Author: Christoph Fieberg
Date: 14:55:48 07/11/01
Go up one level in this thread
On July 11, 2001 at 17:36:36, leonid wrote: >On July 11, 2001 at 15:20:17, Heiner Marxen wrote: > >>On July 11, 2001 at 14:33:12, Christoph Fieberg wrote: >> >>>On July 11, 2001 at 12:22:15, Heiner Marxen wrote: >>> >>>>On July 11, 2001 at 11:45:17, Christoph Fieberg wrote: >>>> >>>>>I composed the following position: >>>>>[D]r2qk2r/8/8/qqqqqqqq/QQQQQQQQ/8/8/R2QK2R b KQkq - 0 80 >>>>> >>>>>Who can construct a game to reach it? >>>>> >>>>>In my first attempt I needed 161 moves (last move was 81.Ke1). >>> >>>161 moves was meant as half-moves! (as you could see from the notion 81.Ke1) >>>Sorry, that I did not express excatly. >> >>I see! Sorry, could have guessed that myself. >>To avoid this sort of confusion, in the context of computer chess half-moves >>are often called "plies". >> >>>> >>>>If the white K has moved, its castling rights KQ should be removed! >>>> >>> >>>In my game both kings had moved! Therefore no castling possible any more. >> >>Aha. In that case the same mate in 8 does follow, but the solution time >>of Chest reduces from 330.54 secs to 296.10 secs. I didn't expect the >>difference to be that large... Chest still can surprise its author :-) > > >Hi! I found this "strange" position to be very much like my "normal" one. When >you indicated that it contain mate in 8, I thought that, probably, it is more >that coincidence. > >LLchess mate solver. 600Mhz. No hash. Castling regarded as existing. > >First mate for white side found for 8 moves deep in 35 seconds. > >Obviosly mate for black side in 8 moves also existe and was found. > >Cheers, >Leonid. Hi Leonid, your position indeed inspired me to construct the above one. The main difference is that the position above is possible from a real game (within 69 moves). Did you see my comment: http://www.icdchess.com/forums/1/message.shtml?179231 ? What about my challenge? Can you reach the position with less than 69 moves? Best regards, Christoph > > > > >>>>>Who needs less moves? >>>> >>>>IIRC, Popeye can construct proof games. But more than 300 plies? >>> >>>As explained only 161 plies are necessary! Can Popeye cope with it? >> >>I have no idea, since I did not really use that feature. >>I have studied its source code for a similar job, i.e. help mates, >>which uses basically the same technique. The program calculates a good >>minimum distance between source and destination position and uses this >>to prune early. >> >>Whether this method is good enough for this problem... I just don't know. >>You could try it yourself: Popeye is sort of free (GNU copyleft IIRC). >> >>Regards, >>Heiner >> >> >>>Regards, >>>Christoph >>> >>> >>>>I cannot imagine any program to proove the shortest proof game for such >>>>a position... but then, what do I know? >>>> >>>>>Best regards, >>>>>Christoph >>>> >>>>Regards, >>>>Heiner
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