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Subject: Re: positions when deep thought blundered

Author: Uri Blass

Date: 15:42:07 08/20/02

Go up one level in this thread


On August 20, 2002 at 17:49:34, Robert Hyatt wrote:

>On August 20, 2002 at 17:02:52, Uri Blass wrote:
>
>>I include only gam,es from 1993
>>
>>Deep Blue - Hamann,S
>>5R2/r5pp/3N2k1/3Ppp2/2P5/p7/P5PP/2n3K1 w - - 0 38 bm Nb5
>
>What did DT play here?  I only find Nb5 and I find it instantly and stick
>with it...  score =+1.5 so apparently DT was winning here.  Did it lose by
>playing something else???

Yes it lost by Rxf5

This is a typical computer move because it wins a pawn if you do not search deep
enough when Nb5 does not win a pawn(unless you search very deep and I am sure
that your +1.5 is based on poasitional factors).

programs on the hardware of that time could not find Nb5 in 15 minutes

Movei also need time to find it(almost 5 minutes on p800 to see that Rxf5 is not
winning)

12 0 12893 23206423 f8f5 c1a2 h2h4 h7h6 f5e5 a2b4 e5e1 b4c2 e1e6 g6h5 e6e5 h5h4
e5e4 h4g5 e4e5 g5h4
12 1 22487 39275894 d6b5
12 23 25219 44104915 d6b5 a7d7 f8e8 e5e4 e8e6 g6g5 d5d6 d7d8 b5a3 c1a2 e6e7 g5f6
a3b5 d8d6 b5d6 f6e7 d6f5 e7f6



>
>                7     0.16     ++   1. Nb5!!
>                7     0.24   1.37   1. Nb5 Rb7 2. Re8 e4 3. Nxa3 Ne2+ 4.
>                                    Kf2 Rb2
>                7->   0.26   1.37   1. Nb5 Rb7 2. Re8 e4 3. Nxa3 Ne2+ 4.
>                                    Kf2 Rb2
>                8     0.41   1.18   1. Nb5 Rd7 2. Ra8 Nxa2 3. Ra6+ Kg5
>                                    4. Rxa3 Nb4 5. d6
>                8->   0.48   1.18   1. Nb5 Rd7 2. Ra8 Nxa2 3. Ra6+ Kg5
>                                    4. Rxa3 Nb4 5. d6
>                9     0.63   1.22   1. Nb5 Rd7 2. Ra8 Nxa2 3. Rxa3 Nb4
>                                    4. Kf2 Nxd5 5. cxd5 Rxd5
>                9->   0.80   1.22   1. Nb5 Rd7 2. Ra8 Nxa2 3. Rxa3 Nb4
>                                    4. Kf2 Nxd5 5. cxd5 Rxd5
>               10     1.10   1.18   1. Nb5 Rd7 2. Ra8 Nxa2 3. Ra6+ Kg5
>                                    4. Rxa3 Nc1 5. Rh3 h5 6. Rc3
>               10->   1.58   1.18   1. Nb5 Rd7 2. Ra8 Nxa2 3. Ra6+ Kg5
>                                    4. Rxa3 Nc1 5. Rh3 h5 6. Rc3
>               11     2.85   1.38   1. Nb5 Rd7 2. d6 Ne2+ 3. Kf2 Nd4 4.
>                                    Nxd4 exd4 5. c5 Kg5 6. Ra8 d3 7. Rxa3
>               11->   4.10   1.38   1. Nb5 Rd7 2. d6 Ne2+ 3. Kf2 Nd4 4.
>                                    Nxd4 exd4 5. c5 Kg5 6. Ra8 d3 7. Rxa3
>               12     6.41   1.36   1. Nb5 Rd7 2. d6 Nxa2 3. c5 Nb4 4.
>                                    Nxa3 e4 5. Nb5 Nc6 6. Re8 Kg5
>               12->   9.37   1.36   1. Nb5 Rd7 2. d6 Nxa2 3. c5 Nb4 4.
>                                    Nxa3 e4 5. Nb5 Nc6 6. Re8 Kg5
>               13    20.40   1.56   1. Nb5 Rd7 2. d6 Nd3 3. Rc8 e4 4. Rc7
>                                    Rd8 5. c5 e3 6. Kf1 Nc1 7. c6 Nxa2
>               13->  26.10   1.56   1. Nb5 Rd7 2. d6 Nd3 3. Rc8 e4 4. Rc7
>                                    Rd8 5. c5 e3 6. Kf1 Nc1 7. c6 Nxa2
>               14    48.10   1.49   1. Nb5 Rd7 2. d6 Nd3 3. Ra8 e4 4. Rxa3
>                                    f4 5. Rc3 Nc5 6. Kf2 e3+ 7. Ke2 Kf5
>                                    8. h4
>
>
>>
>>Note that at that time the position was tested on other programs and no program
>>could find Nb5 in 15 minutes but today chess programs are better and have no
>>problem to find Nb5
>>
>>8/r5pp/3N2k1/3PpR2/2P5/p7/n5PP/6K1 w - - 0 39 am Rxe5 bm Rf3 (I am not sure if
>>h4 is enough for a draw because of h5)
>
>
>I get Rf3 instantly here with a draw score.  Score 0.00 from the 1 second
>mark on.  Did DT play Re5?  I could see where it might miss the draw since
>it had a repetition flaw...

