1 Bd7? 
 44	+2.14 	12.0G	8:14.06	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Rb8+ Kf7 Rb7 Ke8 Ra7 Rxd4 Rxa5 Kf8 Ra8+ Be8 Kc2 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Kc5 Ke8 Ra7 Rc1+ Kd6 Rb1 Re7+ Kf8 Rb7 Rd1+ Kc5 R 
 43	+2.14 	11.8G	8:04.57	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Rb8+ Kf7 Rb7 Ke8 Ra7 Rxd4 Rxa5 Kf8 Ra8+ Be8 Kc2 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Kc5 Ke8 Ra7 Rc1+ Kd6 Rb1 Re7+ Kf8 Rb7 Rd1+ Kc5 R 
 43	+2.10!	11.7G	8:01.24	Kc1! 
 43	+1.90!	11.7G	8:00.14	Kc1! 
 43	+1.71!	11.6G	7:56.92	Kc1! 
 43	+1.57?	11.5G	7:54.13	Kc1 Bd7? 
 42	+1.65 	11.4G	7:47.75	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Rb8+ Kf7 Rb7 Ke8 Ra7 Rxd4 Rxa5 Kf8 Ra8+ Be8 Kc2 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 Re7 Ra1 Kb4 Rb1+ Ka5 d4 Rxe6 Re1 Rd6 d3 Rxd3 Rxe5 Rd4 Bh5 Kb6 Be2 Rb4 Kf7 a5 Kx 
 42	+1.39?	11.2G	7:40.11	Kc1 Bd7? 
 42	+1.46?	10.7G	7:18.70	Kc1 Bd7? 
 42	+1.54?	10.4G	7:07.90	Kc1 Bd7? 
 42	+1.61?	10.0G	6:51.27	Kc1 Bd7? 
 42	+1.69?	9.68G	6:36.16	Kc1 Bd7? 
 42	+1.76?	9.41G	6:24.97	Kc1 Bd7? 
 42	+1.84?	9.33G	6:21.47	Kc1 Bd7? 
 42	+1.91?	9.20G	6:16.31	Kc1 Bd7? 
 42	+2.10!	9.12G	6:12.89	Kc1! 
 42	+1.99?	9.10G	6:11.89	Kc1 Bd7? 
 42	+2.06?	9.07G	6:10.54	Kc1 Bd7? 
 41	+2.14 	9.03G	6:09.14	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Rb8+ Ke7 a7 Ra1 Rh8 Rb1 Rh7+ Kd8 Kc5 Rd1 Rh8+ Kd7 Rh3 Bg2 Rh7+ Kd8 Rh2 Bf3 
 40	+2.14 	8.96G	6:06.22	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Rb8+ Ke7 a7 Ra1 Rh8 Rb1 Rh7+ Kd8 Kc5 Rd1 Rh8+ Kd7 Kb6 Re1 Rh7+ Kd8 
 39	+2.14 	8.89G	6:03.26	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 Bh5 a6 Bf3 Rb8+ Ke7 a7 d4+ Kxd4 Ra1 Rh8 Kd7 Kc5 Rc1+ Kb6 Re1 Rf8 Bh1 Rf7+ Kd8 Rb7 Ra1  
 38	+2.14 	8.66G	5:53.32	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Rg4 Ra6 Kf8 Rxa5 Be8 Kc2 Rxd4 Ra8 Rb4 Kc3 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 Bh5 a6 Bf3 Rb8+ Ke7 a7 d4+ Kxd4 Ra1 Rh8 Kd7 Kc5 Rc1+ Kb6 Re1 Rf8 Bh1 Rf7+ Kd8 Rb7 Ra1  
 38	+1.98!	8.62G	5:51.73	Kc1! 
 38	+1.77!	8.61G	5:51.41	Kc1! 
 38	+1.37?	8.54G	5:48.53	Kc1 Bd7? 
 38	+1.95!	8.45G	5:44.72	Kc1! 
 38	+1.74!	8.25G	5:36.20	Kc1! 
 38	+1.45?	8.18G	5:33.28	Kc1 Bd7? 
 38	+1.52?	8.13G	5:31.13	Kc1 Bd7? 
 38	+1.60?	8.10G	5:30.08	Kc1 Bd7? 
 38	+1.67?	8.09G	5:29.55	Kc1 Bd7? 
 38	+1.75?	8.07G	5:28.90	Kc1 Bd7? 
 37	+1.82 	8.03G	5:26.95	Kc1 Bd7 Kb1 Ke8 Rc7 Qg6+ Qxg6+ Rxg6 Rb7 Rxg5 Rxb6 Kf8 Ra6 Rg4 Rxa5 Rxd4 Ra8+ Be8 Kc2 Rc4+ Kb3 Rc1 Rb8 Rb1+ Kc3 Kf7 Rb7+ Kf8 f7 Bxf7 a5 d4+ Kxd4 Bh5 a6 Bf3 Kc5 Ke8 Ra7 Rc1+ Kd6 Rb1 Re7+ Kf8 Rb7 Rd1+ Kc7 Ke8 Rb8+ Ke7 a7 Rc1+ Kb6 R 
 37	+1.66!	7.67G	5:12.50	Kc1! 
