Author: Uri Blass
Date: 21:26:38 10/03/01
On October 03, 2001 at 11:30:56, Robert Hyatt wrote: >On October 03, 2001 at 09:58:48, Uri Blass wrote: > >>On October 03, 2001 at 09:47:04, Chessfun wrote: >> >>>On October 03, 2001 at 08:58:28, Uri Blass wrote: >>> >>>>I do not understand some draw decisions >>>> >>>>For example the following position from bringer's game in the last round: >>>> >>>>[D]8/2R5/8/6K1/1k6/7p/6bP/8 b - - 0 107 >>>> >>>>The last capture was at move 96 and I am not sure if white cannot win this >>>>position >>>> >>>>If white can get the following position in the game then it seems to me that >>>>black is losing(I do not have the 5 piece tablebases of KRP vs KB and someone >>>>with these tablebases can probably say even that it is a forced mate and exactly >>>>the number of moves. >>>> >>>>Uri >>> >>>It's mate in 21, but I can't see how White can force black into this position >>>within 18 more moves. >>> >>>Sarah. >> >>I also cannot see and the original position may be a draw with exact game >>If someone decide to build the 6 piece tablebases for 4 pieces with blocked >>pawns(white pawn at h2 and black pawn at h3) we may know. >> >>Maybe it is a good idea to tell chess programs to build these tablebases during >>a game when the hardware is fast enough and it is tournament time control. >> >>It may be a very good option for correspondence games even today. >> >>Even if programs need 30 to build these tablebases it may be possible to do it >>at some tournament time control games when this kind of position is in the root >>and the program may use 30 minutes for one move but later play always from the >>tablebases. >> >>Uri > > >Did you mean 30 minutes or 30 hours? 30 hours would be very fast for a 6 >piece file. With pawns, maybe 30 days. I did not suggest to generate the full 6 piece tablebase of KRP vs KBP but only the tablebases for the case when the white pawn is at h2 and the black pawn is at h3. the number of relevant positions to investigate is bounded by 31*61*60*59 in this case 31 possibilities for the black bishop(it cannot be at h3 because there is a pawn there) 61 possibilities for the white rook after putting the bishop 60 possibilities for the white king after puting bishop and rook 59 possibilities for the black king. Positions after a capture are known by the 5 piece tablebase so we do not need to investigate them. Uri
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