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Subject: Re: White's Best Move...?

Author: John Merlino

Date: 09:24:18 04/11/05

Go up one level in this thread


On April 11, 2005 at 09:05:39, chandler yergin wrote:

>On April 11, 2005 at 05:41:59, pavel wrote:
>
>>On April 10, 2005 at 20:52:17, John Merlino wrote:
>>
>>>On April 10, 2005 at 19:55:40, Rob Basham wrote:
>>>
>>>>[D]2r1r2k/4R1pp/pb6/1p6/2nqN1QB/P5PP/1PB4K/5R2 w - - 0 1
>>>>
>>>>
>>>>White mates in about 9 or 14...
>>>>
>>>>Best move is..
>>>>
>>>>Qf5, Bf6, or Rxe8+.....?
>>>>
>>>>Thanks
>>>>
>>>>Rob
>>>>
>>>>Thanks to John Merlino for your help on these test diagrams...:-)
>>>
>>>It takes exactly one minute for CMX Yoda v25 on a P4-2.4 to announce Mate in 9
>>>with Bf6:
>>>
>>>Time	Depth	Score	Positions	Moves
>>>0:00	1/3	10.52	4465		1.Bf6 Rxe7 2.Bxd4 Rd8
>>>0:00	1/4	10.39	9920		1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qf3
>>>0:00	1/5	10.54	51151		1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qg5 Red7
>>>0:00	1/5	12.04	189663		1.Qf5 Qe5 2.Rxe5 Nxe5 3.Nd6 Rxc2+
>>>					4.Qxc2
>>>0:01	1/6	13.31	312119		1.Qf5 Qe5 2.Rxe5 Nxe5 3.Nd6 Rxc2+
>>>					4.Qxc2 Rb8 5.Qe4 Ng6
>>>0:03	1/7	14.55	858973		1.Qf5 Qd5 2.Rxe8+ Rxe8 3.Qxd5 Ne3
>>>					4.Qf7 Nxf1+ 5.Qxf1 Bd4 6.Qf7
>>>0:11	1/8	16.40	2967418		1.Qf5 Qe5 2.Rxe5 Nxe5 3.Nd6 Rxc2+
>>>					4.Qxc2 Rb8 5.Nc8 Ng6 6.Nxb6 Nxh4
>>>					7.gxh4
>>>0:30	1/9	17.20	8063147		1.Qf5 Qe5 2.Rxe5 Nxe5 3.Nd6 Rxc2+
>>>					4.Qxc2 Rg8 5.Qf5 Bc5 6.Qxe5 Bxd6
>>>					7.Qxd6 a5
>>>1:00	1/9	Mate09	16434288	1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne5
>>>					4.Qe4 Ng6 5.Qxe7 h6 6.Nf7+ Kh7
>>>					7.Bxg6+ Kxg6 8.Qe4+ Kh5 9.Qg4#
>>>1:04	1/10	Mate09	17702274	1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne3
>>>					4.Qe4 Nxf1+ 5.Kg2 Ne3+ 6.Bxe3 g6
>>>					7.Qxe7 Rg7 8.Qf8+ Rg8 9.Nf7#
>>>1:34	1/11	Mate09	27485404	1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne3
>>>					4.Qe4 Nxf1+ 5.Kg2 Ne3+ 6.Bxe3 g6
>>>					7.Qxe7 Rg7 8.Qf8+ Rg8 9.Nf7#
>>>
>>>It appears that both Rxe8+ and Qf5 are Mates in about 15 moves.
>>>
>>>jm
>>
>>
>>Only Junior finds this mate faster.
>
>For comparison, here's Shredder
>Finds Mate
>Depth: 15/36   00:00:43  15751kN
>Now that's fast..
>
>
>
>
>New game,
>[D]2r1r2k/4R1pp/pb6/1p6/2nqN1QB/P5PP/1PB4K/5R2 w - - 0 1
>
>Analysis by Shredder 8:
>
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bc3 Be3
>  +-  (9.95)   Depth: 5/16   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>  +-  (9.95)   Depth: 6/19   00:00:00