 37	+1.16!	7.13G	4:50.06	Kc1! 
 37	+0.67!	6.98G	4:43.67	Kc1! 
 37	+0.59?	6.56G	4:26.90	Rc6 Bd7? 
 37	+0.67?	6.36G	4:18.55	Rc6 Bd7? 
 37	+0.74?	6.25G	4:14.29	Rc6 Bd7? 
 37	+0.82?	6.08G	4:07.08	Rc6 Bd7? 
 37	+0.89?	5.90G	4:00.25	Rc6 Bd7? 
 37	+0.97?	5.81G	3:56.57	Rc6 Bd7? 
 37	+1.04?	5.75G	3:54.00	Rc6 Bd7? 
 37	+1.12?	5.68G	3:51.03	Rc6 Bd7? 
 37	+1.19?	5.60G	3:47.95	Rc6 Bd7? 
 37	+1.27?	5.48G	3:42.99	Rc6 Bd7? 
 37	+3.91!	5.28G	3:35.27	Rc6! 
 37	+3.41!	5.16G	3:30.34	Rc6! 
 37	+2.42!	5.09G	3:27.44	Rc6! 
 37	+1.92!	5.07G	3:26.84	Rc6! 
 37	+1.43!	5.05G	3:25.91	Rc6! 
 37	+1.34?	4.99G	3:23.38	Rc6 Bd7? 
 37	+1.42?	4.89G	3:19.43	Rc6 Bd7? 
 37	+1.49?	4.83G	3:16.89	Rc6 Bd7? 
 37	+1.57?	4.77G	3:14.78	Rc6 Bd7? 
 37	+1.64?	4.68G	3:11.14	Rc6 Bd7? 
 37	+1.72?	4.50G	3:03.70	Rc6 Bd7? 
 37	+1.79?	4.37G	2:58.43	Rc6 Bd7? 
 37	+1.87?	4.18G	2:50.60	Rc6 Bd7? 
 37	+1.94?	4.09G	2:46.76	Rc6 Bd7? 
 37	+2.02?	3.94G	2:40.72	Rc6 Bd7? 
 37	+2.09?	3.78G	2:34.00	Rc6 Bd7? 
 37	+2.17?	3.73G	2:32.08	Rc6 Bd7? 
 37	+2.24?	3.61G	2:27.26	Rc6 Bd7? 
 37	+2.32?	3.57G	2:25.55	Rc6 Bd7? 
 37	+2.39?	3.54G	2:24.33	Rc6 Bd7? 
 37	+2.47?	3.32G	2:15.62	Rc6 Bd7? 
 37	+2.54?	3.25G	2:12.66	Rc6 Bd7? 
 37	+2.62?	3.21G	2:11.05	Rc6 Bd7? 
 37	+2.69?	3.18G	2:09.89	Rc6 Bd7? 
 37	+2.77?	3.15G	2:08.63	Rc6 Bd7? 
 37	+2.84?	3.12G	2:07.52	Rc6 Bd7? 
 37	+2.92?	3.05G	2:04.51	Rc6 Bb7? 
 37	+2.99?	3.03G	2:03.68	Rc6 Bd7? 
 37	+3.07?	3.00G	2:02.79	Rc6 Bd7? 
 37	+3.14?	2.99G	2:02.06	Rc6 Bd7? 
 37	+3.22?	2.96G	2:00.96	Rc6 Bd7? 
 37	+3.29?	2.93G	1:59.99	Rc6 Bd7? 
 37	+3.37?	2.93G	1:59.79	Rc6 Bd7? 
 37	+3.44?	2.91G	1:59.02	Rc6 Bd7? 
 37	+3.52?	2.90G	1:58.61	Rc6 Bd7? 
 37	+3.59?	2.89G	1:58.35	Rc6 Bd7? 
 37	+3.67?	2.89G	1:58.20	Rc6 Bd7? 
 37	+3.74?	2.89G	1:58.03	Rc6 Bd7? 
 37	+3.82?	2.88G	1:57.86	Rc6 Bd7? 
 37	+3.89?	2.88G	1:57.70	Rc6 Bd7? 
 37	+3.97?	2.87G	1:57.40	Rc6 Bd7? 
 37	+4.61!	2.76G	1:52.76	Rc6! 
 37	+4.04?	2.65G	1:48.47	Rc6 Bd7? 
 37	+4.69!	2.29G	1:33.63	Rc6! 
 37	+4.12?	2.07G	1:24.75	Rc6 Bb7? 
 37	+4.19?	2.06G	1:24.31	Rc6 Bb7? 
 37	+4.27?	2.05G	1:24.16	Rc6 Bb7? 
 37	+4.34?	2.05G	1:23.86	Rc6 Bb7? 
 37	+4.42?	2.02G	1:22.73	Rc6 Bb7? 
 37	+4.49?	2.01G	1:22.56	Rc6 Bb7? 
 37	+4.57?	2.01G	1:22.48	Rc6 Bb7? 
 36	+4.64 	1.82G	1:14.83	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Rg2+ Kc3 Kd8 Ra6 Rg3+ Kd2 Kc7 Ra7+ Kb6 Re7 Bh5 Rd7 Rf3 Rxd5 Bg6 Rd7 Bd3 e6 Bg6 f7 Bxf7 Rd6+ Kc7 Rc6+ Kb7 exf7 Rf2+ Kd3 Rf3+ Kc4 R 
 35	+4.60 	1.62G	1:06.65	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Rg2+ Kc3 Kd8 Ra6 Rg3+ Kd2 Kc7 Ra7+ Kb6 Re7 Bh5 Rd7 Rf3 Rxd5 Bg6 Rd7 Bd3 e6 Bg6 Rd6+ Kc7 Rc6+ Kb8 f7 Bxf7 exf7 Rxf7 Ra6 Rf3 Rxa5 R 

