Author: guy haworth
Date: 14:24:16 09/18/99
Go up one level in this thread
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. 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. 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.
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