Author: Robert Hyatt
Date: 09:26:17 10/05/99
Go up one level in this thread
On October 05, 1999 at 11:06:03, blass uri wrote: >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 With white to move, it reaches a tablebase draw score instantly, meaning black is zugzwanged... Although I don't see why Fritz would miss the mate. I tried it on my quad xeon and I find the mate instantly even though I have all the existing tablebase files on this box, so that null move could quickly screw up with that 'draw' score returned after a null at ply=2.
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