 33	+4.27 	1.00G	0:41.33	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kb6 Rd7 Rf5 Rxd5 Rf2+ Kc3 Rf3+ Kd2 Bg6 Rd7 Bd3 e6 Bg6 Rd6+ Kc7 Rc6+ Kb7 f7 Bxf7 exf7 Rxf7 Ra6 Rf4 Kc3 Rf3+ Kc4 Rf7 Rxa5  
? 
 32	+3.81 	447.4M	0:18.60	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 b6 Ba6 g6 Rxg6 Qh8+ Kb7 Rd8 Kxb6 Ra8 Rg2+ Ke3 Qc7 Qb8+ Qxb8 Rxb8+ Ka7 f7 Kxb8 f8=Q+ Bc8 Qc5 Rb2 Qxa5 Kb7 Qc5 Rb6 Kf4 Rc6 Qb4+ Kc7 a5 Bd7 Qb5 Bc8 Kg5 Bb7 Qb4 Kb8 Kf4 Ka7 Qb5 Ka8 Kg5 Kb8 Qb4 Ka7 
 31	+3.81 	417.5M	0:17.39	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 b6 Ba6 g6 Rxg6 Qh8+ Kb7 Rd8 Kxb6 Ra8 Rg2+ Ke3 Qc7 Qb8+ Qxb8 Rxb8+ Ka7 f7 Kxb8 f8=Q+ Bc8 Qd6+ Kb7 Qe7+ Kb8 Qc5 Rb2 Qxa5 Kb7 Qc5 Rb6 Kf4 Rc6 Qb4+ Rb6 Qe7+ Ka6 Qc7 Bb7 Qc5 Rc6 Qb5+ Ka7 a5 
 31	+3.70?	406.2M	0:16.93	Rc6 Bb7? 
 30	+3.77!	383.2M	0:15.99	Rc6! 
 30	+3.39!	368.3M	0:15.36	Rc6! 
 30	+3.27?	355.6M	0:14.83	Rc6 Bd7? 
 30	+3.35?	352.0M	0:14.67	Rc6 Bd7? 
 30	+3.42?	350.8M	0:14.62	Rc6 Bb7? 
 29	+3.50 	328.8M	0:13.72	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kb6 Rd7 Rg2+ Kc3 Rg5 Rxd5 Rg3+ Kd2 Rf3 Rd7 Bg6 d5 Kc5 d6 Rd3+ Ke2 Kd4 Re7 Re3+ Kf2 Rxe5 d7 
 29	+3.34?	309.2M	0:12.92	Rc6 Bd7? 
 28	+3.42 	290.3M	0:12.15	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb8 Rc6 Bd7 Rb6+ Kc7 Rd6 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kd8 e6 Rg2+ Kc3 Rg3+ Kd2 Rg2+ Ke3 Rg6 Rd7+ Kc8 Rxd5 Rxf6 Rxh5 Rxe6+ Kf4 Kb7 d5 Re1 d6 Kb6 Rh8 
 28	+3.12!	270.5M	0:11.33	Rc6! 
 27	+2.81 	256.0M	0:10.72	Rc6 Bd7 Rxb6 Kc8 Qh3 Kc7 Rd6 Rc8 Qh6 Rg8 Kc1 Kb8 Kb2 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Re7+ Kd8 e6 Rg2+ Kc3 Rg3+ Kd2 Rg2+ Ke3 Rg6 Rd7+ Kc8 Rxd5 Rxf6 Rxh5 Rxe6+ Kf4 Kb7 d5 Re1 Kf5 Ra1 
 27	+3.31!	214.7M	0:09.02	Rc6! 
 27	+3.01!	196.9M	0:08.29	Rc6! 
 27	+2.70!	181.6M	0:07.66	Rc6! 
 27	+2.47?	180.1M	0:07.60	Rc6 Bd7? 
 27	+2.65?	179.0M	0:07.55	Rc6 Bd7? 
 26	+2.72 	158.8M	0:06.72	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Rc6+ Kb7 Kc1 Bd7 Rc2 Be8 Qh3 Qd7 Rc6 Rxg5 Qxe6 Rf5 Qxd7+ Bxd7 Rd6 Be8 Rxd5 Rf2 Rd6 Kc7 Ra6 Bg6 Rxa5 Kb7 Ra6 Rc2+ Kd1 Rc4 e6 Rxd4+ Kc1 Rc4+ Kd2 

