Author: Michael Neish
Date: 06:43:40 12/17/02
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>Here is part of the analysis > >seeing negative score for Qxa4 is easy >avoiding it is less easy but movei needs only 10 plies > >9 -151 1269 2148341 e8a4 f3g5 b8f8 d5e7 g8h8 d2f4 a4c2 e1e2 c2c5 f2f1 f7f6 e7g6 >h8g8 g6f8 f6g5 >10 -213 2332 3879872 e8a4 f3g5 b8f8 d5e7 g8h8 d2f4 a4c2 e1e2 c2c5 f2f1 d6d5 g5f7 > f8f7 f4f7 c5c1 e2e1 c1c4 f1g1 c4d4 f7f2 >10 -212 3584 6142397 e8f8 >10 -199 4457 7666033 e8f8 d5b4 b7c5 f2g1 b8e8 a4a5 e8e4 e1e4 c5e4 d2d5 >10 -199 4655 8000622 e8f8 d5b4 b7c5 f2g1 b8e8 a4a5 e8e4 e1e4 c5e4 d2d5 Thanks Uri. I fear I haven't made myself clear. My program first gets a negative score for Qe8-a4 at ten ply as well, but a large fail low occurs at ply 13 when it sees that there are all sorts of checkmates looming and loss of material is inevitable. If you let your program analyse the position normally it will change from Qa4 to Qf8 after a while, but my question is if you force Qa4 so that the program cannot change its mind, at what depth will the fail low come? Alternatively you could play Qa4 first then start the search, and add one ply to the result. There is a threat of a smothered mate on H8 where the Queen moves to G8, the Rook takes it then a Knight moves to F7 with mate. This sort of pattern is easily recognisable for a human, but a computer needs a few extra ply to see it. So the question is really "if your program needs less than 13 ply to understand fully why Qa4 is bad, what extensions is it running that enables it to do so?". Thanks to everyone for your time. I hope this thread will be useful for others as well. Cheers, Mike.
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