Author: Helmut Conrady
Date: 09:39:21 10/17/05
Go up one level in this thread
On October 16, 2005 at 21:14:13, Marc Bourzutschky wrote: >Almost 15 years after Lewis Stiller's discovery of a 243 move win in KRNKNN, >we now have an even deeper win requiring 290 moves, in KRRNKRR. Wins are >measured as the shortest number of moves required to either checkmate or >capture to a won subgame. The database was constructed using Yakov Konoval's >excellent program. It took a little over 4.5 days to compute on a 3.6GHz P4, >and required about 700MB of RAM. Verification took about a day. Even though >the extra pair of rooks increases the winning chances of the stronger side >compared to KRNKR, the ending appears to be a draw in general. There are 4574 >mutual zugzwangs. > >Since only a small number of 7-man endgames has been explored so far, there is >a good chance even deeper wins will be found. > >By contrast, the longest win in KRRBKRR requires "only" 138 moves. The ending >also appears to be a draw in general, but this will need further investigation. >There are 1666 mutual zugzwangs. > >So at this time, the longest win in endgames that are generally drawn is 290 >moves in KRRNKRR, followed by 243 moves in KRNKNN. For endings that are won in >general the longest win takes 226 moves in KRBNKRB with same-colored bishops, >followed closely by 224 moves in KBNNNKQ and 223 moves in KRBKNN. Wooooooooooooooooooooooooooooooooooow! Congratulations to you and Yakov. I didn`t expect that Stiller`s record from 1996(?) will be broken in one of the very first 7-man you created! Helmut
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