 25	+1.98 	98.4M  	0:04.21	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Qh7 Qc8+ Qc2 Rxg5 Kb2 Rg8 Rb6+ Ka7 Ra6+ Kb8 Rxa5 Qf8 Qc5 Rg2+ Kc3 Qxc5+ dxc5 Rg3+ Kd2 Rg2+ Ke3 Rg5 c6 Bxc6 bxc6 Rxe5+ Kd4 Rf5 Kc5 Rxf6 Rb5+ Kc8 a5 Rf2 Kd6 e5 Kxd5 Ra2 Kd6 
 24	+1.98 	81.6M  	0:03.51	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Qh7 Qc8+ Qc2 Rxg5 Kb2 Qxc2+ Kxc2 Rg2+ Kd3 Kc8 Ra6 Rg3+ Kd2 Kb8 Rxa5 Be8 Ra6 Bf7 Rd6 Bg6 Rxe6 Rd3+ Ke2 Rxd4 a5 
 24	+1.95!	79.2M  	0:03.40	Rc6! 
 24	+1.76!	75.7M  	0:03.25	Rc6! 
 23	+1.57 	74.2M  	0:03.19	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Qh7 Qc8+ Kb2 Rxg5 Qc2 Rg1 Rb6+ Ka7 Ra6+ Kb8 Qxc8+ Bxc8 Rxa5 Rg2+ Kc3 Rg1 Kd2 Rg4 Ke3 Rg3+ Kf2 Rg8 Ke2 Rh8 Ke3 Rf8 Kf4 
 23	+1.75!	72.4M  	0:03.12	Rc6! 
 23	+1.55!	72.3M  	0:03.11	Rc6! 
 22	+1.65 	39.1M  	0:01.72	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Kd1 Bc8 Rc6 Bd7 Rc2 Qf7 Kc1 Be8 Qh3 Qd7 Rc6 Qd8 Rc5 Qd7 Qh4 Bg6 Kb2 Kb7 Qe1 Qd8 
 21	+2.53 	30.2M  	0:01.35	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Qe8 Kd1 Ka8 Kd2 Qf7 Kc1 Bc8 Kb2 Kb7 Rc6 Bd7 Rc1 Be8 Qh3 Qd7 Qd3 Bg6 
 20	+2.40 	27.6M  	0:01.24	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Qh2 Rxg5 Qc2 Qc7 Qxc7+ Kxc7 Rxe6 Bh5 Rc6+ Kb7 Rd6 Rf5 Rxd5 Rf2 e6 Rxf6 Rxh5 Rxe6 Kd2 Rd6 Ke3 Kb6 Ke4 Kc7 Rh8 
 19	+1.74 	13.5M  	0:00.64	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Qh2 Rxg5 Qc2 Rg1+ Kb2 Qc7 Qxc7+ Kxc7 Rxe6 Rg2+ Kc1 Bg6 Re7+ Kd8 e6 Rc2+ Kd1 Rc4 Rd7+ Ke8 Rxd5 Rxa4 
 18	+1.53 	8.31M  	0:00.40	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Kb2 Kb7 Ra6 Bd7 g6 Qxg6 Qxg6 Rxg6 Rxa5 Rg3 Ra6 Rf3 Kc2 Kb8 Kd2 Kc8 Ra7 Rf4 Kc3 
 17	+1.55 	6.07M  	0:00.29	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Kb2 Kb7 Qh3 Rxg5 Rxe6 Rh5 Qg4 Rh2+ Ka3 Rg2 Qxg2 Qxe6 Qd2 Qg4 Qc3 Qf5 
 16	+2.25 	3.87M  	0:00.18	Rc6 Bd7 Rxb6 Kc7 Rd6 Kb8 Kc1 Be8 Kb2 Kb7 Qh4 Qh5 Qxh5 Bxh5 Rxe6 Rxg5 Rd6 Rg2+ Kc3 Rf2 Rxd5 Bg4 
 15	+2.03 	2.95M  	0:00.14	Rc6 Bd7 Rxb6 Kc7 Rd6 Bc8 Kc1 Kb7 Kb2 Rg6 Qh2 Rxg5 Qc2 Rg1 Qc6+ Kb8 Qb6+ Qb7 Qxa5 Rg2+ Ka3 Rg3+ Kb4 Rd3 
 14	+2.27 	1.31M  	0:00.06	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Rc6+ Kb8 Ke3 Rg6 Qh5 Kb7 Qh4 Bd7 Ra6 Rg8 Rd6 
 13	+2.09 	500811	0:00.02	Rc6 Bb7 Rxb6 Kc7 Rd6 Bc8 Rc6+ Kb7 Ke1 Kb8 Rc1 Bb7 Kf2 Ka7 Rc2 Kb6 
 12	+1.87 	368536	0:00.02	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 g6 Rxg6 Qh8+ Rg8 Rd8+ Rxd8 Qxd8+ Bc8 Qb6+ Bb7 Qxa5 Qc7 Qxc7+ Kxc7 
 11	+1.32 	321160	0:00.02	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 g6 Rxg6 Qh8+ Bc8 Qd8 Rg2+ Ke3 Qh7 Rb6+ Ka7 Qe7+ Qxe7 fxe7 
 10	+1.89 	169101	0:00.01	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 b6 Kc8 Ke3 Kb8 g6 Rxg6 Qh8+ Rg8 Rd8+ Rxd8 Qxd8+ Bc8 Qe7 
  9	+0.64 	74341  	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 g6 Rxg6 Qh3 Rg1 Rxe6 Ka7 
  8	+2.15 	14902  	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Rd8 Rxd8 Kxd8 
  7	+2.15 	11220  	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Rd8 Rxd8 
  6	+2.16 	9724    	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 Kb8 
  5	+2.17 	8291    	0:00.00	Rc6 Bb7 Rxb6 Kc7 Rd6 
  4	+2.60 	4774    	0:00.00	Rc6 Re8 Rxb6 Bb7 Rd6+ Kc7 
  3	+1.48 	2668    	0:00.00	Rc6 Bd7 Rxb6 
  2	+2.90 	1737    	0:00.00	Rc6 Bd7 Rxb6 
  1	+2.18 	627      	0:00.00	Rc6 

