Author: Dann Corbit
Date: 20:44:10 05/21/04
Go up one level in this thread
On May 21, 2004 at 22:12:00, Uri Blass wrote:
>On May 21, 2004 at 20:30:53, Dann Corbit wrote:
>
>>On May 21, 2004 at 20:25:04, Uri Blass wrote:
>>
>>>On May 21, 2004 at 20:17:21, Mike Byrne wrote:
>>>
>>>>On May 21, 2004 at 19:32:33, George Tsavdaris wrote:
>>>>
>>>>>Black threatens mate and white's Queen. What white should play?
>>>>>Give it's Queen of course! Qf4!! and white is winning.
>>>>>
>>>>> Impressive for humans but not for computers, as any chess engine can solve
>>>>>this in seconds....
>>>>>
>>>>>[D]1kbr3r/pp6/8/P1n2ppq/2N3n1/R3Q1P1/3B1P2/2R2BK1 w - - 0 1
>>>>
>>>>
>>>>Black(1): mt 2
>>>>max threads set to 2
>>>>Black(1): 1kbr3r/pp6/8/P1n2ppq/2N3n1/R3Q1P1/3B1P2/2R2BK1 w - - 0 1
>>>>White(1): go
>>>> clearing hash tables
>>>> time surplus 29.92 time limit 1666:39 (1666:39)
>>>> depth time score variation (1)
>>>>starting thread 1
>>>> 1 0.00 2.84 1. Qxc5
>>>> 1-> 0.00 2.84 1. Qxc5
>>>> 2 0.00 -1 1. Qxc5
>>>> 2 0.00 -Mat01 1. Qxc5 Qh1#
>>>> 2 0.00 -9.26 1. Qe5+ Nxe5 2. Nxe5 Rxd2 3. Rxc5
>>>> 2 0.02 -8.25 1. Bg2 Nxe3 2. Rxe3
>>>> 2-> 0.02 -8.25 1. Bg2 Nxe3 2. Rxe3
>>>> 3 0.02 -8.25 1. Bg2 Nxe3 2. Rxe3
>>>> 3-> 0.04 -8.25 1. Bg2 Nxe3 2. Rxe3
>>>> 4 0.04 -8.62 1. Bg2 Nxe3 2. Rxe3 Qh2+ 3. Kf1 Nd3
>>>> 4-> 0.05 -8.62 1. Bg2 Nxe3 2. Rxe3 Qh2+ 3. Kf1 Nd3
>>>> 5 0.07 -8.58 1. Bg2 Nxe3 2. Rxe3 Nd3 3. Rc2
>>>> 5 0.07 -8.29 1. Qf4+ gxf4 2. Bxf4+ Ka8 3. Nb6+ axb6
>>>> 4. axb6+ Na6 5. Rxc8+ Rxc8 6. Rxa6+
>>>> bxa6 7. Bg2+ Rc6 8. Bxc6#
>>>> 5-> 0.08 -8.29 1. Qf4+ gxf4 2. Bxf4+ Ka8 3. Nb6+ axb6
>>>> 4. axb6+ Na6 5. Rxc8+ Rxc8 6. Rxa6+
>>>> bxa6 7. Bg2+ Rc6 8. Bxc6# (s=9)
>>>
>>>
>>>What is this?
>>>Crafty evaluates mate as -8.29 pawns?
>>>
>>>Movei always evaluates mate as Mate-ply when ply is the number of plies from the
>>>root position.
>>
>>Crafty has not resolved the mate yet. Crafty is sure of a win (at +8 pawns, it
>>is almost impossible to lose). But a 5 ply search with 8 hundredths of a second
>>has not determined for a certainty that there is no alternative to checkmate.
>>
>>It is also possible to see a pv with a # in it that is not a checkmate at all.
>>So that knife cuts both ways.
>
>no
>8.29 at depth 5 is for black when the mate is for white.
You are right. It took 1/2 second at ply 8 to see the mate in 11:
8 0.54 Mat11 1. Qf4+ gxf4 2. Bxf4+ Ne5 3. Bxe5+
Rd6 4. Bxd6+ Ka8 5. Nb6+ axb6 6. axb6+
Na6 7. Rxc8+ Rxc8 8. Rxa6+ bxa6 9.
Bg2+ Qf3 10. Bxf3+ Rc6 11. Bxc6#
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