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Up Topic Rybka Support & Discussion / Rybka Discussion / Sajasrabudjie 1977 artistic study
- - By Debaser (***) Date 2007-12-15 00:48
Is any engine able to solve this or is there an error? This is supposed to be a positional draw. Kullberg, can you try the last Rybka build? ;)

N5b1/6pk/1b6/6P1/2Q2p1p/1K6/6P1/8 w - - 0 1
Parent - By BB (****) Date 2007-12-15 01:22
The analysis here claims a draw after 1. g6 Kh8 2. Nxb6 Bxc4 3. Kxc4 f3 4. gxf3 h3 5. Nd5 h2 6. Ne7 h1Q 7. Kd5 Qxf3+ 8. Ke6. Black's moves are essentially forced . Once the white king can reach e6, it doesn't matter if f3 falls.
Parent - - By Gaмßito (****) Date 2007-12-15 07:59 Edited 2007-12-15 08:09
I think that there are no program that can understand this position without due knowledge.   

Black is completely unable to make some progress. Black King cannot leave from h8. The Queen is totally useless and cannot take the pawn on g6 while the knight be on e7. And this Knight would not move from there anymore.

You clearly can see that programs cannot understand these simple things. Look the resultant position. Any little child or any 1200 elo chess player can understand perfectly that black cannot make any progress and that it is a clear draw.
     
7k/4N1p1/4K1P1/8/8/5q2/8/8 b - - 0 8


Regards,
Gambito.
Parent - - By Debaser (***) Date 2007-12-15 09:59
Yes, BB and Gambito, that is the solution and the explanation ;)

The original by Sajasrabudjie is this: 1.g6+! Kh8 2.Nxb6 Bxc4 3.Kxc4 f3! 4.gxf3 h3 5.Nc8 h2 6.Ne7 h1Q 7.Kd5 Qxf3+ 8.Ke6! (8.Kd6? Qh3 9.Kc7 Qd3!) 8...Qg4+ 9.Kf7 draw

I thought that this was interesting because chess engines seem not to be able to give a draw evaluation (0.00) when there is a material imbalance like this K vs Q, even though the queen can make no progress.

As Vas an Larry are working on endgames, perhaps adding this knowledge is a goodidea.
Parent - - By Lukas Cimiotti (Bronze) Date 2007-12-15 15:04
To get a draw eval you need to to have KQPKNP tablebases. I havn't got them, so none of my engines sees the draw.

Regards,
Lukas
Parent - By Debaser (***) Date 2007-12-15 15:26
Thanks. The last Rybka build is not better here then? An aspect to improve.

And no way for tablebases, then what be want the engine for? ;)
Parent - By BB (****) Date 2007-12-15 17:50
To get a draw eval you need to to have KQPKNP tablebases.

It might not be quite that simple, as Black need not play Qxf3 on move 7, and so you might need KQP vs KNPP tablebases (or KQ vs KNP + blocked pawn pair, which could be counted as six pieces).
Parent - - By Vasik Rajlich (Silver) Date 2007-12-16 16:38
This type of position is quite difficult for Rybka. We have some ideas, but probably not in time for Rybka 3.

Vas
Parent - - By Banned for Life (Gold) Date 2007-12-16 17:18
It's not common, but not rare either, to see this kind of situation which revolves around the concept of the queen not being able to mate alone when the opposing king is not further constrained.

Probably a more important concept (also used in this example) for the player seeking the draw is generally to maintain the status quo, rather than try to make progress. This is a more common goal for the side that is behind and would probably be worth an Elo or two.

Alan
Parent - By Vasik Rajlich (Silver) Date 2007-12-20 13:13
Generally, better but drawn positions should tend toward zero with deeper search, while winning positions should tend toward higher and higher scores with deeper search.

It's tricky to exploit this, though - there are problems with handling transpositions.