C, Sullivan's post:
www.rybkaforum.net/cgi-bin/rybkaforum/t ... pid=577955

Wow, 35...g5! is an amazing resource. I wonder if it can be spotted easily by SF9. Not sure what to call that type of pawn sacrifice, not a gambit nor a vacating sacrifice. Maybe a deep engine move to remove an outside passer (h-pawn).

[peter]

Hi Mike!

C, Sullivan's post:
www.rybkaforum.net/cgi-bin/rybkaforum/t ... pid=577955

Wow, 35...g5! is an amazing resource. I wonder if it can be spotted easily by SF9. Not sure what to call that type of pawn sacrifice, not a gambit nor a vacating sacrifice. Maybe a deep engine move to remove an outside passer (h-pawn).

Yet a trap only, as CSullivan writes in his post, after 37.Kc1(!)
it loses completely too.
But the easy to be made blunder 37.Rc6(?)
would indeed cost the half point, so the given position is a good one for testing.

[zullil]

A nice discovery by C Sullivan on the Rybka forum.

This is not a position from game 9, but it is derived from game # 9, AlphaZero vs. Stockfish. In that game, black (Stockfish) could have made whites win's much more difficult by playing 35. ... g5 36. hg5 Bc8 and then we have this position:

[d]2bk2r1/5q2/1p2pP1Q/pP1pP1P1/P2P4/8/2RK4/8 w - - 1 3

White here must avoid Rc6, which leads to a draw and play Kc1 which wins.

It takes a while, but SF-McBrain will evenrtually see this. One of oddest outputs you will ever see , after a string of failed highs with Rc6 and hitting 4.64 , it follows with a string of failed lows, dropping to 0.59 , then switching to Kc1 and steadily rises...

C, Sullivan's post:
www.rybkaforum.net/cgi-bin/rybkaforum/t ... pid=577955

Latest Cfish also found Kc1 at depth 37:

Code: Select all

info depth 37 seldepth 66 multipv 1 score cp 81 nodes 6457194275 nps 48075004 hashfull 740 tbhits 0 time 134315 pv d2c1 c8d7 c1b1 d8e8 c2c7 f7g6 h6g6 g8g6 f6f7 e8f8 c7d7 g6g5 b1c2 g5g2 c2d3 g2g3 d3d2 g3a3 d7b7 a3a4 d2e3 a4a2 e3f4 a2g2 b7b6 f8f7 b6b7 f7g6 b7e7 g2f2 f4e3 f2b2 e7e6 g6f5 e6f6 f5g5 f6b6 b2b3 e3d2 a5a4 b6b8 g5g6 b8a8 b3b5 a8a4 g6f5 d2c3 b5b6 a4b4 b6c6 c3d3 c6a6

You missed out on another down-and-up:

