Author: Uri Blass
Date: 01:29:01 12/26/02
Go up one level in this thread
On December 25, 2002 at 23:23:48, Drexel,Michael wrote: >[D] Q2Q2Q1/1R6/3BR3/3k3N/2RB2Q1/5R2/Q2Q2Bp/3N3K w - - 0 1 > >Problem: >White to move >If white gives check it has to be mate in one. >Find a legal position with the highest number of possible checks. > >I discovered this 5 years ago. Took me about 16 hours to find it. >I think it is possible to find a proof that it is not possible to find more: > >85 mates in one! :-) > >I must have been crazy. > >Fritz 7.0.0.8 engine crashed in Analysis mode if I increase the number of lines >to 64 (maximum). Shredder 7 not. >I have checked it under Fritz 7 GUI and Shredder7 (=Fritz8)GUI. perft 1=142 perft 2=12 perft 3=1603 perft 4=415 perft 5=53576 perft 6=45655(0.12 seconds) perft 7=5844247(movei optimized for perft 0.431 seconds)(yace 1.054 seconds)(movei normal version for today 0.491 seconds) perft 8=3651048(13.139 seconds)(yace 23.774 seconds)(movei normal version for today 13.5 seconds) perft 9=441,943,521(37.504 seconds)(yace 90.728 seconds)(movei normal version 42.271) perft 10=950,008,655(1031.73 seconds) The last number was not verified by other programs. Finally we get perft 10>perft 9 The surprising fact in these results is that perft 8/perft 7<perft 6/perft 5 and perft 4/perft 3<perft 6/perft 5. I give another challange Find the biggest number n such that perft(n)=0 and perft(n-1) >0 here is a simple example that proves that n>11 [D]k1q5/P2QQQQQ/KP6/PP6/4q3/5q2/6q1/7q w - - 0 1 perft 1=3 perft 2=4 perft 3=4 perft 4=6 perft 5=6 perft 6=8 perft 7=8 perft 8=10 perft 9=10 perft 10=10 perft 11=5 perft 12=0 It is also easy to see that n>12 by the following example [D]k1R5/P2QQQQQ/KP6/PP6/4q3/5q2/6q1/2q4q b - - 0 1 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.