Author: martin fierz
Date: 15:06:17 01/05/02
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On January 05, 2002 at 02:18:52, Scott Gasch wrote: >Hi all, > >I just watched an interesting game on ICC between my engine (monsoon) and >Steve's (Chesterx). In the game monsoon is ahead by a few pawns but ends up >losing because its king is out of position and chester is able to queen a pawn >with the help of its knight. Here's a position: > >[D]2n3k1/p4p2/2N5/P5pp/1P6/5K2/8/8 b - - 0 34 > >Monsoon loves black in this position even after a 13 ply search -- my pawn >majority code is boosting the score and it thinks between the knight and the >pawn it will be able to contain the white pawns on the queenside. I'm only a >chess amateur but it looked to me like black was in pretty good shape too. interesting position indeed. looks to me like black is in serious trouble. white threatens b5 followed by nxa7 and game over. looks like black has to possible tries, one is to bring the king with 1...Kf8 2. b5 Ke8 3. Nxa7 Nxa7 4. b6 Nc6 5. a6 and it's game over again, the other would be 1... a6 2. Nb8 Kf8 3. Nxa6 Ke7 4. b5 Kd7 5. b6 Kc6 and the king and the knight should hold the pawns. i apologize in advance for this analysis, it's just from looking at the diagram, i have nothing to analyse here, so it may be very wrong :-) > My question is this: how deep does >your engine need to search to realize the danger in position 1? Is there any >static eval rule that might help to understand these positions bettwe? Did >monsoon blunder the endgame? If so, where? so my answers to your question are: probably 1...a6 is the only move in the diagram to save the game, because it makes white waste time to eat the a6-pawn, and in this time the black king can come to help, the static eval rule you need is encoded in my brain as what i call majority mobility - it's no use having a majority by itself, as long as there is a king standing in front of it which will stop it. if you added an eval term to include two connected passers on the 6th as very dangerous you should see the b5 Nxa7 thing earlier. another simple thing to put in your eval would be to check for all passed pawns if the king is in the square - the white king can stop each black pawn, the black king cannot stop the white pawns. cheers martin
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