Author: blass uri
Date: 08:06:03 10/05/99
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On October 05, 1999 at 10:51:29, Robert Hyatt wrote: <snipped> >On October 05, 1999 at 04:14:13, blass uri wrote: > >>On October 04, 1999 at 22:37:48, Robert Hyatt wrote: >> >>>On October 04, 1999 at 20:33:35, blass uri wrote: >>>>The relevant position is: >>>> >>>>7k/4K2p/7P/3p4/8/4Q3/1q6/8 w - - 0 1 >>>> >>>>The first evaluation above 0 of Fritz5 is +5.16 pawns for white >>>>I do not believe that it can be explained by positional compensation. >>>> >>>>If it is because of a bug then Fritz3 and Fritz4 have the same bug(I do not know >>>>if Fritz5.32 shows similiar behaviour) >>>> >>>>Uri >>> >>> >>>are you sure this is the position? This seems to be a mate in 8 according >>>to my PII/300 notebook (crafty): >>> >>> 9 4.89 0.48 1. Ke6 Qa1 2. Kd7 Qa4+ 3. Kd6 Qb4+ >>> 4. Kxd5 Qb7+ 5. Kc4 Qa6+ 6. Kb4 Qd6+ >>> 7. Kb5 Qd5+ 8. Kb4 <HT> >>> 9-> 7.46 0.48 1. Ke6 Qa1 2. Kd7 Qa4+ 3. Kd6 Qb4+ >>> 4. Kxd5 Qb7+ 5. Kc4 Qa6+ 6. Kb4 Qd6+ >>> 7. Kb5 Qd5+ 8. Kb4 <HT> >>> 10 8.27 ++ 1. Ke6!! >>> 10 12.34 Mat08 1. Ke6 Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. >>> Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. >>> Qe5+ <HT> >>> 10-> 18.59 Mat08 1. Ke6 Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. >>> Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. >>> Qe5+ Qg7+ 8. Qxg7# <HT> >>> 11 23.23 Mat08 1. Ke6 Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. >>> Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. >>> Qe5+ Qg7+ 8. Qxg7# >>> 11-> 36.33 Mat08 1. Ke6 Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. >>> Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. >>> Qe5+ Qg7+ 8. Qxg7# >>> 12 50.03 Mat08 1. Ke6 Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. >>> Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. >>> Qe5+ Qg7+ 8. Qxg7# >> >>I am sure that it is the position and I believe that the reason that Fritz >>cannot see the mate is that it is a null move problem for Fritz. >>1.Ke6 threats nothing. >> >>Try the position after Ke6 with white to move. >> >>Uri > > >I get this: > > 9 5.01 -Mat07 1. ... Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. > Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. > Qe5+ Qg7+ 8. Qxg7# <HT> > 9-> 6.13 -Mat07 1. ... Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. > Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. > Qe5+ Qg7+ 8. Qxg7# <HT> > 10 11.37 -Mat07 1. ... Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. > Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. > Qe5+ Qg7+ 8. Qxg7# > 10-> 11.76 -Mat07 1. ... Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. > Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. > Qe5+ Qg7+ 8. Qxg7# > 11 24.97 -Mat07 1. ... Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. > Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. > Qe5+ Qg7+ 8. Qxg7# > 11-> 25.92 -Mat07 1. ... Qa1 2. Qb6 Qe1+ 3. Kd7 Kg8 4. > Qf6 Qg3 5. Qe6+ Kh8 6. Qe8+ Qg8 7. > Qe5+ Qg7+ 8. Qxg7# > >although it is certainly possible that small differences in the two programs >can cause interesting null-move behavior... Fritz can also see mate against itsealf after Ke6 but the point is that ke6 threats nothing so Fritz cannot see the mate before Ke6. You can prove it by analyzing the position after Ke6 with *white* to move. Uri
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