Author: Dave Gomboc
Date: 12:28:56 05/15/99
Go up one level in this thread
On May 15, 1999 at 10:20:48, KarinsDad wrote: >Well, got some sleep. Figured out that I was wrong. > >The 168 bit maximum (175 bit maxium with 50 move rule) is not really the >maximum. > >For example, white could have a pawn on f3, g4, and h4. Black could have a pawn >on f4, g5, and h5. > >White could play hg. Black could then unopposed promote his h pawn with h4. >White could now unopposed promote both of his g pawns. So, the worse case >scenario is 12 promotions (no pawns left) and every original piece still on the >board. All pieces would have to be on the 2nd to 7th rows and so we have gained >2 bits per promotion or 24 bits, 3 whole bytes. A nightmare position to be sure. > >And unlike the position I set up here, a lot of the pawn promotions in a scheme >of 12 promotions would not be unopposed. > >Now since we gain at most 2 bits per promotion, I doubt that there has every >been such a situation where EVERY other piece is still on the board and pawns >were in a configuration anywhere on the board such as the one I discribed >without the pawn promotions being stopped by the other pieces (or pawns). > >So, this is fantasy positions. However, a purist WILL say, "Hey, you screwed up, >I can set up a LEGAL position that your format will not support" (although not >one that would ever show up in a game). However, I'm not sure it is worth it to >worry about it. > >Opinions? > >KarinsDad :) > >PS. I also figured out something else important to this discussion, but I forgot >it when I fell asleep. I hate when that happens. There was a real game in a Portugese Junior championship several years ago where the final position was White: Ke8, Qd8, Ra8,h8, Bc8,f8, Nb8,g8 Black: Ke1, Qd1, Ra1,h1, Bc1,f1, Nb1,g1 (the two contestants agreed to a draw here. :-) This game was published in En Passant, though I don't recall the exact issue. Obviously it was arranged in advance, but it was still a real game. I am not sure if they did it just to be funny or also because there was a "minimum moves before draw" rule... it took them about 61 moves. So anyway, yes, please allow every legal position. This is also why I would prefer to include the adjustment for the 50-move rule. (100-ply rule! Keep that in mind!) It would be better to have something that you can use for lots of stuff, not just a particular application (opening book). Maybe a specialization here is worth a bit or two, but I think that hardly justifies it overall because the lost information may be of some slight important for some endings that are reached by opening theory. You might consider if it is worth supporting chess variants that do not introduce extra pieces as well. !? BTW, if you keep a notepad and pencil/pen by your bed, then you can scribble down ideas even when you are on the verge of falling asleep. :-) Dave
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