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Subject: Re: Mate in 18....?

Author: John Merlino

Date: 12:40:29 12/17/02

Go up one level in this thread


On December 17, 2002 at 09:20:06, Art Basham wrote:

>White can still win..by
>1. Rxg7...etc.
>
>[D]3r1n1k/pbq1rpp1/1p2p2p/2p1P2Q/3PN1R1/1PPR4/P4PPP/6K1 w - - 0 1
>
>Not sure about how many moves to a mate!

CM9000, on a P3-733, does not announce a mate from the original position in less
than ten minutes, but it finds Rxg7 (which should be easy for any program) in
less than one second:

Time	Depth	Score	Positions	Moves
0:00	1/3	-1.86	2594		1.Nd6 Nh7 2.Rdg3 f5
0:00	1/4	-1.66	11321		1.Nd6 Ba6 2.Rf3 Ng6 3.Nxf7+ Rxf7
					4.Qxg6 Rxf3 5.gxf3 cxd4 6.cxd4
0:00	1/4	0.67	21507		1.Rxg7 Kxg7 2.Rh3 f5 3.exf6ep+
					Kg8 4.fxe7 Qxe7 5.Rg3+ Kh7 6.Ng5+
					Kg8 7.Qxh6
0:00	1/5	0.79	36639		1.Rxg7 Kxg7 2.Rh3 f6 3.exf6+ Kh8
					4.fxe7 Qxe7 5.Qxh6+ Nh7 6.Nf6
0:01	1/6	3.05	73833		1.Rxg7 Kxg7 2.Rh3 f6 3.exf6+ Kg8
					4.fxe7 Qxe7 5.Rg3+ Kh7 6.Ng5+ Kg7
					7.Nf7+ Kf6 8.Nxd8 Qxd8 9.Qxh6+ Ke7
0:02	1/7	3.26	168481		1.Rxg7 Kxg7 2.Rh3 f6 3.exf6+ Kh8
					4.fxe7 Qxe7 5.Qxh6+ Nh7 6.Nf6 Be4
					7.Nxe4 cxd4 8.Qf6+ Qxf6 9.Nxf6
0:03	1/8	3.26	321382		1.Rxg7 Kxg7 2.Rh3 f6 3.exf6+ Kh8
					4.fxe7 Qxe7 5.Qxh6+ Nh7 6.Nf6 Be4
					7.Nxe4 cxd4 8.Qf6+ Qxf6 9.Nxf6
0:07	1/9	6.43	746877		1.Rxg7 Kxg7 2.Rh3 f6 3.Qxh6+ Kf7
					4.Qh5+ Ng6 5.Qh7+ Kf8 6.Qxg6 Rf7
					7.Rh8+ Ke7 8.exf6+ Kd7 9.Qxf7+
					Kc8 10.Qxe6+ Kb8 11.Rxd8+ Qxd8
0:14	1/10	6.88	1500541		1.Rxg7 Kxg7 2.Rh3 f6 3.Qxh6+ Kf7
					4.Qh5+ Ng6 5.Qh7+ Kf8 6.Qxg6 Rf7
					7.Rh8+ Ke7 8.exf6+ Kd7 9.Qxf7+
					Kc6 10.Qxe6+ Kb5 11.Rxd8 Qxd8
0:32	2/11	7.68	3736388		1.Rxg7 Kxg7 2.Rh3 f6 3.Qxh6+ Kf7
					4.Qh5+ Ng6 5.Qh7+ Kf8 6.Qxg6 Rf7
					7.Rh8+ Ke7 8.exf6+ Kd7 9.Qxf7+
					Kc8 10.Qxe6+ Kb8 11.Rxd8+ Qxd8
					12.Qd6+ Kc8 13.Qxd8+ Kxd8
2:27	3/12	8.34	18145729	1.Rxg7 Kxg7 2.Rh3 f6 3.Qxh6+ Kf7
					4.Qh5+ Ng6 5.Qh7+ Kf8 6.Qxg6 Rf7
					7.Rh8+ Ke7 8.exf6+ Kd7 9.Qxf7+
					Kc8 10.Qxe6+ Kb8 11.Rxd8+ Qxd8
					12.Qd6+ Qc7 13.f7 Qxd6 14.Nxd6
7:50	4/13	10.97	58604447	1.Rxg7 Kxg7 2.Rh3 f6 3.Qxh6+ Kf7
					4.Qh5+ Ng6 5.Qh7+ Kf8 6.Qxg6 Rf7
					7.Rh8+ Ke7 8.exf6+ Kd7 9.Qxf7+
					Kc8 10.Qxe6+ Kb8 11.Rxd8+ Qxd8
					12.Qd6+ Qxd6 13.Nxd6 Bd5 14.f7
					Bxf7 15.Nxf7 cxd4 16.cxd4

