Mate in ??

[MOBMAT]

I had this position...
[d]5R2/8/7P/p7/6P1/5K1b/1kP5/4r3 w - - 0 1
... in my list of unknowns and it seems to have come from the ECE3 test suite, at least that is what Dann provided over a decade ago at this site:

http://www.open-aurec.com/wbforum/viewt ... 23#p185631

Well, the first move (Rb8+) is easy for a computer, as it eventually avoids the draw, but finding the mate score was an ordeal. The only engine I could get a score out of was H6/T1 with Nalimov-6 which settled on M52 at depth 24 in 34 seconds on my PC (see signature block for details).

I then tried all the usually suspects and although a lot of them found the win (Syzygy engines), none could resolve the win to a score.

I only have 16Gb hash, so perhaps those with mega builds can see if any other engines can find it.

Code: Select all

FEN: 5R2/8/7P/p7/6P1/5K1b/1kP5/4r3 w - - 0 1

Houdini 6 (N6):
 8	00:00	 218,945	2,065,000	+0.34	1.Rf5 Rg1 2.Rb5+ Kc3 3.g5 Rf1+ 4.Kg3 Bf5
 9	00:00	 437,890	2,329,000	+0.05	1.Rf5 a4 2.Rb5+ Kxc2 3.g5 Rf1+ 4.Ke3 Bf5 5.Ra5 a3 6.Rxa3
 10	00:00	 510,297	2,180,000	+0.29	1.Rf5 Rf1+ 2.Ke4 Re1+ 3.Kf4 Rf1+ 4.Ke5 Re1+ 5.Kf6 Bxg4 6.Rf4
 11	00:00	 1,198,867	2,110,000	+0.37	1.Rb8+ Kxc2 2.g5 Rf1+ 3.Ke2 Rh1 4.Ra8 Be6 5.Rxa5 Kc3 6.Re5 Bf7 7.Re7 Bg6 8.Rg7
 12	00:01	 2,642,440	2,317,000	+0.10	1.Rb8+ Kxc2 2.g5 Rf1+ 3.Ke3 Re1+ 4.Kf2 Rh1 5.Ra8 Be6 6.Rxa5 Kd3 7.Re5 Bc8 8.Kf3
 13	00:01	 3,085,763	2,431,000	 0.00	1.Rb8+ Kxc2 2.g5 Rf1+ 3.Ke3 Re1+ 4.Kf2 Rh1 5.Ra8 Be6 6.Rxa5 Kd3 7.Re5 Bc8 8.Kg2 Rh5
 14	00:01	 3,281,810	2,450,000	 0.00	1.Rb8+ Kxc2 2.g5 Rf1+ 3.Ke3 Re1+ 4.Kf2 Rh1 5.Ra8 Be6 6.Rxa5 Kd3 7.Re5 Bc8 8.Kg2 Rh5
 15	00:01	 3,807,147	2,394,000	 0.00	1.Rb8+ Kxc2 2.g5 Rf1+ 3.Ke3 Re1+ 4.Kf2 Rh1 5.Ra8 Be6 6.Rxa5 Kd3 7.Re5 Bc8 8.Kg2 Rh5
 16	00:03	 7,188,467	2,179,000	+3.53	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.g5 Bc8 10.Qd1+ Kb2 11.Qe2+ Kb3 12.Qe3+ Kb2 13.Qf2+ Kb1 14.Qg1+ Ka2
 17	00:03	 7,854,162	2,190,000	+3.54	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.g5 Bc8 10.Qd1+ Kb2 11.Qe2+ Kb1 12.Qe4+ Kb2 13.Qe5+ Ka2 14.Qh2+ Ka1 15.Qg1+ Ka2
 18+	00:04	 9,160,378	2,256,000	+4.41	1.Rb8+
 18+	00:04	 9,663,546	2,282,000	+4.77	1.Rb8+
 18-	00:04	 9,981,530	2,290,000	+4.48	1.Rb8+ Kxc2
 18+	00:04	 10,692,202	2,300,000	+4.86	1.Rb8+
 18-	00:04	 10,827,268	2,306,000	+4.37	1.Rb8+ Kxc2
 18+	00:04	 11,186,932	2,332,000	+5.00	1.Rb8+
 18	00:04	 11,515,721	2,361,000	+5.35	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rb2 6.h8Q Rb3+ 7.Kh4 Kb1 8.Qd4 Ra3 9.Qg1+ Ka2 10.Qf2+ Ka1 11.Qc2 a4 12.g5 Rb3 13.Qc4 Ra3 14.Qd4+ Kb1
 18	00:04	 11,523,780	2,360,000	+5.35	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rb2 6.h8Q Rb3+ 7.Kh4 Kb1 8.Qd4 Ra3 9.Qg1+ Ka2 10.Qf2+ Ka1 11.Qc2 a4 12.g5 Rb3 13.Qc4 Ra3 14.Qd4+ Kb1
 19+	00:05	 11,905,017	2,379,000	+5.42	1.Rb8+
 19+	00:05	 12,135,298	2,397,000	+5.49	1.Rb8+
 19+	00:05	 13,118,612	2,478,000	+5.95	1.Rb8+
 19-	00:05	 13,261,660	2,482,000	+5.79	1.Rb8+ Kxc2
 19-	00:05	 13,673,498	2,476,000	+4.96	1.Rb8+ Kxc2
 19+	00:05	 13,899,286	2,479,000	+5.34	1.Rb8+
 19+	00:06	 15,788,402	2,524,000	+7.10	1.Rb8+
 19-	00:06	 15,828,195	2,527,000	+6.29	1.Rb8+ Kxc2
 19	00:06	 16,013,208	2,530,000	+6.18	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.Qc5 Ka2 10.g5 a4 11.Qd4 Kb1 12.g6 Ka2 13.Qd2+ Ka1 14.Qc1+
 19	00:06	 16,013,853	2,531,000	+6.18	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.Qc5 Ka2 10.g5 a4 11.Qd4 Kb1 12.g6 Ka2 13.Qd2+ Ka1 14.Qc1+
 20+	00:06	 16,306,226	2,539,000	+6.25	1.Rb8+
 20-	00:06	 16,494,874	2,543,000	+6.18	1.Rb8+ Kxc2
 20+	00:06	 17,477,290	2,597,000	+6.25	1.Rb8+
 20+	00:09	 27,380,052	2,765,000	+10.08	1.Rb8+
 20-	00:09	 27,435,299	2,764,000	+9.27	1.Rb8+ Kxc2
 20+	00:10	 30,384,474	2,857,000	+10.30	1.Rb8+
 20-	00:10	 30,448,186	2,860,000	+8.99	1.Rb8+ Kxc2
 20+	00:11	 32,871,550	2,888,000	+10.64	1.Rb8+
 20-	00:11	 33,027,827	2,888,000	+8.56	1.Rb8+ Kxc2
 20+	00:12	 35,967,633	2,920,000	+11.18	1.Rb8+
 20	00:12	 38,311,361	2,987,000	+11.38	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.Qc5 Kb2 10.g5 Ka2 11.g6 a4 12.Qf2+ Kb1 13.Qe1+ Kc2 14.Qe4+ Kb2 15.Qb4+
 20	00:12	 38,327,005	2,987,000	+11.38	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.Qc5 Kb2 10.g5 Ka2 11.g6 a4 12.Qf2+ Kb1 13.Qe1+ Kc2 14.Qe4+ Kb2 15.Qb4+
 21-	00:12	 38,488,596	2,991,000	+11.31	1.Rb8+ Kxc2
 21-	00:13	 39,039,730	3,000,000	+11.24	1.Rb8+ Kxc2
 21-	00:13	 40,303,096	3,013,000	+7.31	1.Rb8+ Kxc2
