Author: Stuart Cracraft
Date: 18:25:00 01/13/98
Go up one level in this thread
Okay -- then how much strength, if any, is square-of-the-pawn giving to the latest version of your program? When you drop this feature from the program, what does the rating fall/rise to? --Stuart On January 13, 1998 at 14:30:40, Robert Hyatt wrote: >On January 13, 1998 at 12:57:43, Stuart Cracraft wrote: > >>Years ago I remember reading something where Dan and Kathe Spracklen >>(remember them?) said that the addition of the square-of-the-pawn >>rule-of-thumb to their program increased is strength significantly. >>(I think they said a whole USCF class!) > >It wasn't Dan and Kathe, it was me. This was something I added to >"blitz" around 1970 or so. Back then, it was searching 4-5 plies >max, and had a USCF rating of around 1400, playing in local tournaments. >But it kept getting hoodwinked in endings where the opponent would offer >something to decoy the king away, and then the pawn could scamper in >before the king could catch it. It was winning middlegames, but losing >endgames. Remember too, that this was in the days of 4-5 plies of >selective search, with *no* extensions and not even a real quiescence >search. So this was a critical issue. > >When I put this in, its overall rating climbed to 1600, and stuck there >until I "went exhaustive" in 1977 when its rating jumped to 1800+, and >then when I "went Cray" in 1980 we went to 2200+. (All official USCF >rating numbers, not TPR or something else). > > >> >>Anyway, now that I have passed pawns stored in my pawn transposition >>table, it would be simple to use them in some calculation to get a >>square-of-the-pawn assessment. >> >>How have you implemented square-of-the-pawn? Are there any strange >>implementation issues or things to watch for? What kind of strength >>improvement did your program get and how did you determine this >>strength improvement. >> >>Thanks ahead! >> >>Stuart > >The issue is only "can the king catch the pawn?" If the answer is no, >score+=queen-pawn, if the answer is yes, then there's no bonus. You >still >need a search, because it is possible to have two passers, neither of >which >can outrun the king, but neither of which can be captured either because >capturing one takes you out of the square of the other...
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