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Subject: Re: Deep Blue versus Deep Thought - a missing position

Author: John Merlino

Date: 09:28:08 08/31/01

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On August 31, 2001 at 11:11:29, Uri Blass wrote:

>On August 31, 2001 at 10:56:24, John Merlino wrote:
>
>>On August 30, 2001 at 09:36:26, Uri Blass wrote:
>>
>>>On August 30, 2001 at 07:45:34, Kim Roper Jensen wrote:
>>>
>>>>Hi
>>>>
>>>>If my memory(heavily fragmented) serves me well there was some games, where the
>>>>DB played against DT, and in one of them DB "announced" mate in 18, a very
>>>>complicated position where the mate consisted of quiet moves and some
>>>>counterchecks.
>>>>
>>>>Are there anyone that have this position ?? Or is my memory corrupted  ??? :)
>>>>
>>>>With regards
>>>
>>>I know of no public games between DB and DT.
>>>
>>>I had a mate in 18 against abir har aven
>>>when no commercial program can see the mate and I found the mate only
>>>by going forward and backward with chessmaster
>>>that is the best in finding mates.
>>>
>>>chessmaster6000(ss=10)could not find the mate in a few hours
>>>on PIII850 and it means that probably no program can do it
>>>in a reasonable time.
>>>
>>>I posted the position some weeks ago and yace also could see the mate
>>>after going forward and backward but not from the root position.
>>>
>>>Uri
>>
>>This is very strange, because Chessmaster 8000 (default personality) on my
>>PIII-733, has no problem and finds the mate in 18 in 2 seconds (although, for
>>some reason, it only reports the first 16 of the moves....hmmm.... I think I
>>remember Johan saying something about a PV having a maximum number of plies and
>>now I believe it is 31):
>
>
>We talk about different positions
>I talk about the position that I posted some weeks ago.
>
>Uri

That will teach me to read the WHOLE post, eh?

Here's CM8000's analysis of the REAL position:

Time	Depth	Score	Positions	Moves
0:00	2/5	-4.56	31036		1...Ng4+ 2. Kf1 Ne3+ 3. Qxe3 Rxe3
					4. Rxh3 Qxh3+ 5. Kf2 Rxd3 6. f7
					Rd2+ 7. Ke3
0:02	2/6	-4.72	181189		1...Ng4+ 2. Kf1 Ne3+ 3. Qxe3 Rxe3
					4. Rxh3 Qxh3+ 5. Kf2 Rxd3 6. f7
					Qh6 7. Ne2 Qf8
0:06	3/7	-4.46	775309		1...Ng4+ 2. Kf1 Ne3+ 3. Qxe3 Rxe3
					4. Rxh3 Qxh3+ 5. Kf2 Rxd3 6. f7
					Qh6 7. Ne2 Qh2+ 8. Rg2
0:25	3/8	-4.55	3153074		1...Ng4+ 2. Kf1 Ne3+ 3. Qxe3 Rxe3
					4. Rxh3 Qxh3+ 5. Kf2 Rxd3 6. f7
					Qh6 7. Ne2 Kd7 8. Rg8 Qh4+ 9. Kg2
1:15	4/9	-5.20	9714196		1...Ng4+ 2. Kf1 Ne3+ 3. Qxe3 Rxe3
					4. Rxh3 Qxh3+ 5. Kf2 Re8 6. Kf3
					Qe6 7. Ne4 Qxa2 8. Rg2 Qf7
11:58	5/10	-13.45	98373872	1...Ng4+ 2. Kf1 Ne3+ 3. Ke1 Rxh1
					4. Qf2 Ng4+ 5. Kd2 Rh2 6. f7 Rxf2+
					7. Kc3 Rd8 8. Nf5 Qf6 9. Rxg4 Qxf5
39:08	6/11	-13.77	324123804	1...Ng4+ 2. Kf1 Ne3+ 3. Ke1 Rxh1
					4. Qf2 Ng4+ 5. Kd2 Rh2 6. Qxh2
					Qxh2+ 7. Kc3 Qxg1 8. Ne4 Rd8 9.
					Kc2 Qxd4

Notice that it does eventually find 3.Ke1 as better than 3.Qxe3. How long it
would take to find the mate is anybody's guess....

jm



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