Author: Scott Gasch
Date: 14:23:03 01/19/01
Hi all, Here's a pretty simple test position. This comes from the WAC suite... my engine does fairly well on this suite as a whole but seems blind to this solution. [D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - The solution is Rxb2 -- black's connected passers are unstoppable after the recapture. My program refuses to find this solution... even at 9 ply it misses it. The strange thing is that from the other side after Rxb2 it sees that white is toast very quickly... score dropping to -500 or so after about 1 second. My question is, of course, how this move is missed. I've tried kicking up the value of connected passers and passed pawns in general. I've tried adding a special rule to eval about connected passers on the 7th, on move, with control of a queening square. I've tried cutting back my futility margin in qsearch and always extending a full ply for checks (It usually extends only 3/4 ply for checks after the iteration depth). And still it does not find Rxb2. Even stranger is if I run a static eval with the two connected passers rolling towards the queening square after the rook exchange the eval puts black ahead! I can't seem to figure this out... either my pruning is too aggressive or there is some other bug in the engine...? I hope someone out there can give me a little advice. Thanks! Scott
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