After forcing the first several forced moves, 1.Rxg7 Kxg7 2.Rh3 f6 3.Qxh6+ Kf7
4.Qh5+ Ng6 5.Qh7+ Kf8 6.Qxg6, Black now has the option of 6...Rh7 or 6...Rf7.
And, even in this position:

[D]3r1k2/pbq1r3/1p2ppQ1/2p1P3/3PN3/1PP4R/P4PPP/6K1 b - - 0 6

CM cannot find a mate in a reasonable amount of time:

Time	Depth	Score	Positions	Moves
0:00	1/3	6.50	3221		6...Rf7 7.Rh8+ Ke7 8.exf6+ Kd7
					9.Qxf7+ Kc8 10.Qxe6+ Kb8 11.Rxd8+
					Qxd8
0:00	1/4	6.50	9861		6...Rf7 7.Rh8+ Ke7 8.exf6+ Kd7
					9.Qxf7+ Kc8 10.Qxe6+ Kb8 11.Rxd8+
					Qxd8
0:00	1/5	6.61	39477		6...Rf7 7.Rh8+ Ke7 8.exf6+ Kd7
					9.Qxf7+ Kc8 10.Qxe6+ Kb8 11.Rxd8+
					Qxd8 12.Qd6+ Kc8 13.Qxd8+ Kxd8
0:01	1/6	6.97	121149		6...Rf7 7.Nd6 fxe5 8.Rh8+ Ke7 9.Qxf7+
					Kxd6 10.dxe5+ Kc6 11.Qxe6+ Rd6
					12.exd6 Qxd6 13.Qxd6+ Kxd6 14.Rh7
0:03	1/7	7.43	344478		6...Rf7 7.Nd6 Qxd6 8.exd6 Rxd6
					9.Rh8+ Ke7 10.Rh7 Rxh7 11.Qxh7+
					Ke8 12.Qxb7 cxd4 13.Qc8+ Ke7
0:07	1/8	10.08	764432		6...Rf7 7.exf6 Ke8 8.Rh8+ Kd7 9.Qxf7+
					Kc8 10.Qxe6+ Kb8 11.Rxd8+ Qxd8
					12.Qd6+ Qxd6 13.Nxd6 Bd5 14.f7
					Bxf7 15.Nxf7 cxd4 16.cxd4
0:14	1/9	14.54	1689809		6...Rf7 7.exf6 Ke8 8.Rh8+ Kd7 9.Qxf7+
					Kc6 10.Qxe6+ Kb5 11.Rxd8 Bxe4 12.Rc8
					Qxc8 13.Qxc8 Bg6 14.a4+ Ka5 15.dxc5
0:22	1/9	12.35	2486850		6...Rh7 7.Rxh7 Qxh7 8.Qxh7 Bxe4
					9.Qh8+ Kf7 10.Qxd8 fxe5 11.Qc7+
					Ke8 12.Qxe5 Bf5 13.Qb8+ Kd7 14.dxc5
0:34	2/10	14.35	3910185		6...Rh7 7.Rxh7 Qxh7 8.Qxh7 Bxe4
					9.Qh8+ Kf7 10.Qxf6+ Ke8 11.Qxe6+
					Kf8 12.Qf6+ Ke8 13.e6 Rd7 14.exd7+
					Kxd7 15.Qf7+ Kd8 16.Qxa7 cxd4 17.Qxb6+
					Ke8 18.Qxd4
1:16	3/11	14.35	9010393		6...Rh7 7.Rxh7 Qxh7 8.Qxh7 Bxe4
					9.Qh8+ Kf7 10.Qxf6+ Ke8 11.Qxe6+
					Kf8 12.Qf6+ Ke8 13.e6 Rd7 14.exd7+
					Kxd7 15.Qf7+ Kd8 16.Qxa7 Ke8 17.Qxb6
					cxd4 18.Qxd4
3:21	4/12	14.38	24421591	6...Rh7 7.Rxh7 Qxh7 8.Qxh7 Bxe4
					9.Qh8+ Kf7 10.Qxf6+ Ke8 11.Qxe6+
					Kf8 12.Qf6+ Ke8 13.e6 Rd7 14.exd7+
					Kxd7 15.Qf7+ Kd8 16.Qxa7 cxd4 17.Qxb6+
					Ke7 18.Qxd4
10:55	5/13	15.24	79516270	6...Rh7 7.Rxh7 Qxh7 8.Qxh7 Bxe4
					9.Qh8+ Kf7 10.Qxf6+ Kg8 11.Qxd8+
					Kf7 12.Qf6+ Ke8 13.Qxe6+ Kd8 14.dxc5
					bxc5 15.Qd6+ Kc8 16.Qxc5+ Kb8 17.Qb4+
					Bb7 18.Qf8+ Kc7 19.f4

However, White also has the option of 3.exf6+, leaving Black the option of
3...Kh8 or 3...Kg8. So, I think this position has way too many options for a
comp to find a forced mate in a reasonable amount of time. Possibly overnight
with a fast CPU?

jm



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