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Subject: Re: Test Position

Author: Eelco de Groot

Date: 10:42:46 10/19/04

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On October 19, 2004 at 12:28:24, Anthony Cozzie wrote:

>On October 19, 2004 at 12:13:49, Will Singleton wrote:
>
>>On October 19, 2004 at 10:37:36, Eelco de Groot wrote:
>>
>>>On October 19, 2004 at 09:09:42, Anthony Cozzie wrote:
>>>
>>>>[D]4r3/QbpR1ppk/pr5p/1pq1P3/2p1PP2/P5PP/1P4B1/3R3K w - - 0 27
>>>>
>>>Pro Deo with custom settings also expects a draw after exchange of Rooks. Slow
>>>Celeron 500 MHz, 28 Mb HT
>>>
>>>00:00:09.3	0,00	10	1159298	Rd8 Rxd8 Rxd8 Qe3 Qb8 Bxe4 Rh8+ Kg6 >Qxc7 Bxg2+ Kxg2 Qe2+ Kg1 Qe1+ Kh2 Qf2+ Kh1 Qf1+ Kh2 Qf2+ Kh1 Qf1+ Kh2
>>
>>>00:06:18.7	0,00	13	63625473	Rd8 Rxd8 Rxd8 Qe3 Qb8 Bxe4 Rh8+ Kg6
>>>00:13:59.3	0,00	14	145222009	Rd8 Rxd8 Rxd8 Qe3 e6 Bxe4 exf7 Bxg2+
>>>
>>
>>Pro Deo looks like it has a problem.  The pv for ply 9 is no draw, Qb8 should be
>>e6.  It still shows the bogus line for ply 13, finally finding the right move in
>>ply 14.
>>
>>An engine that doesn't consider underpromos will never see the draw.
>
>
>I am not sure it is a draw.  Zappa had a draw score on Rd8 but eventually failed
>low.  Sadly I don't remember its PV :(
>
>anthony


Sofar Rebel 12 does not fail low on 3.e6. I'm taking Will's comment about the
underpromotion with a grain of salt, is the e-pawn supposed to promote to
Knight? I believe I see White can force a draw with a Knight by a perpetual, but
with a new queen it's Black who has to force a draw with perpetual check. I
remember vaguely that Rebel doesn't do underpromotions in QSearch, but not in
main search?

After 1.Rd8 Rxd8 2Rxd8 Qe3 I think Black has at least a draw after 3.e6

[D]3R4/Qbp2ppk/pr5p/1p2P3/2p1PP2/P3q1PP/1P4B1/7K w - - 1 1

Custom settings g3i3 for old Rebel 12, with Singular Extensions and what not
enabled, first plays 3.Qb8, then 3.e6

 00:00:01.0	-0,45	1	324	Rd7 Bxe4 Bxe4+ Qxe4+ Kh2
00:00:01.1	0,00	1	757	e6 Qe1+ Kh2 fxe6
00:00:01.1	0,44	1	1042	Kh2 Bxe4 Bxe4+ Qxe4 Qxc7
00:00:01.1	0,15	2	1246	Kh2 Qf2
00:00:01.1	0,15	2	1835	Qb8
00:00:01.2	0,59	2	2141	Qb8 Qe1+ Kh2
00:00:01.2	0,59	3	3233	Qb8 Qe1+ Kh2
00:00:01.3	2,09	4	10323	Qb8 Bxe4 Rh8+ Kg6 Qxc7
00:00:01.3	2,09	5	17074	Qb8 Bxe4 Rh8+ Kg6 Qxc7 Bxg2+
00:00:01.6	1,20	6	55122	Qb8 Qxe4 Rh8+ Kg6 Bxe4+ Bxe4+ Kh2 Rxb8 Rxb8
00:00:08.9	0,00	7	1217063	Qb8 Bxe4 Rh8+ Kg6 Qxc7 Bxg2+ Kxg2 Qe2+ Kh1 Qe1+ Kg2
Qe2+ Kh1 Qe1+ Kg2
00:00:10.5	0,00	8	1448937	Qb8 Bxe4 Rh8+
00:00:42.9	-0,35	9	7081631	Qb8 Bxe4 Rh8+ Kg6 Qc8 Bxg2+ Kxg2 Qe2+ Kg1 Qd1+
00:01:01.4	0,00	9	10229446	e6 Bxe4 exf7 Bxg2+ Kxg2 Qe2+ Kg1 Qe1+ Kh2 Qf2+ Kh1
Qe1+ Kh2 Qf2+ Kh1 Qe1+
00:01:23.7	0,00	10	14130917	e6 Bxe4 exf7 Bxg2+ Kxg2 Qe2+ Kg1 Qe1+
00:02:24.7	0,00	11	24982113	e6 Bxe4 exf7 Bxg2+ Kxg2 Qe2+
00:05:59.1	0,00	12	60302530	e6 Bxe4 exf7 Bxg2+ Kxg2 Qe2+ Kg1 Qe1+
00:16:55.1	0,00	13	173465343	e6 Bxe4 exf7 Bxg2+




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