 21+	00:13	 41,483,208	3,011,000	+8.11	1.Rb8+
 21+	00:13	 41,926,653	3,018,000	+9.69	1.Rb8+
 21-	00:13	 42,040,594	3,018,000	+8.39	1.Rb8+ Kxc2
 21+	00:14	 42,722,408	3,022,000	+10.04	1.Rb8+
 21-	00:14	 42,780,950	3,023,000	+7.96	1.Rb8+ Kxc2
 21+	00:14	 43,226,750	3,029,000	+10.57	1.Rb8+
 21	00:14	 45,396,979	3,075,000	+11.94	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.Qc5 Ka2 10.g5 a4 11.g6 Rb3 12.Qd5 Bf1 13.g7 Ka3 14.Qd6+ Kb2
 21	00:14	 45,398,340	3,075,000	+11.94	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kc1 4.Rh2 Rxh2 5.Kg3 Rd2 6.h8Q Rd3+ 7.Kh4 Ra3 8.Qd4 Kb1 9.Qc5 Ka2 10.g5 a4 11.g6 Rb3 12.Qd5 Bf1 13.g7 Ka3 14.Qd6+ Kb2
 22-	00:14	 45,544,210	3,077,000	+11.87	1.Rb8+ Kxc2
 22-	00:14	 45,684,675	3,077,000	+11.80	1.Rb8+ Kxc2
 22-	00:15	 47,785,069	3,098,000	+8.85	1.Rb8+ Kxc2
 22+	00:15	 49,236,037	3,124,000	+9.48	1.Rb8+
 22-	00:15	 49,347,482	3,126,000	+8.67	1.Rb8+ Kxc2
 22+	00:16	 50,217,121	3,137,000	+9.70	1.Rb8+
 22+	00:16	 51,883,929	3,151,000	+11.70	1.Rb8+
 22-	00:16	 52,011,315	3,151,000	+10.05	1.Rb8+ Kxc2
 22+	00:16	 52,830,148	3,154,000	+12.13	1.Rb8+
 22-	00:16	 52,884,076	3,154,000	+9.51	1.Rb8+ Kxc2
 22+	00:16	 53,652,905	3,169,000	+12.80	1.Rb8+
 22-	00:16	 53,691,137	3,169,000	+8.67	1.Rb8+ Kxc2
 22+	00:17	 55,414,061	3,198,000	+13.85	1.Rb8+
 22	00:23	 73,493,645	3,092,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 22	00:23	 73,509,308	3,092,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 23-	00:24	 74,157,195	3,086,000	+M59	1.Rb8+ Kxc2
 23-	00:30	 93,707,744	3,046,000	+M66	1.Rb8+ Kxc2
 23-	00:30	 94,209,940	3,049,000	+15.05	1.Rb8+ Kxc2
 23	00:32	 98,236,470	3,033,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 23	00:32	 98,236,614	3,033,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 24-	00:32	 98,394,481	3,032,000	+M59	1.Rb8+ Kxc2
 24-	00:32	 98,506,581	3,033,000	+M66	1.Rb8+ Kxc2
 24-	00:32	 99,554,069	3,034,000	+93.60	1.Rb8+ Kc1
 24	00:34	 106,179,770	3,082,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 24	00:34	 106,180,302	3,082,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 25	00:36	 111,429,180	3,077,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 25	00:36	 111,477,779	3,076,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 26	00:41	 129,379,459	3,135,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 26	00:41	 129,428,896	3,135,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 27	00:46	 145,870,539	3,120,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 27	00:46	 145,961,089	3,120,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 28	00:49	 156,090,022	3,162,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 28	00:49	 156,276,108	3,163,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 29	01:02	 196,010,008	3,125,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 29	01:02	 196,268,339	3,125,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 30	01:07	 215,917,538	3,182,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 30	01:08	 218,687,417	3,185,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 31	01:21	 261,575,243	3,208,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 31	01:21	 262,581,776	3,209,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 32	01:46	 351,976,574	3,320,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 32	01:46	 355,586,348	3,327,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 33	01:54	 387,253,562	3,391,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 33	01:55	 391,091,925	3,391,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 34	02:44	 559,071,932	3,407,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 34	02:45	 562,075,702	3,404,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 35	05:36	1,092,371,697	3,244,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 35	05:38	1,096,036,190	3,240,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 36	06:13	1,208,160,906	3,233,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 36	06:25	1,242,908,134	3,227,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 37	06:46	1,315,925,570	3,238,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 37	06:50	1,329,814,668	3,240,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 38	08:18	1,607,261,844	3,222,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5
 38	08:39	1,669,141,693	3,212,000	+M52	1.Rb8+ Kxc2 2.h7 Rh1 3.Rb2+ Kd3 4.Rh2 Rxh2 5.Kg3 Re2 6.h8Q Re3+ 7.Kh4 Bf1 8.Qd8+ Kc2 9.Qxa5

