Author: Bruce Moreland
Date: 22:06:19 06/23/98
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On June 24, 1998 at 00:11:20, Don Dailey wrote: >Some pieces of knowledge I accept on faith. An example of this is >the minor piece vs king rule, always a draw. I would not dream >of leaving this out of the program, and yet years ago when I >implemented it I tested the hell out of it and found no measurable >improvement to the program. It kicked in once in a great while, >but even those very few times, it did not change the results, >the game was a draw anyway! I guarantee you that if I left it >out I would be kicking myself sooner or later when it bit me. >In the program involved, I took a 1 or 2 percent hit for having >this rule but the implemenation make other rules possible. The >tiny slowdown offset the tiny improvement it made to the program >and of course I kept the rule. My feeling is that I see this one enough that it matters. In particular I have had a lot of cases where mine would be up a single bishop against two pawns, and happily display +1. Did it happen in 5% of my games? No. But this kind of stuff happened often enough that I got tired of seeing it, and since against the humans I am always playing down, I lose like 14 points for the cases I draw, and by no means did I draw all of these. It might matter if your opponent is steering things this way, or is capable of steering things this way. Humans will steer you into locked pawns and bleed you with draws, computers won't necessarily do this. They'll also go for opposite bishop endings. I think that computers will do this now, so perhaps you'll see this more often against computers than you used to. You'll also get some KRB vs KR. I get this a lot, too, or so I feel. If I looked it up though, perhaps it would amount to 1%. The other derived case is KRB vs KRP, which I score as +2 and draw every time, of course, because I refuse to even win the pawn until I'm forced to. I see this now and again as well, it is always painful. I had a computer at the 1996 WMCC take a draw against my computer rather than sacrificing its knight for two pawns, resulting in a KRN vs KRPP ending that it could not have lost but may have won. Mine would do the same thing, that's why we didn't see this happen, mine wasn't trying to avoid the situation. Against a strong human, who knows. Another great example is bishop and wrong rook pawn. This comes up a lot. In my program I understand the case where I have a bishop and some number of wrong rook pawns, and the enemy king is in the right corner. But I don't understand the case where I have the bishop and some number of wrong rook pawns, and the opponent has a pawn or two. Guess what, Crafty does. So I get steered into this occasionally, more than once, I am sure. I just sit there refusing to take the pawns, because that, of course, is a draw. It's like when Crafty knew not to play Bxh2 and get its bishop trapped ala Fischer-Spassky 1972, and mine didn't. It only nailed me with this a few times, but that was enough. Maybe none of these has a big effect upon rating, but enough of them added together matter, I think, at least against some set of opponents. This is just a feeling. If you sit around playing 1700's all day long, this will never come up, you'll win 95% of the games on straight tactics, and those you lose or draw will be impossible to save, but against an opponent with similar capabilities, you'll see more of this, I think, especially when you catch some cases and they catch some other cases. bruce
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