Code: Select all

info depth 54 seldepth 25 multipv 1 score cp 0 nodes 61139252342 nps 48738555 hashfull 999 tbhits 0 time 1254433 pv d2c1 c8d7 c1b2 g8g6 h6h3 f7f8 b2a2 f8b4 h3h8 d7e8 c2c8 d8c8 h8e8 c8c7 e8g6 b4a4 a2b1 a4d1 b1b2 d1d4 b2b3 d4c4 b3b2 c4d4
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 36 multipv 1 score cp 7 lowerbound nodes 75232324884 nps 48762486 hashfull 999 tbhits 0 time 1542832 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 42 multipv 1 score cp 15 lowerbound nodes 76042554007 nps 48760480 hashfull 999 tbhits 0 time 1559512 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 75 multipv 1 score cp 26 lowerbound nodes 76332123121 nps 48759689 hashfull 999 tbhits 0 time 1565476 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 75 multipv 1 score cp 42 lowerbound nodes 76415935591 nps 48759281 hashfull 999 tbhits 0 time 1567208 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 75 multipv 1 score cp 63 lowerbound nodes 76721076650 nps 48758540 hashfull 999 tbhits 0 time 1573490 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 88 multipv 1 score cp 92 lowerbound nodes 82378459234 nps 48741074 hashfull 999 tbhits 0 time 1690124 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 88 multipv 1 score cp 131 lowerbound nodes 86176952910 nps 48759305 hashfull 999 tbhits 0 time 1767395 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 88 multipv 1 score cp 181 lowerbound nodes 86839564245 nps 48759591 hashfull 999 tbhits 0 time 1780974 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 88 multipv 1 score cp 245 lowerbound nodes 88411609951 nps 48747513 hashfull 999 tbhits 0 time 1813664 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 88 multipv 1 score cp 328 lowerbound nodes 95298320626 nps 48704663 hashfull 999 tbhits 0 time 1956657 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 99 multipv 1 score cp 433 lowerbound nodes 110960782888 nps 48702404 hashfull 999 tbhits 0 time 2278343 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 121 multipv 1 score cp 566 lowerbound nodes 175077602133 nps 49012363 hashfull 999 tbhits 0 time 3572111 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 seldepth 121 multipv 1 score cp 735 lowerbound nodes 211139136028 nps 49318437 hashfull 999 tbhits 0 time 4281140 pv d2c1
info depth 55 currmove d2c1 currmovenumber 1
info depth 55 currmove c2c6 currmovenumber 2
info depth 55 currmove c2b2 currmovenumber 3
info depth 55 currmove h6f8 currmovenumber 4
info depth 55 currmove c2c7 currmovenumber 5
info depth 55 currmove d2e3 currmovenumber 6
info depth 55 currmove g5g6 currmovenumber 7
info depth 55 currmove c2c1 currmovenumber 8
info depth 55 currmove d2e1 currmovenumber 9
info depth 55 currmove h6h4 currmovenumber 10
