Author: John Merlino
Date: 12:37:17 01/26/01
Go up one level in this thread
On January 26, 2001 at 15:11:54, Dieter Buerssner wrote:
>On January 26, 2001 at 06:06:01, Thomas Lagershausen wrote:
>
>>In the following game played in the cadaques-tournament Fritz played a
>>wonderfull pawnsac to get a winning queenending.
>>59.b5-b6! is great.
>
>I agree.
>
>>It looks like Fritz have some special endgameknowledge about
>>the type of queenendings.I analysed the position 30 minutes with Shredder 5 and
>>Yace 0.99 but both are not able to convice me that they could win this
>>position.
>
>Hi Thomas. I looked at this with Yace, and you are right, that it will not
>move b6. But I think, there is a good reason. I believe Uri's suspision is
>totally correct, and Fritz did not look deep enough. After Rxg2 Qxg2
>Fritz shows a score of > 5, but later it gets a big fail low, to +1.4 and sees
>the loss of a pawn. When it had known this in advance, it probably would have
>never choosen b6. I believe the line is much too long, to see a forced win for a
>chess program. Probably not many chess programs would give up a pawn here.
>
>The same for Crafty. When I do a few moves in the line, the score drops
>immediately from 6.0 to 1.5.
>
>I have some extensions in Yace, that should help to see the threat of perpetual
>checks. Perhaps I am wrong, but I believe Yace sees rather fast, that in
>the b6 line a pawn is lost. You can also see this from the PV. Only many
>moves later, Yace can see, that the Q ending is won for white.
>
>I think, Yace would win this with white after b6, which gets considered,
>and fails low later. But this would be more or less pure luck.
>
>After b6 I get
>
> 5648651 31.240 -0.51 11t 1...Rxg2+ 2.Qxg2 Qe5+ 3.Qg3 Qb2+ 4.Kh1 Qc1+
> 5.Kg2 Qd2+ 6.Qf2 Qg5+ 7.Kf1 Qc1+ 8.Qe1 Qf4+
> 9.Kg2 Qxb8 10.Qc3+ Kh6 11.Qc1+ Kh5 12.Qc7 Qg8
> 13.Qe5+ Kh4 14.b7 Qa2+ 15.Kf3 {0}
>
>The dangerous pawn on b7 is seen, an the value may be too small (other programs
>usually give much higher values to PPs than Yace, however one also has to
>consider, that the material value of a pawn is smaller in Yace, than in many
>other programs), but it is still one pawn less, than for differnt choices for
>the 59th move of white.
>
>Regards,
>Dieter
Chessmaster 8000, default settings, also disagrees about b6. Here's its output:
Time Depth Score Positions Moves
0:00 5 1.88 19352 1. Qc7+ Qf7 2. b6 Re7 3. Qc3+ Kh6
4. Rd8 Qf4+ 5. Qg3
0:00 6 1.88 50103 1. Qc7+ Qf7 2. b6 Re7 3. Qc3+ Kh6
4. Rd8 Qf4+ 5. Qg3
0:03 7 3.98 357015 1. Qc7+ Kh6 2. Qf4+ Kh5 3. Qg4+
Kh6 4. Qxe2 Qd6+ 5. g3 Qxb8 6.
Qe3+ Kg7 7. b6 Qb7 8. Qe5+ Kf8
0:06 8 4.15 565935 1. Qc7+ Kh6 2. Qf4+ Kh5 3. Qg4+
Kh6 4. Qxe2 Qd6+ 5. g3 Qxb8 6.
Qe3+ g5 7. b6 Qb7 8. Qe6+ Kg7
0:16 9 4.30 1591585 1. Qc7+ Kh6 2. Qf4+ Kh5 3. Qg4+
Kh6 4. Qxe2 Qd6+ 5. Kg1 Qxb8 6.
Qe3+ Kg7 7. b6 Qb7 8. Qe5+ Kg8
9. Qe8+ Kg7
0:57 10 4.63 5550078 1. Qc7+ Kh6 2. Qf4+ Kh5 3. Qg4+
Kh6 4. Qxe2 Qd6+ 5. Kg1 Qxb8 6.
Qe3+ Kg7 7. b6 Kg8 8. Qd4 Kf7 9.
Qd5+ Ke7 10. b7
3:46 11 5.59 21528387 1. Qc7+ Kh6 2. Qf4+ Kh5 3. Qg4+
Kh6 4. Qxe2 Qd6+ 5. g3 Qxb8 6.
Qe3+ Kg7 7. b6 Kg8 8. Qb3+ Kf8
9. Qa3+ Ke8 10. Qa7 Qe5 11. Qxh7
No new PV after 15 minutes, so that's its move. I should also mention that b6 is
its EIGHTH best move (h4 is second).
jm
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.