Author: Kim Roper Jensen
Date: 19:47:39 09/06/03
Go up one level in this thread
On September 06, 2003 at 22:22:55, Dieter Buerssner wrote:
>On September 06, 2003 at 21:58:14, Kim Roper Jensen wrote:
>
>>Position from the game Larsen - Kavalek Montreal Tournament of Stars
>>
>>[D]1k6/8/B3K1P1/5P2/1pRr2Nn/2b5/8/8 b - -
>>
>>Only move here for black is Nxf5 and get both white pawns and it should be a
>>draw - according to the notes by Whiteley (its taken from the tournament book,
>>by Tal, Chepizhny & Roshal)
>>
>>Shredder 6 Paderborn Classical finds Nxf5 fast, but no drawscore after a long
>>time ... this on 2Ghz AMD with 256MB hashtable but very limited
>>endgametablebases
>
>Yace needs much longer than Shredder, to find Nxf5, but it shows a somewhat
>better score:
>
> 13182076 30.090 -3.07 10. 1...Rd1 2.Ne5 Re1 3.Rxc3 bxc3 4.g7 Rg1 5.Ng6
> Re1+ 6.Kd7 Rd1+ 7.Ke8 Re1+ 8.Kf7 c2 9.g8=Q+ Ka7
> 10.Qc8 {-851}
> 18509925 38.821 -3.25 11t 1...Rd1 2.Ne5 Re1 3.Rxc3 bxc3 4.g7 Rg1 5.Ng6
> Re1+ 6.Kf7 Nxf5 7.g8=Q+ Ka7 8.Qd8 Kxa6 {-421}
> 25301247 56.569 -3.24 11t+ 1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8
> Rg5 6.Rc8+ Ka7 7.Rxc3 bxc3 8.Bc8 {-190}
> 27300699 1:00.2 -2.67 11++ 1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8
> Rg5 6.Rc8+ Ka7 7.Rxc3 bxc3 8.Bc8 {-190}
> 28541573 1:02.8 -1.67 11++ 1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8
> Rg5 6.Rc8+ Ka7 7.Rxc3 bxc3 8.Bc8
> 29155992 1:03.8 -1.66 11t 1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7H Rf5+H
> 5.Kg8H Rg5H 6.Kh7H Rh5+H 7.Nh6H Bd2H 8.Rc8+H
> Ka7H 9.Rc4H Kxa6H 10.Rxb4H {-70}
> 30881556 1:07.0 -1.66 11. 1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8
> Rg5 6.Kh7 Rh5+ 7.Nh6 Bd2 8.Rc8+ Ka7 9.Rc4 Kxa6
> 10.Rxb4 {-70}
> 42662815 1:33.0 -1.26 12++ 1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8
> Rg5 6.Kh7 Rh5+ 7.Nh6 Bd2 8.Rd4 Rxh6+ 9.Kg7 {0}
> 48237358 1:42.9 -0.91 12t 1...Nxf5 2.Kxf5 Rd5+ 3.Kf4 Rd6 4.g7 Bxg7
> 5.Rxb4+ Ka7 6.Rb7+ Kxa6 7.Rxg7 Kb6 8.Ne5 Kc5
> 9.Kf5 Kd4 10.Re7 {-340}
> 53235180 1:53.3 -0.91 12. 1...Nxf5 2.Kxf5 Rd5+ 3.Kf4 Rd6 4.g7 Bxg7
> 5.Rxb4+ Ka7 6.Rb7+ Kxa6 7.Rxg7 Kb6 8.Ne5 Kc5
> 9.Kf5 Kd4 10.Re7 {-340}
>
>The -0.9 can be interpreted as: Actually I am quite confident, that this is a
>drawish position, even if I a less material.
>
>You could ask: Why then not give a draw score, when quite confident? Because it
>will yied in problems! Crafty, for example, will evaluate KR + minor piece vs KR
>as 0.01 (it is much more confident of the draw). But by this, it can (and does)
>easily lose drawn games. Now, all defender moves look exactly the same, and it
>is easy to do some bad moves sooner or later. Then a draw will go to a loss.
>Those close to 0.0 scores cannot differntiate between - uff my K is already at
>the edge, and the opponent has mating possibilities, and between - no problem.
>Of course, in the actual scenario I mentioned (only 5 pieces) TBs will help. But
>when you add a pawn to the inferior side, the will not help much anymore. For my
>engine, it seemed best, to give such very probably drawish positions somewhat
>higher scores, giving the engine the possibility to differntiate between really
>critical positions, and other ones, that are not that tough.
>
>Regards,
>Dieter
One funny thing in the given line by YACE - it uses the bishop to get the
g-pawn, i think it's more 'safe' to use the rook and keep the bishop protected
.... why is that ?
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