Author: Eugene Nalimov
Date: 16:37:47 09/18/99
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On September 18, 1999 at 17:24:16, guy haworth wrote: >OK - I think we are in agreement though perhaps my notation was not clear >enough. > >KQQKQQ, because of its symmetry and 2Qs on each side, involves less positions >than K**K** by a factor of 8 - 1,546,346,340 to be precise. Do NOT, as Robert >Hyatt said, hold your breath for this endgame. With my indexing schema KQQKQQ is smaller - 1,237,357,440 positions. Of course that's not 2 times smaller that Stiller's, but 300+Mb is not bad saving also. >KQQKQQ also involves no pawns which require the 'solver' to consider P=R, P=B >and P=N as well as P=Q for a 'full on' solution. There ARE wins to be had only >through underpromotion. That figure includes unreachable positions (both sides >in check, double check - not possible in KQQKQQ) but the Ks are apart. You are not the first person who thinks that double check by two queens is impossible. My friends in Russia (they wrote program 'Mirage') thought that way till their program blowed up during one of the games... >Some more figures from Lewis Stiller. The 1st player wins 82.81% of these >positions; 95.5% are wins in 1 or 2 moves (Q en prise or skewer). 99.3% of >these wins are in 6 moves (11 ply) or less. I guess a chess program will be >able to full-width search 11 ply even in KQQKQQ. The EG-db becomes useful only >by augmenting the search-tree-vision of the program. > >An analysis of KQP(g7)KQP(xn) where 'x' = b OR d and 'n' =6-2 (for 'd') and 7-2 >for 'b' would be useful but is harder. How one builds the simplifications P=Q, >no captures by the pawns, and 'bK doesn't move too far from square X' into a >retrograde analysis program is not clear to me. Maybe that's the next step >forward in EG-db generation; generation with heuristics and simplifying >assumptions - Wirth/Nievergelt have proposed as much. > >I have asked W/N for an electronic copy of their paper. > >Meanwhile, the GK-v-WT BBS is beginning to think that ending 'G' is at least as >good as ending 'D'; this has the wP on h7 rather than on g5. Looks worse >because the pawn is 2 further on but the battle is really only joined on the 7th >rank anyway. The 'h' file is worse for White than the 'g' file. So maybe it's >the KQP(b7)... EG-db the World Team needs rather than the one above. Ok, it looks that I'll have KQQKQQ ready real soon now. How I can give it to you? I thought that I'll FTP it to Bob's site - is it good for you? Eugene
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