[peter]

none could resolve the win to a score.

Here's your mating score, but something tells me, you yet wont be fully confident still

5R2/8/7P/p7/6P1/5K1b/1kP5/4r3 w - - 0 1

Analysis by Xiphos 0.6 SSE:

1.Tb8+ Kxc2 2.h7 Th1 3.Tb2+ Kd3 4.Th2 Txh2 5.Kg3 Te2 6.h8D Te3+ 7.Kh4 Lg2 8.Dd8+ Kc2 9.Dxa5 Th3+ 10.Kg5 Kb3 11.Db5+ Ka3 12.Dc5+ Kb3 13.Kf4 Lf1 14.Db6+ Kc3 15.g5 Lc4 16.Da5+ Kb3 17.Dc5 Kc3 18.Da3+ Lb3 19.Dd6 Th2 20.Kg3 Te2 21.Dc5+ Kb2 22.Dd4+ Kc2 23.Kh4 Td2 24.De4+ Td3 25.De5 Td5 26.Df6 Td1 27.Df2+ Kb1 28.g6
+- (#342) Tiefe: 45 00:22:44 42232MN, tb=678879973

Anyhow, if there won't be much better moves to be found for the first 4 ones, according to 7men, which is reached there already, it's #51.

I, for my personal interest in such not anything else but long mates, would be confident with such "results". How much sense is in demanding an engine to find the best line for 51 moves with so many unforced ones among them, and then of course all at once too?

