Author: Miguel A. Ballicora
Date: 14:19:11 03/09/02
Go up one level in this thread
On March 09, 2002 at 00:12:53, Uri Blass wrote: >On March 08, 2002 at 18:46:01, Miguel A. Ballicora wrote: > >>On March 08, 2002 at 15:18:35, Uri Blass wrote: >> >>>On March 08, 2002 at 14:46:41, Miguel A. Ballicora wrote: >>> >>>>On March 08, 2002 at 12:43:05, Uri Blass wrote: >>>> >>>>>On March 08, 2002 at 12:31:14, Heiner Marxen wrote: >>>>> >>>>>>On March 08, 2002 at 09:22:58, Ed Schröder wrote: >>>>>> >>>>>>>[d]4r3/p1p1pPp1/P1P1P1P1/5K2/3p2P1/7p/3P1ppr/3R1nkq w - - id M19; >>>>>>> >>>>>>>I came across this beauty, mate in 19 moves. Rebel has no clue. >>>>>>> >>>>>>>Ed >>>>>> >>>>>>After 15 minutes (Athlon 1500+, 128 MB hash) Chest says "no mate in 12". >>>>>>With an EBF above 6 this extrapolates to 8 years for the mate in 19. >>>>>>Uhh. >>>>>>Not reachable for Chest, as is. >>>>>> >>>>>>Cheers, >>>>>>Heiner >>>>> >>>>>I am not so sure >>>>>Maybe chest is going to surprise us and find an alternative mate in 14. >>>>> >>>>>I also could not prove that there is no shorter mate then mate in 19 so I cannot >>>>>be sure that the mate in 19 that I found is really the shortest mate. >>>> >>>>There is no shorter mate than 19. It is very easy to solve but it is beautiful! >>>> >>>>Regards, >>>>Miguel >>> >>>Did you prove it? >>> >>>The only way is to prove that black can draw or force a checkmate after every >>>alternative to the original solution. >> >>You can use logic to prove too. If you do not follow the solution path, black is >>stalemated immediately or liberated, in that case black wins. >> >>Miguel > >It is not a proof. >After Rc1 only the black rook can move except d3 so I am not sure that black >wins. it is not a proof, it is just the hint of how you can get the proof. Black could win if the white rook leaves the first rank. After Rc1 (or Rb1), black plays d3. Now, The only way that white can win is to promote somehow. If the rook leaves the first rank to capture black pawns, it takes 6 moves to promote. In two moves, black is promoting with a huge advantage. So, that is not an alternative. The other chance is to capture the d3 pawn the king. At that moment, Black plays Rd8+ with a draw. The king has no place to hide (and cannot capture the rook because it is stalemate). So, the only alternative left is to take the rook now. Obviously, the only chance is to promote with a knight otherwise is an immediate draw. After d3, you can follow the path of the solution manually. The options are very few and can be checked easily. Regards, Miguel >white may have ideas of capturing the black d pawns and getting progress >with the white d pawn or promoting f7f8Q if the rook leaves the 8 rank. > >I guess that they do not work but this is not a proof. > >I also did not prove that black can get stalemate in the other alternatives and >it is possible that there is something that I missed(I did not check every >possible different line like fxe8N d3 Nd6 exd6 and it may be possible that in >some line white can play something like Rb1,Rb2 and win. > >It does not seem to be true but it is not a proof. > >Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.