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5 5.Kg2
>  +-  (10.04)   Depth: 7/18   00:00:00  59kN
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5 5.Qg5 Re5
>  +-  (10.13)   Depth: 8/20   00:00:00  130kN
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Nf6 Nd2 4.Rf5 Re2+ 5.Rf2 Nf1+ 6.Kg2 Rxf2+ 7.Kxf2 Ne3
>  +-  (10.20)   Depth: 9/20   00:00:01  259kN
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.Nd6 Na4 5.Nxe8 Rxe8
>  +-  (10.45)   Depth: 10/26   00:00:01  488kN
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.Nd6 Re2+ 5.Kg1 Nd5 6.Nxe8 Rg2+ 7.Kxg2 Nf4+
>8.gxf4
>  +-  (10.95)   Depth: 10/26   00:00:01  527kN
>1.Bf6 Rxe7 2.Bxd4 Ra8 3.Qh4 Re6 4.Nc3 h6 5.Bxg7+ Kg8 6.Bxh6 Nxb2 7.Qg4+ Rg6
>8.Bxg6
>  +-  (15.46)   Depth: 10/34   00:00:04  1467kN
>1.Bf6 Rxe7 2.Bxd4 Rg8 3.Bxb6 Nxb6 4.Nd6 h6 5.Qg6 Nc4 6.Nf7+ Rxf7 7.Qh7#
>  +-  (15.70)   Depth: 11/32   00:00:07  2343kN
>1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne3 4.Bxe3 Bc7 5.Nf7+ Rxf7 6.Rxf7
>  +-  (15.95)   Depth: 12/41   00:00:14  4606kN
>1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne3 4.Bxe3 Bc7 5.Nf7+ Rxf7 6.Rxf7 Be5
>  +-  (16.45)   Depth: 12/41   00:00:14  4749kN
>1.Bf6 Qxf6 2.Nxf6 Bg1+ 3.Kxg1 Rg8 4.Nxg8 Nxb2 5.Qxg7#
>  +-  (#152)   Depth: 12/42   00:00:22  7641kN
>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 Ree8 4.Nc3 Re2+ 5.Nxe2 h6 6.Kh1 Rxd4 7.Rf8#
>  +-  (#152)   Depth: 13/18   00:00:23  7840kN
>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 Bxd4 4.Qxe7 Rg8 5.Rf8 Bg1+ 6.Kxg1 Nd6 7.Qxd6 b4
>8.Rxg8+ Kxg8 9.Qd8+ Kf7
>  +-  (#150)   Depth: 14/40   00:00:43  15586kN
>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 Bxd4 4.Qxe7 Rg8 5.Rf8 Bc5 6.Nxc5 Nd6 7.Qxd6 b4
>8.Rxg8+ Kxg8 9.Qe6+ Kf8 10.Nd7#
>  +-  (#150)   Depth: 15/36   00:00:43  15751kN
>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 h5 4.Qxe7 Ne5 5.Qxe5 Bxd4 6.Qxh5+ Kg8 7.Bb3+ Rd5
>8.Bxd5#
>  +-  (#150)   Depth: 16/38   00:00:47  17089kN
>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Qf5 Kg8 4.Ng5 g6 5.Qd5+ Re6 6.Rf8+ Kxf8 7.Qf3+ Ke7
>8.Qb7+ Bc7 9.Qxc7+ Kf8 10.Qg7#
>  +-  (#150)   Depth: 17/36   00:00:49  17858kN
>
>(,  11.04.2005)

Shredder's output is incredibly bizarre here. The position is a Mate in 9, but
not a single PV shows mate in 9 moves (although there are mates shown in 10, 7
and even 5 moves!??).

Conclusion: Shredder found the best move, but did NOT conclusively find the mate
in 9.

jm



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