Author: blass uri
Date: 19:25:57 03/14/99
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On March 14, 1999 at 21:30:02, Robert Hyatt wrote: >On March 14, 1999 at 16:29:07, blass uri wrote: > >> >>On March 14, 1999 at 15:52:27, Mark Rawlings wrote: >> >>>This is really an interesting position! Is the final consensus that it was a >>>sound sacrifice? I let my programs search fairly deep with no real conclusion. >>>After 1. .. Bh3 2. gxh3 Kf5 3. Kf2 Ke4 black still has a challenge forcing >>>the win. I know some others must have been running this with faster computers, >>>tablebases, etc. Any conclusions? >>> >>>Mark >> >>I think that it is a simple win for black. >>I suggest you let your programs to play one against the other in slow time >>control after 1...Bh3 2.gxh3 Kf5 3.Kf2 Ke4. >> >>I do not think that white has a chance. >>4.Bxf6 is losing against 4...d4 and if white does not take f6 then black simply >>puts the pawns at d3 and f3. >> >>Tablebases cannot help in this position because the lines that black is winning >>are not based on tablebases(there are more than 5 pieces in the board) >> >>Uri >> > > > >the last statement is wrong. IE the advantage for probing tablebases in the >search is that the program gets to pick the path to 'enter' the tablebase. I >can show you _lots_ of positions with 12 pieces on the board where Crafty has >announced a mate in 60+ because it found a deep way to force entry into a won >tablebase position. And it has happened with 16 pieces on the board also, once >against a GM two years ago in a game/30 tournament on chess.net (Roman was the >victim, mate in 28 was the announcement). > >I get thousands of tablebase hits from the position where black plays Bh3, >so tablebases do influence this significantly. I think that in this case tablebases will not help to see mate because black has more than 5 pieces in the board in the winning lines even after many moves when the computer understand that black is winning. I think that you get thousands of tablebases hits to see draws and not to see mates in relevant lines. Tablebases may help in this position only not to calculate draw lines and help crafty to go deeper. I think that there is a simple test to see if tablebases can help in this position. If you can go deeper with tablebases in this position then tablebases help otherwise they probably do not help. Uri
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