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Subject: Re: CB vs. DT2 analysis of 27...c5! and resulting eval

Author: Uri Blass

Date: 11:41:09 09/10/01

Go up one level in this thread


On September 10, 2001 at 07:56:31, Uri Blass wrote:

>On September 10, 2001 at 06:37:57, Gian-Carlo Pascutto wrote:
>
>>On September 09, 2001 at 21:05:23, Dave Gomboc wrote:
>>
>>>Is this a won position for Black?  DJ6 doesn't seem to think so, but it might
>>>just be wrong...
>>
>>Cray Blitz - Deep Thought II
>>[D]4k3/7R/3p2p1/4bpB1/8/3R2PK/r6P/r7 b - - 0 1
>>
>>Analysis by Crafty 18.08:
>>
>>49...Rb1 50.Rd2 Rxd2 51.Bxd2 Rb3 52.Bg5 f4 53.Re7+ Kf8 54.Re6 f3 55.Rxg6 Kf7
>>56.Rh6 f2 57.Kg2 Rb2
>>  -+  (-2.06)   depth: 14/31   00:02:11  84431kN, tb=113
>>49...Rb1 50.Rd2 Rxd2 51.Bxd2 Rb3 52.Bg5 f4 53.Re7+ Kf8 54.Re6 f3 55.Rxg6 Rb1
>>56.Be3 Kf7 57.Rh6 Rb2
>>  -+  (-1.89)   depth: 15/35   00:02:44  105884kN, tb=245
>>49...Rb1 50.Rd2 Rxd2 51.Bxd2 Rb3 52.Bg5 f4 53.Re7+ Kf8 54.Re6 f3 55.Rxg6 Kf7
>>56.Rh6 f2 57.Kg2 Rb2 58.Be3 Kg7
>>  -+  (-2.00)   depth: 16/37   00:05:46  217826kN, tb=1256
>>49...Rb1 50.Rd2 Rxd2 51.Bxd2 Rb3 52.Bg5 f4 53.Re7+ Kf8 54.Re6 f3 55.Rxg6 Kf7
>>56.Rh6 Rb2 57.Rh4 d5 58.Rh7+ Ke6 59.Re7+ Kf5
>>  -+  (-2.14)   depth: 17/39   00:11:33  428732kN, tb=4302
>>49...Rb1 50.Rd2 Rxd2 51.Bxd2 Rb3 52.Rh4 Kf7 53.Bg5 Ke6 54.Rc4 Kd5 55.Rh4 Kc5
>>56.Ra4 Rb2 57.Be3+ Kb5 58.Ra8 Kc4 59.Rd8
>>  -+  (-2.29)   depth: 18/41   00:31:10  1133497kN, tb=15025
>>
>>I tend to prefer Crafty over Hiarcs in endgames, but I have
>>no idea whose assesement is better here. But note that Crafty
>>is already heavy in the tablebases here, and the score is
>>going up for black...
>
>Note that it seems to me as a human that white has good chances for a draw.
>White only ned to trade the pawns and to sacrifice the bishop for the passed
>pawn.
>
>>
>>Hiarcs is around -1.55 in all these positions, but doesn't
>>hit tablebases yet.
>>
>>>Back to 47.Kg1 Ra1+ 48.Kf2 R6a2+ 49.Rd2 Bf6 50.Bh6 g5
>>
>>Instead of 50. .. g5, 50. .. d5!  and I get -2.26 in
>>favor of black.
>>
>>>I suspect that 46.Re7+ Kf8 47.Rb3 Ra8 48.Rxh7 Rxa2 49.g3 is about the same.
>>
>>Hiarcs d5 with -1.9, Crafty -2.2
>>
>>>42.Bh6 Bg7 43.Bxg7 Kxg7 might just be a draw, though.  Hmm, 42...Rcxa4, I guess, then it's similar to before.
>>
>>Yes
>>
>>>I don't know, GCP, I don't think these pawn up endings deserve +2.25.  But in
>>>order for DT2 to settle on that kind of score, if it got to these variations it
>>>must have assessed them as such.
>>
>>Crafty obviously disagrees with you, as does Hiarcs in some of the positions
>>(although its score is usually more around -1.6, it drops down the lines).
>>
>>The question is of course whose assesement is more correct.
>>
>>I do think this shows that DT's assesement wasn't bogus or due to
>>a bug.
>
>This shows nothing because there are millions of other lines that you should
>consider.
>
>It is known that most of the lines that program consider are illogical lines
>and it is clear for everyone who use common sense that deeper thought could not
>get so deep (if you assume that there is a geometric average of 2 lines that it
>needed to consider in every ply then seeing 40 plies forward from the root
>position in the relevant lines is impossible at tournament time control game and
>even 30 plies is impossible and it is clear that there are a lot of position in
>the lines that you posted when the side has more than 2 alternatives).
>
>This is probably going to be my last post in this subject inspite of the fact
>that I am not going to change my mind about it.
>
>I may argue about the question if the position is a draw or a win for black but
>not about the question if deep thought could see +2 pawns because it is clear
>that you do not assume that there was something impossible for Deep thought to
>do in this discussion when I assume that there are things that are impossible.
>
>Deeper blue could not see 60 plies forward against kasparov in a line when
>almost all the moves were singular or almost singular and you try to convince me
>that Deep thought that was weaker could see more than it in a clearly more quiet
>position.
>
>I do not buy it.
>
>Uri

For the record I decided to give my Deep fritz long time to analyze the position
after Bg5 Bg7 and here are the results

Deep Fritz can see a clear advantage for white but even 18 plies search of the
position 11 ply after the position before c5 can discover only positional
things.


