Author: Uri Blass
Date: 00:44:57 02/04/05
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On February 04, 2005 at 03:41:01, Uri Blass wrote: >I find that there are some illegal positions in nalimov tablebases like the >following position because there is no possible last move of white. > >[D]3K4/8/8/3R4/3kR3/8/8/8 b - - 0 1 > >Note that the following position is legal(last move of white could be under >promotion to a rook) >[D]kR1K4/8/R7/8/8/8/8/8 b - - 0 1 > >I wonder if somebody cared to count the number of legal positions with 6 or less >pieces. > >A position with 4 pieces is illegal if it cannot be reached from position that >is not obviously illegal of 5 piece or less pieces so it is possible to count >the number of 4 piece positions that can be reached from positions of 5 or 4 >pieces. > >I am not sure if all of them are legal but I cannot think about an example when >a position with 4 pieces is illegal and can be reached from illegal 5 piece >position. > >note that it is different with 5 piece position and 6 piece position and here is >an example. > >[D]6k1/8/8/8/8/8/3P1P2/4B1K1 w - - 0 1 > >illegal > >can be reached from >[D]6R1/5k2/8/8/8/8/3P1P2/4B1K1 b - - 0 1 >also illegal. > >Uri In a second thought This is illegal position that can be reached from illegal 5 piece position [D]8/8/8/8/8/1k6/1P6/B1K5 w - - 0 1 Uri
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