Yes it played Rxe5 and lost.

>                9     2.30   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>         (2)    9->   2.65   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>               10     3.00   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>         (3)   10->   5.40   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>         (2)   11     6.40   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>         (2)   11->  12.10   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>               12    14.93   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>         (2)   12->  26.11   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>               13    30.78   0.00   1. Rf3 Nc1 2. Rg3+ Kh5 3. Rh3+ Kg4
>                                    4. Rg3+ Kh5
>
>
>>
>>Deep Blue - Kristensen,B
>>r1b2rk1/ppppnppp/2n3q1/1N6/2B1P3/2P1b3/PP3PPP/RN1Q1RK1 w - - 0 1 bm fxe3
>>
>
>This one is harder (for me/crafty).  Crafty likes Nxc7 for a good while.
>I ran these on a quad 550 and after 1:44, finishing depth=12, it had not
>changed...  I might run this longer later tonite...

I agree that this is not simple
even movei that does not like knight in the corner wants to play Nxc7

Here is some analysis of movei

11 -38 11637 14297599 b5c7 d7d5 e4d5 c6e5 f2e3 e5c4 d1d4 c8h3 f1f2 b7b5 c7a8
f8a8
12 -59 20619 25755380 b5c7 d7d5 e4d5 c6e5 f2e3 e5c4 d1d4 e7f5 d4c4 f5e3 c4e2
e3f1 c7a8
12 -59 42033 52206112 b5c7 d7d5 e4d5 c6e5 f2e3 e5c4 d1d4 e7f5 d4c4 f5e3 c4e2
e3f1 c7a8


My opinion is that white position is already not good and white also did a
mistake earlier in the game.

The previous mistake was Nb5 that should lose a pawn.

[D]r1b2rk1/ppppnppp/2n3q1/2b5/2BNP3/2P1B3/PP3PPP/RN1Q1RK1 w - - 0 9

>
>
>
>>
>>
>>
>>Kristiansen,J - Deep Blue
>>1r5r/5ppk/ppppqP1p/4p1PR/P1P1P2P/1P4Q1/2P3R1/7K b - - 0 35 bm Kg8
>
>
>What does this matter?  Black is dead lost already it seems.  My score starts
>out at +1.5, goes to +2.7 within seconds...  Thru depth=11, score is +2.77 for
>g6.  g6 fails low to +3.5 at depth=12, Kg8 becomes best with a score of +2.81.
>I hardly see the difference between the two moves and it looks hopeless
>already...

I see only a pawn down for Kg8 when g6 lose the game by simple tactics.
I guess that you have +1.81 positional score because of black's positional
problems.

There are other programs that see only +1.xx for white after kg8.

Uri



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