Ok, if you want to have an engine specialised in solving mate in x problems only, but game playing ones? I don't believe in Elo only neither, but here I'd rather have some more Elo than a search, that would fit such "problems", as said, if it isn't for specialised search. BTW with complete 7men tbs SF would solve the 4 moves left yet still maybe, I can't try that. But i'd call such positions at least more a matter of tbs- usage then of mate solving search of its own. Xiphos, as it seems, has both.

[mmt]

Not really what you're asking but with the 7-piece TBs SF solves it in seconds. I suppose other programs would too. I can't tell you in how many moves because I only have WDL 7-piece TBs.

[MOBMAT]

Not really what you're asking but with the 7-piece TBs SF solves it in seconds. I suppose other programs would too. I can't tell you in how many moves because I only have WDL 7-piece TBs.

Well, H6 found it pretty darned fast with Nalimov 6, so, I would assume any engine with Syzygy 7 would too.
I don't have an HD that will hold the 7-man set. I have all the 6-men sets on a M2 SSD, and that purchase was at the limit of my current budget for storage. I know, wait a year and 8TB drives will be dirt cheap.

I think more RAM would help my system the most, I only have 32Gb and use 16Gb for hash as I've found that the engines are still eating up a LOT more memory than that. I think having all the TB files open is the culprit, but I haven't proved that yet.

[mmt]

I think more RAM would help my system the most, I only have 32Gb and use 16Gb for hash as I've found that the engines are still eating up a LOT more memory than that. I think having all the TB files open is the culprit, but I haven't proved that yet.

I have a lot of RAM on my workstation and I was thinking to do a test of how much a very large hashtable helps. I need to come up with a good plan to test it though.

[MOBMAT]

I think more RAM would help my system the most, I only have 32Gb and use 16Gb for hash as I've found that the engines are still eating up a LOT more memory than that. I think having all the TB files open is the culprit, but I haven't proved that yet.

I have a lot of RAM on my workstation and I was thinking to do a test of how much a very large hashtable helps. I need to come up with a good plan to test it though.

Well, If the Hash utilization gets to 100% before the engine finds a solution, you probably don't have enough RAM!

[Nordlandia]

Maybe Houdini 6 with Nalimov 6 is able to reach mate score with good accuracy. I have Nalimov 6 on external drive as backup.

But i find it cumbersome to have to remove half of the selected syzygy 7 files on my 2 TB M.2 just to check for this one. I i'm planning to purchase another SSD solely for Nalimov once time allow it.

[peter]

But i find it cumbersome to have to remove half of the selected syzygy 7 files on my 2 TB M.2 just to check for this one. I i'm planning to purchase another SSD solely for Nalimov once time allow it.

I'm not planning to purchase another SSD solely for "problems" like this one, which is nothing but a long way to mate from 7men position reached after just 4 moves.
Any good engine with full 7men +DTM info stored will find the mate in 51 quickly, btw. here's the full line:

5R2/8/7P/p7/6P1/5K1b/1kP5/4r3 w - - 0 1

1. Rb8+ Kxc2 2. h7 Rh1 3. Rb2+ Kd3 4. Rh2 Rxh2 5. Kg3 Re2 6. h8=Q Re3+ 7. Kh4
Bf1 8. Qd8+ Ke2 9. Qxa5 Rh3+ 10. Kg5 Rf3 11. Kh5 Rh3+ 12. Kg6 Rf3 13. g5 Kf2
14. Qc5+ Ke1 15. Qd5 Be2 16. Kg7 Rd3 17. Qa5+ Kd1 18. g6 Rf3 19. Qa1+ Kc2 20.
Qa2+ Kd1 21. Qb1+ Kd2 22. Qb2+ Ke1 23. Qb4+ Kf1 24. Qd4 Rd3 25. Qe4 Rf3 26. Kh6
Bd1 27. g7 Rh3+ 28. Kg5 Bb3 29. Kg4 Rc3 30. Qe5 Rd3 31. Kf4 Bd5 32. Qxd5 Rxd5
33. g8=Q Rd2 34. Qc4+ Kf2 35. Qe4 Re2 36. Qd4+ Kg2 37. Kg4 Rf2 38. Qd1 Rf8 39.
Qd5+ Kf1 40. Kg3 Ke1 41. Qc5 Re8 42. Qa5+ Kd1 43. Qa4+ Kc1 44. Qxe8 Kc2 45. Qb8
Kc3 46. Qb5 Kc2 47. Qb4 Kc1 48. Kf3 Kc2 49. Ke3 Kc1 50. Kd3 Kd1 51. Qb1# 1-0

Just to spare looking up at Losomosov after 4...Rxh2

Bored regards