Author: Uri Blass
Date: 06:00:12 03/05/01
Go up one level in this thread
On March 05, 2001 at 00:57:48, Uri Blass wrote:
>On March 04, 2001 at 23:04:22, Bruce Moreland wrote:
>
>>On March 04, 2001 at 11:28:51, Sune Larsson wrote:
>>
>>>On March 04, 2001 at 10:50:54, Enrique Irazoqui wrote:
>>>
>>>>On March 04, 2001 at 10:28:01, Sune Larsson wrote:
>>>>
>>>>>
>>>>> [D]8/5pb1/7p/6PK/7P/Pk6/8/8 w - - 0 1
>>>>>
>>>>> Ellison, 1972
>>>>>
>>>>> No story around this one, except to show how tricky endgames with
>>>>> very few pieces can be. One mistake and you're dead...
>>>>> Here white is fighting for the draw. After 1.gxh6 he will find the
>>>>> way, to the remaining black pawn, very long...
>>>>>
>>>>> Test: White to move and draw. It might be interesting to check if your
>>>>> program can make it in a) blitz (5-10 min) b) rapidgame (30-60 min)
>>>>> c) tournamentlevel (40/2). The solution is further down.
>>>>>
>>>>> Sune
>>>>
>>>>Deep Shredder picks g6 in a fraction of a second. Deep Fritz in 11 seconds,
>>>>Gandalf 4.32h in 56, while Junior 7 beta and the Tigers don't see it in less
>>>>than 5 minutes.
>>>
>>> Hi Enrique, why, in your opinion, do the top programs differ that much
>>> in this position? Is it possible to trace down some lack of knowledge?
>>> For the Tigers I guess it can have something to do with missing TB:s,
>>> but Junior 7 beta??
>>>
>>> Sune
>>
>>An obvious possibility is null move in endings. If you have that turned on,
>>there are a lot of endings you won't solve ever.
>>
>>bruce
>
>Not for Junior7 because Junior7 is not a null mover.
>
>I also think that it is a mistake to use null move without doing zunzwnag
>detection at even reduced depth.
>
>I believe that there are also some zunzwangs in the middle game and it will be
>interesting to know the number of cases when it happens.
>
>Here is an example for a position that may be defined as a zunzwnag in the
>middle game from one of my coorrespondence games.
>
>[Event "correspondence"]
>[Site "?"]
>[Date "????.??.??"]
>[Round "?"]
>[White "Uri blass"]
>[Black "dov rozenberg"]
>[Result "1-0"]
>[ECO "C42"]
>[Annotator "Blass,U"]
>[PlyCount "79"]
>
>{134217720kB. PentiumIII} 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5
>6. Bd3 Bd6 7. O-O O-O 8. c4 c6 9. cxd5 cxd5 10. Nc3 Nxc3 11. bxc3 Bg4 12. Rb1
>Nd7 13. h3 Bxf3 14. Qxf3 Nb6 15. Bd2 (15. Bd2 {0.37/21 29045}) 15... Qc7 16.
>Rfe1 Rfe8 17. a4 (17. a4 {0.44/20 20806}) 17... Bh2+ {(part of my programs
>like this move but it was clear to me that wasting a tempo cannot be a good
>idea,Rxe1+ was better)} 18. Kh1 Bd6 19. Rec1 (19. Rec1 {0.71/21 23912}) 19...
>a5 {0.38/10 518} 20. Rb5 {0.78/22 30027} 20... Qc6 21. Rcb1 {0.91/21 19948}
>21... Bc7 {0} 22. Bf4 {0.97/22 29630} 22... Bd8 23. Be5 {0.95/20 22999} 23...
>Re6 24. Bc2 {1.10/22 25241} 24... Re7 {0} (24... f6 25. Bg3 {1.27/21 18001})
>25. Kg1 {1.05/20 22434} 25... f6 26. Bg3 {1.24/21 20791} 26... Kh8 {0} 27. Qh5
>{1.99/21 27889} 27... g6 28. Bxg6 {2.45/20 27912} 28... Nxa4 {25} 29. c4 Nc3
>30. cxd5 {3.65/20 21121} 30... Qd7 {2.28/13 2640} 31. d6 {4.11/21 21764} 31...
>Ne2+ 32. Kh1 {4.11/23 19686} 32... Nxg3+ 33. fxg3 {4.11/21 15} 33... Qxd6 34.
>Bxh7 {4.23/21 15763} 34... Rxh7 35. Qe8+ Kg7 36. Rxb7+ Bc7 37. Qxa8 Kh6 38. Rc1
>Re7 39. Qh8+ {7.27/21 19869} 39... Kg6 {0} 40. Qg8+ Kh6 and black resigned
>
>25.Kg1 put black in a small zunzwang from Junior's point of view and that this
>is the reason that Junior chose this move.
>
>Here is the position:
>
>[D]r2b2k1/1p2rppp/1nq5/pR1pB3/P2P4/2P2Q1P/2B2PP1/1R4K1 b - - 0 1
>
>
>
>It will be interesting to compare the score of this position with the score of
>the same position with black to move to see the opinion of other programs.
The position is not a zunzwang from yace point of view.
Kg1 has the threat Qf5 g6 Qf6 Qxf6 Bxf6 Re2 Bxd8 Rxd8 Bb3
This line seems to be correct and Junior can see 1.33 pawns for white at the
root position after learning from this line.
the same line can be made also without Kh1-g1 but in this case the position is
sligtly less good from computer's point of view because f2 is not protected
Uri
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