Vas
Parent - By Lukas Cimiotti (Bronze) Date 2007-12-15 10:49
Atm i can only look at it using Fritz 9, as i am at work.
Fritz 9 gives this analysis:

Neue Partie - Fritz 9,
N5b1/6pk/1b6/6P1/2Q2p1p/1K6/6P1/8 w - - 0 1


Analysis by Fritz 9:

1.g6+--
  +-  (2.16)   Tiefe: 7/11   00:00:00  4kN
1.g6+ Kh8 2.Sxb6 Lxc4+ 3.Kxc4
  +-  (2.02)   Tiefe: 7/11   00:00:00  4kN
1.g6+!
  +-  (2.30)   Tiefe: 8/13   00:00:00  6kN
1.g6+--
  +-  (2.02)   Tiefe: 9/16   00:00:00  13kN
1.g6+ Kh8 2.Sxb6 Lxc4+ 3.Sxc4 f3 4.Se3 fxg2 5.Sxg2 h3 6.Sf4 h2
  ±  (1.30)   Tiefe: 9/26   00:00:00  25kN
1.Dxg8+!
  +-  (1.49)   Tiefe: 9/26   00:00:00  26kN
1.Dxg8+!
  +-  (1.81)   Tiefe: 9/26   00:00:00  26kN
1.Dxg8+!
  +-  (1.81)   Tiefe: 9/26   00:00:00  26kN
1.Dxg8+--
  +-  (1.53)   Tiefe: 10/21   00:00:00  50kN
1.Dxg8+ Kxg8 2.Sxb6 f3 3.gxf3 h3 4.Sd5 h2 5.Kc4 h1D 6.f4 De4+ 7.Kc5 Kf7 8.Kc6 Ke6
  -+  (-4.50)   Tiefe: 10/29   00:00:00  123kN
1.Kc3!
  -+  (-4.50)   Tiefe: 10/29   00:00:00  165kN
1.Kc3!
  -+  (-4.34)   Tiefe: 10/29   00:00:00  167kN
1.Kc3!
  -+  (-4.02)   Tiefe: 10/29   00:00:00  170kN
1.Kc3!
  -+  (-3.40)   Tiefe: 10/29   00:00:00  173kN
1.Kc3 La5+ 2.Kd4 Lxc4 3.Kxc4 Kg6 4.Kd3 Kxg5 5.Ke2 Kg4 6.Kf2
  -+  (-2.77)   Tiefe: 10/29   00:00:00  245kN
1.Kb4!
  -+  (-2.77)   Tiefe: 10/29   00:00:00  253kN
1.Kb4!
  -+  (-2.61)   Tiefe: 10/29   00:00:00  259kN
1.Kb4 La5+ 2.Kxa5 Lxc4
  -+  (-2.59)   Tiefe: 10/29   00:00:00  279kN
1.Kc2!
  -+  (-2.59)   Tiefe: 10/29   00:00:00  294kN
1.Kc2!
  -+  (-2.43)   Tiefe: 10/29   00:00:00  300kN
1.Kc2 Lxc4 2.Sxb6 Le6 3.Sd5 Lxd5
  -+  (-2.43)   Tiefe: 10/29   00:00:00  311kN
1.Sxb6!
  -+  (-2.42)   Tiefe: 10/29   00:00:00  340kN
1.Sxb6!
  -+  (-2.26)   Tiefe: 10/29   00:00:00  340kN
1.Sxb6!
  -+  (-1.95)   Tiefe: 10/29   00:00:00  342kN
1.Sxb6!
  µ  (-1.32)   Tiefe: 10/29   00:00:00  343kN
1.Sxb6 Lxc4+ 2.Sxc4 Kg6 3.Se5+ Kxg5 4.Kc4 h3 5.gxh3 Kh4 6.Sg6+ Kxh3 7.Sxf4+ Kg4
  =  (0.16)   Tiefe: 10/29   00:00:00  408kN
1.g6+!
  ²  (0.58)   Tiefe: 10/29   00:00:00  412kN
1.g6+!
  +-  (1.65)   Tiefe: 10/29   00:00:00  413kN
1.g6+!
  +-  (1.65)   Tiefe: 10/29   00:00:00  413kN
1.g6+!
