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Subject: Re: Mate in 10 :-) and the aesthetics of EGTBs

Author: John Merlino

Date: 11:25:41 08/12/02

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On August 12, 2002 at 01:40:12, Harald Faber wrote:

>On August 11, 2002 at 14:26:38, John Merlino wrote:
>
>>On August 11, 2002 at 06:49:12, Harald Faber wrote:
>>
>>>On August 10, 2002 at 21:53:49, John Merlino wrote:
>>>
>>>>Here is a position from a game that Slater and I discussed in a different
>>>>thread:
>>>>
>>>>[D]3R4/8/8/8/2K5/6p1/3p1rk1/8 b - - 0 78
>>>>
>>>>In that game, Black was obviously using EGTBs and played 78...d1=Q, leading to
>>>>an EGTB mate in 22 moves (including the promotion). However, the more natural
>>>>looking move, Kf1, leads to a mate in 14, as Chessmaster 9000 shows on a
>>>>PIII-733:
>>>>
>>>>Time	Depth	Score	Positions	Moves
>>>>0:00	1/5	-8.88	14450		78...Kf1 79.Kc3 g2 80.Rd4 g1=Q
>>>>					81.Rxd2 Rxd2 82.Kxd2
>>>>0:00	2/6	-9.00	26438		78...Kf1 79.Kc3 g2 80.Rxd2 Rxd2
>>>>					81.Kxd2 g1=Q 82.Kd3 Qc5 83.Ke4 Ke2
>>>>0:00	3/7	-9.00	74581		78...Kf1 79.Kc3 g2 80.Rxd2 Rxd2
>>>>					81.Kxd2 g1=Q 82.Kd3 Qc5 83.Ke4 Ke2
>>>>0:02	4/8	-11.19	264563		78...Kf1 79.Kc3 Ke1 80.Kc4 g2 81.Re8+
>>>>					Re2 82.Rg8 d1=Q 83.Kc5 Kf1
>>>>0:05	5/9	-13.17	520117		78...Kf1 79.Kc3 Ke1 80.Kc4 g2 81.Re8+
>>>>					Re2 82.Rd8 g1=Q 83.Rxd2 Kxd2 84.Kd5
>>>>0:15	6/10	-13.30	1610302		78...Kf1 79.Kc3 Ke1 80.Kc4 g2 81.Re8+
>>>>					Re2 82.Rd8 g1=Q 83.Rd5 Qg4+ 84.Kc5
>>>>					Qc8+ 85.Kb5 d1=Q 86.Rxd1+ Kxd1
>>>>0:46	7/11	-13.35	4752680		78...Kf1 79.Kc3 Ke1 80.Kc4 g2 81.Re8+
>>>>					Re2 82.Rd8 g1=Q 83.Rd5 Qg4+ 84.Kc5
>>>>					Qc8+ 85.Kb5 Qb7+ 86.Kc5 Qc7+ 87.Kb5
>>>>					d1=Q 88.Rxd1+ Kxd1
>>>>3:06	8/12	-15.25	19391217	78...Kf1 79.Kc3 Ke1 80.Kc4 g2 81.Re8+
>>>>					Kf1 82.Rd8 g1=Q 83.Rd4 Qg8+ 84.Kc5
>>>>					Qg5+ 85.Kc4 Rf4 86.Kb3 Rxd4
>>>>9:45	9/13	-Mate14	62576834	78...Kf1 79.Kc3 Ke1 80.Kc4 g2 81.Re8+
>>>>					Re2 82.Rd8 g1=Q 83.Rd6 Qg8+ 84.Kb4
>>>>					Qb8+ 85.Kc4 Qc7+ 86.Kb5 Re5+ 87.Kb4
>>>>					Qc5+ 88.Kb3 Re3+ 89.Rd3 Rxd3+ 90.Kb2
>>>>					Qc1+ 91.Ka2 Ra3#
>>>>
>>>>Note that the first capture is 23 ply away, making it very difficult
>>>>(impossible?) to find it via tablebases. Can anybody else find the mate faster?
>>>
>>>As always... YES...
>>>
>>>GambitTiger 2 aggr.:
>>>
>>>Neue Partie
>>>3R4/8/8/8/2K5/6p1/3p1rk1/8 b - - 0 1
>>>
>>>Analysis by Gambit Tiger 2.0:
>>>
>>>1...d2-d1D 2.Td8-d2 Tf2xd2 3.Kc4-b5 Kg2-f2 4.Kb5-c4 Td2-c2+ 5.Kc4-b5 g3-g2
>>>  -+  (-30.12)   Tiefe: 8   00:00:00  187kN, tb=35
>>>1...d2-d1D
>>>  -+  (-31.02)   Tiefe: 9   00:00:00  261kN, tb=47
>>>1...d2-d1D 2.Td8xd1
>>>  -+  (-#22)   Tiefe: 9   00:00:00  283kN, tb=63
>>>1...d2-d1D 2.Td8xd1
>>>  -+  (-#22)   Tiefe: 10   00:00:02  883kN, tb=261
>>>1...Tf2-f4+ 2.Kc4-c5 d2-d1D 3.Td8xd1
>>>  -+  (-#21)   Tiefe: 10   00:00:04  1840kN, tb=425
>>>1...Tf2-f4+ 2.Kc4-c5 Tf4-f5+ 3.Kc5-c6 d2-d1D 4.Td8xd1
>>>  -+  (-#20)   Tiefe: 11   00:00:08  3238kN, tb=804
>>>1...Tf2-f4+ 2.Kc4-c5 Tf4-f5+ 3.Kc5-c6 d2-d1D 4.Td8xd1
>>>  -+  (-#20)   Tiefe: 12   00:00:19  6777kN, tb=2563
>>>1...Kg2-f1 2.Td8-d4 g3-g2 3.Td4-d6 g2-g1D 4.Kc4-b5 Tf2-f6 5.Td6xf6+
>>>  -+  (-#12)   Tiefe: 12   00:00:41  18148kN, tb=4317
>>>1...Kg2-f1 2.Kc4-c3 g3-g2 3.Td8xd2
>>>  -+  (-#10)   Tiefe: 13   00:02:25  75601kN, tb=9373
>>>
>>>(Faber, Haltern 12.08.2002)
>>>
>>>>So, SPEAKING STRICTLY AESTHETICALLY, what do you think of EGTBs when used in
>>>>game play?
>>>
>>>No problem.
>>>
>>>>jm
>>>
>>>
>>>What do you say NOW? :-)
>>
>>I assume that you WERE using tablebases here?
>
>Yes. tb=9373 means the number of TB hits.
>
>>If so, then the point was that
>>CM9000 was NOT using tablebases to find the mate.
>
>Wasn't it you who complained about progs using the TBs would NOT play accurate
>and find the shortest mate?
>
>>Additionally, you should
>>remember to always add 1 to Tiger's mate declarations. So it is really a mate in
>>11 that Tiger found.
>>
>>jm
>
>However, but no d2-d1-Q.

You are correct, and Tiger's use of TBs is excellent here, assuming that it will
do the same thing in actual game play. I expect, though, that as soon as it sees
the Mate in 22 via TBs (in less than one second) that it WILL play d1Q. Not that
there is truly anything wrong with that. In my mind, it's just not a very
attractive move....

jm



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