Cray Blitz - Deep Thought II
[D]6k1/1r4bp/r2pb1p1/2p1npB1/N7/1PP5/P1B2RPP/1R4K1 w - - 0 1

Analysis by Deep Fritz:

33.Nxc5--
  -+  (-1.81)   Depth: 1/3   00:00:00
33.Nxc5-- dxc5
  -+  (-2.37)   Depth: 1/3   00:00:00
33.b4!
  -+  (-2.19)   Depth: 1/3   00:00:00
33.b4! cxb4
  µ  (-1.37)   Depth: 1/7   00:00:00
33.c4!
  µ  (-0.91)   Depth: 1/7   00:00:00
33.c4!
  ³  (-0.34)   Depth: 1/7   00:00:00
33.c4--
  µ  (-1.00)   Depth: 2/7   00:00:00
33.c4-- Nxc4 34.bxc4
  µ  (-1.16)   Depth: 2/7   00:00:00
33.Re1!
  µ  (-1.06)   Depth: 2/7   00:00:00
33.Re1! Kf7
  ³  (-0.44)   Depth: 2/7   00:00:00
33.Re1 h6 34.Bf4
  ³  (-0.44)   Depth: 3/11   00:00:00
33.Re1 h6 34.Bf4 Kf7
  ³  (-0.53)   Depth: 4/10   00:00:00  1kN
33.Re1 c4 34.Rb1 Bd7 35.Re1 Bxa4
  ³  (-0.62)   Depth: 5/16   00:00:00  8kN
33.Re2!
  ³  (-0.59)   Depth: 5/16   00:00:00  10kN
33.Re2! h6 34.Bf4 Bc4 35.Re3
  ³  (-0.44)   Depth: 5/17   00:00:00  13kN
33.Re2 h6 34.Bf4 Bc4 35.bxc4 Rxb1+ 36.Bxb1 Rxa4
  ³  (-0.47)   Depth: 6/18   00:00:00  29kN
33.Re2 Bd7 34.Rbe1 Bb5 35.Re3 Bxa4
  ³  (-0.56)   Depth: 7/21   00:00:00  118kN
33.Re2 Bd7 34.Rbe1 Bb5 35.Re3 Bxa4 36.bxa4 Rb2 37.Bb3+ c4
  ³  (-0.59)   Depth: 8/21   00:00:00  334kN
33.Bf4!
  ³  (-0.56)   Depth: 8/25   00:00:01  836kN
33.Bf4! Bd7 34.Rd1 Bxa4 35.bxa4 c4 36.Re2 Rb2
  ³  (-0.53)   Depth: 8/25   00:00:01  882kN
33.Bf4 Bd7 34.Rd1 c4 35.Re2 Kf7 36.Bxe5 Bxe5 37.Nb2 Rxa2 38.Nxc4
  ³  (-0.62)   Depth: 9/26   00:00:02  1388kN
33.Bf4 Bd7 34.Re1 Ng4 35.Rf3 Bxa4 36.bxa4 d5 37.Bb3 c4 38.Bc2
  ³  (-0.66)   Depth: 10/26   00:00:04  2992kN
33.h3!
  ³  (-0.62)   Depth: 10/28   00:00:08  5164kN
33.h3 Bd7 34.Rd1 c4 35.Be3 Bxa4 36.bxa4 Nf7 37.Bd4 Bxd4 38.Rxd4 Ne5
  ³  (-0.69)   Depth: 11/29   00:00:15  9984kN
33.h3 Bd7 34.Rd1 Bxa4 35.bxa4 c4 36.Re2 Nd7 37.Be7 Bxc3 38.Bxd6 Nb6
  ³  (-0.66)   Depth: 12/32   00:00:41  27331kN
33.h3 Bd7 34.Rd1 c4 35.Be3 Bxa4 36.bxa4 Rb2 37.Be4 Rxf2 38.Bd5+ Nf7
  µ  (-0.72)   Depth: 13/34   00:01:44  70231kN
33.h3 Bd7 34.Rff1 h6 35.Bf4 c4 36.Be3 Bxa4 37.bxa4 Re7 38.Rfd1
  ³  (-0.69)   Depth: 14/35   00:05:09  208826kN
33.h3 Bd7 34.Rff1 h6 35.Bf4 c4 36.Be3 Bxa4 37.bxa4 Re7 38.Bd4 Nd7
  µ  (-0.75)   Depth: 15/36   00:10:05  413349kN
33.h3 Bd7 34.Rff1 h6 35.Bf4 c4 36.Be3 Bxa4 37.bxa4 Re7 38.Bd4
  µ  (-0.75)   Depth: 16/41   00:54:31  2251192kN
33.h3 Bd7 34.Rff1 h6 35.Bf4 c4 36.Be3 Nf7 37.g4 Ng5
  µ  (-0.78)   Depth: 17/41   02:06:58  5281997kN
33.h3 Bd7 34.Rff1 Bc6 35.Bf4 c4 36.Rfd1 Nd3 37.Bxd3 cxd3 38.Rbc1 Bxa4
  µ  (-0.81)   Depth: 18/44   05:08:30  12922408kN

(Blass, Tel-aviv 10.09.2001)

Uri



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