  +-  (1.65)   Tiefe: 10/29   00:00:00  413kN
1.g6+ Kh8 2.Sxb6 Lxc4+ 3.Sxc4 f3 4.gxf3 h3
  +-  (2.20)   Tiefe: 10/29   00:00:00  420kN
1.g6+--
  +-  (1.92)   Tiefe: 11/18   00:00:00  435kN
1.g6+ Kh8 2.Df7 Lxf7+ 3.gxf7 Lc5 4.Sb6 h3 5.gxh3 f3 6.Sd5 f2 7.Se3
  =  (-0.20)   Tiefe: 11/33   00:00:00  778kN
1.g6+ Kh8 2.Df7 Lxf7+ 3.gxf7 Lc5 4.Sb6 h3 5.gxh3 f3 6.Sd5
  =  (-0.20)   Tiefe: 12/29   00:00:00  900kN
1.g6+ Kh8 2.Df7 Lxf7+ 3.gxf7 Lc5 4.Sb6 h3 5.Sd7 hxg2 6.Sxc5 g1D 7.f8D+ Kh7 8.Df5+ Kh8 9.Dh5+ Kg8 10.De8+ Kh7 11.Dh5+
  =  (0.02)   Tiefe: 13/31   00:00:00  1133kN
1.g6+ Kh8 2.Df7 Lc5 3.Sc7 Lxf7+ 4.gxf7 h3 5.Se6
  =  (0.02)   Tiefe: 14/31   00:00:00  1743kN
1.g6+ Kh8 2.Df7 Lc5 3.Sc7 Lxf7+ 4.gxf7 h3 5.Se6
  =  (0.02)   Tiefe: 15/34   00:00:01  2588kN
1.g6+ Kh8 2.Df7 Lc5 3.Sc7 Lxf7+ 4.gxf7 h3 5.Se6 hxg2 6.Sxc5 g1D 7.f8D+ Kh7 8.Df5+ Kh8 9.Dh5+ Kg8 10.Dd5+
  =  (0.02)   Tiefe: 16/36   00:00:01  3510kN
1.g6+ Kh8 2.Df7 Lc5 3.Sc7 Lxf7+ 4.gxf7 h3 5.Se6 hxg2 6.Sxc5 g1D 7.f8D+ Kh7 8.Df5+ Kg8 9.Dd5+ Kh7 10.Dh5+ Kg8 11.Dd5+
  =  (0.02)   Tiefe: 17/36   00:00:03  6387kN
1.g6+--
  ³  (-0.27)   Tiefe: 18/41   00:00:06  11389kN
1.g6+ Kh8 2.Df7
  ³  (-0.27)   Tiefe: 18/47   00:00:13  25303kN
1.g6+--
  ³  (-0.55)   Tiefe: 19/41   00:00:20  37891kN
1.g6+ Kh8 2.Df7 Lc5 3.Kc4 Lxf7+ 4.gxf7 Le7 5.Sb6 g5 6.Kd5 g4 7.Ke5 f3 8.gxf3 gxf3 9.Sd5 Lc5 10.Kf6 f2 11.Se3
  µ  (-0.95)   Tiefe: 19/43   00:00:28  52871kN
1.g6+--
  µ  (-1.23)   Tiefe: 20/40   00:00:42  80125kN
1.g6+ Kh8 2.Df7 Lc5 3.Kc4 La3 4.Kb3 Le7 5.Sc7 Lxf7+ 6.gxf7 f3 7.Sd5 Ld6 8.Sf4
  -+  (-4.61)   Tiefe: 20/49   00:01:02  118958kN
1.g6+!
  -+  (-4.33)   Tiefe: 21/57   00:02:05  241280kN
1.g6+ Kh8 2.Sxb6 Lxc4+ 3.Kxc4 f3 4.gxf3 h3 5.Sd7 h2 6.Kd5 h1D 7.Se5 Kg8 8.Ke6 Kf8 9.Sd7+ Ke8
  -+  (-4.23)   Tiefe: 22/45   00:02:22  274647kN
1.g6+--
  -+  (-4.52)   Tiefe: 23/56   00:02:58  347944kN
1.g6+ Kh8 2.Sxb6
  -+  (-4.52)   Tiefe: 23/56   00:03:06  364763kN

(,  15.12.2007)

I'll look at it later today using Rybka.

Regards,
Lukas
Up Topic Rybka Support & Discussion / Rybka Discussion / Sajasrabudjie 1977 artistic study

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