info depth 55 currmove d2d1 currmovenumber 11
info depth 55 currmove d2c3 currmovenumber 12
info depth 55 currmove c2c3 currmovenumber 13
info depth 55 currmove d2e2 currmovenumber 14
info depth 55 currmove h6g6 currmovenumber 15
info depth 55 currmove h6h7 currmovenumber 16
info depth 55 currmove h6h3 currmovenumber 17
info depth 55 currmove h6h8 currmovenumber 18
info depth 55 currmove d2d3 currmovenumber 19
info depth 55 currmove h6g7 currmovenumber 20
info depth 55 currmove c2a2 currmovenumber 21
info depth 55 currmove h6h5 currmovenumber 22
info depth 55 currmove h6h2 currmovenumber 23
info depth 55 currmove c2c5 currmovenumber 24
info depth 55 currmove h6h1 currmovenumber 25
info depth 55 currmove c2c4 currmovenumber 26
info depth 55 currmove c2c8 currmovenumber 27
info depth 55 seldepth 121 multipv 1 score cp 752 nodes 268101714696 nps 49929392 hashfull 999 tbhits 0 time 5369617 pv d2c1 c8d7 c1b1 d7e8 h6h3 f7f8 h3c3 f8b4 c3b4 a5b4 b1b2 g8h8 g5g6 e8g6 c2c6 h8h2 b2b3 h2h1 c6b6 h1b1 b3a2 b1f1 b6d6 d8c7 d6c6 c7d7 a4a5 g6d3 a2b3 d3b5 c6d6 d7c7 d6e6 f1b1 b3c2 b1f1 a5a6 b5a4 c2d2 f1d1 d2e3 d1e1 e3f2 e1h1 f6f7 h1h8 e6e7 c7b6 a6a7 h8f8 f2e3 f8a8 e5e6 b4b3 e7e8 a4e8 f7f8q e8c6 f8c5 b6c7 c5e7 c7b6 e3f4 a8a7 e7b4 b6c7 b4b3 a7a1 f4e5 a1e1 e5f6 e1f1 f6e7 f1g1 b3c3 g1b1 c3g3 c7b7 e7d6 c6a4 g3g7 b7a6 g7f8 a6a5 f8a8 a5b4 a8b8 a4b5 e6e7 b4c4 e7e8q b5e8 b8b1 c4d4 b1b4 d4d3 d6d5

[Ron Langeveld]

.. after a string of failed highs with Rc6 and hitting 4.64 , it follows with a string of failed lows, dropping to 0.59 , then switching to Kc1 and steadily rises...

a string of fail lows, yet not a single string with a PV that shows why it drops to 0.59

Would be nice if the output actually shows the reason why the score drops

Ron

[zullil]

.. after a string of failed highs with Rc6 and hitting 4.64 , it follows with a string of failed lows, dropping to 0.59 , then switching to Kc1 and steadily rises...

a string of fail lows, yet not a single string with a PV that shows why it drops to 0.59

Would be nice if the output actually shows the reason why the score drops

Ron

Code: Select all

position fen 2bk2r1/5q2/1p2pP1Q/pP1pP1P1/P2P4/8/2RK4/8 w - - 1 3
d

 +---+---+---+---+---+---+---+---+
 |   |   | b | k |   |   | r |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   | q |   |   |
 +---+---+---+---+---+---+---+---+
 |   | p |   |   | p | P |   | Q |
 +---+---+---+---+---+---+---+---+
 | p | P |   | p | P |   | P |   |
 +---+---+---+---+---+---+---+---+
 | P |   |   | P |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   | R | K |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+

Fen: 2bk2r1/5q2/1p2pP1Q/pP1pP1P1/P2P4/8/2RK4/8 w - - 1 3
Key: 947681C2B814E86B
Checkers: 
go infinite searchmoves c2c6

