Author: Robert Hyatt
Date: 17:46:50 03/13/00
Go up one level in this thread
On March 13, 2000 at 15:12:06, Dave Gomboc wrote: >On March 13, 2000 at 14:15:52, KarinsDad wrote: > >>On March 12, 2000 at 15:54:16, Robert Hyatt wrote: >> >>>On March 12, 2000 at 15:39:57, John Coffey wrote: >>> >>>>[D]1Q6/K7/8/3k4/8/8/8/8 w - - >>>> >>>>I had this position in a game and I wondered what the shortest route to mate >>>>is. I have seen methods by which one advances the king first and other methods >>>>where one advances the queen first. >>>> >>>>I think that Qf4 might be the best move although I can't prove it. >>>> >>>>I gave the problem to Fritz6 thinking that it would either know the answer >>>>immediately or would be able to find it quickly. After some searching it came >>>>up with mate in 31, but after playing a move or two it quickly turned into mate >>>>in 9. >>>> >>>>After searching several hours Fritz came up with Qb4 mate in 26. I don't know >>>>if that is the fastest solution since I have heard that one can mate with this >>>>in less than 20 moves. >>>> >>>>John >>> >>>Here is the right answer: >>> >>>White(1): egtb ! >>>1. Qf4! Kc5 2. Qe4 Kb5! 3. Qd4 Ka5 4. Kb7! Kb5! 5. Kc7! Ka5! 6. Kc6! >>>Ka6! 7. Qb6# >>> >>>Obviously a mate in 7. Moves with a ! after them are the _only_ move that >>>provides the best resistance (all other moves there result in a shorter >>>mate). >> >> >>So why are there ! marks after white moves? Since black is performing the >>resistance, it does not make sense that a white ! move means that it provides >>the best resistance (rather, the shortest mate at the current position). >> >>KarinsDad :) >> >>PS. I couldn't resist being a smart---. >> >>PSS. After working on our program last night for 5 hours, my partner and I >>managed to only fix 3 bugs (none of which are the reason for the major bug we >>are really trying to fix). However, the good news is that my partner previously >>put hash tables into the code behind my back. The bad news is that the main bug >>we are trying to fix may be due to the hash table (and it is not yet coded to >>simply remove hashing if desired). Sigh. >> >> >>> >>>(the above is output from Crafty). > >If there's an exclamation mark after White's move, it probably means that it's >the only _winning_ move -- that other moves draw. > >Dave ! moves are the "only" move to preserve the shortest (for the winning side) or longest (for the losing side) mate. If one move is mate in 10 and the rest are mate in 11 or more, the mate in 10 move gets a !. If one move is mated in 20 and the rest are mated in 19 or less, the mated in 20 gets a !. It really means "this is the 'only' move to play here to achieve 'optimal' results."
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