Code: Select all

info depth 41 seldepth 70 multipv 1 score cp 443 nodes 5332086349 nps 34440330 hashfull 907 tbhits 0 time 154821 pv c2c6 c8d7 c6b6 d8c7 b6d6 d7c8 d2c1 c7b8 d6c6 c8d7 c6b6 b8a7 b6d6 a7b8 c1b2 d7e8 h6h2 g8g5 h2c2 f7c7 c2c7 b8c7 d6e6 g5g8 b2c3 g8h8 e6e7 c7b6 c3d2 e8g6 e7d7 h8h4 d7d5 h4e4 d5d6 b6c7 d6c6 c7b7 d2c3 g6f7 c6d6 f7a2 d6a6 e4e3 c3d2 e3f3 d2e2 f3a3 e5e6 a2c4 e2f2 a3a4 f6f7 c4b5 f7f8q b7a6 f8d6 a6b7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 436 upperbound nodes 5859488000 nps 34412516 hashfull 924 tbhits 0 time 170272 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 428 upperbound nodes 5918522731 nps 34411016 hashfull 928 tbhits 0 time 171995 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 417 upperbound nodes 5966744388 nps 34407512 hashfull 929 tbhits 0 time 173414 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 401 upperbound nodes 6013844845 nps 34406902 hashfull 931 tbhits 0 time 174786 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 380 upperbound nodes 6146434444 nps 34358160 hashfull 936 tbhits 0 time 178893 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 350 upperbound nodes 6257947344 nps 34292753 hashfull 942 tbhits 0 time 182486 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 312 upperbound nodes 6405548882 nps 34212741 hashfull 949 tbhits 0 time 187227 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 262 upperbound nodes 6605885599 nps 34140884 hashfull 952 tbhits 0 time 193489 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 61 multipv 1 score cp 197 upperbound nodes 7235760370 nps 34091546 hashfull 971 tbhits 0 time 212245 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 93 multipv 1 score cp 115 upperbound nodes 8282224298 nps 33991046 hashfull 980 tbhits 0 time 243659 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 93 multipv 1 score cp 10 upperbound nodes 9848044552 nps 33937943 hashfull 995 tbhits 0 time 290178 pv c2c6 c8d7
info depth 42 currmove c2c6 currmovenumber 1
info depth 42 seldepth 93 multipv 1 score cp 0 nodes 10385199007 nps 33892150 hashfull 997 tbhits 0 time 306419 pv c2c6 c8d7 c6b6 d8c7 b6d6 c7b8 b5b6 f7e8 h6h3 e8g6 d6d7 g6g5 d2e2 g5g6 d7g7 g6c2 e2f3 c2d3 f3g4 d3f5 g4g3 f5d3 g3h2 d3d2 h3g2 g8h8 h2g3 d2d4 g2e2 d4a4 f6f7 a4h4 g3f3 h4h3 f3f2 h3h2 f2f1 h2h1 g7g1 h1h3 e2g2 h3f5 g2f2 f5d3 f1e1 d3c3 e1f1 c3d3

[Ron Langeveld]

My inquiry was about the functionality of the McBrain output and not about the actual moves. Sorry if that wasn't immediately obvious.

[MikeB]

My inquiry was about the functionality of the McBrain output and not about the actual moves. Sorry if that wasn't immediately obvious.

The output I displayed is from xboard which shows output in a different format than Stockfish, one it has the pieces moves and it is not entirely algebraic like the normal stockfish output is. But there was no change to the normal stockfish output code. Apparently when everything happens at the same depth( fail high, fail low, and then fail high again) happens at the same depth, Stockfish may not provide the failed low pv, but if one does want to see the failed pv. just do a search on the move that failed low.

Code: Select all

go infinite searchmoves c2c6 
info depth 37 seldepth 19 multipv 1 score cp 0 nodes 1351949086 nps 26003021 hashfull 753 tbhits 1211005 time 51992 pv c2c6 c8d7 c6b6 d8c7 b6a6 c7b7 a6a5 g8g6 h6h4 g6g8 a5a6 f7g6 a4a5 g8c8 a6b6 b7a7 b6a6 a7b7

[MikeGL]

Hi Mike!

C, Sullivan's post:
www.rybkaforum.net/cgi-bin/rybkaforum/t ... pid=577955

Wow, 35...g5! is an amazing resource. I wonder if it can be spotted easily by SF9. Not sure what to call that type of pawn sacrifice, not a gambit nor a vacating sacrifice. Maybe a deep engine move to remove an outside passer (h-pawn).

Yet a trap only, as CSullivan writes in his post, after 37.Kc1(!)
it loses completely too.
But the easy to be made blunder 37.Rc6(?)
would indeed cost the half point, so the given position is a good one for testing.

Indeed you are correct Peter. Thanks.