Author: Robert Hyatt
Date: 14:10:39 10/16/01
Go up one level in this thread
On October 16, 2001 at 16:39:07, Miguel A. Ballicora wrote: >On October 16, 2001 at 16:02:42, Uri Blass wrote: > >>On October 16, 2001 at 14:24:00, Robert Hyatt wrote: >> >>>On October 16, 2001 at 11:13:38, John Merlino wrote: >>> >>>>On October 16, 2001 at 07:58:15, Steffen Jakob wrote: >>>> >>>>>Hi, >>>>> >>>>>this is a position from a blitz game Hossa - Sjeng: >>>>> >>>>>[D]7k/4QP2/7p/6rP/8/1K6/6r1/8 b >>>>> >>>>>For a human it's obvious that this is a draw. Hossa was rather clueless and >>>>>thought that white was winning. Are there any engines which show a draw value at >>>>>once (without significant search depth)? >>>>> >>>>>Greetings, >>>>>Steffen. >>>> >>>>Chessmaster 8000 sees the draw in less than a second: >>>> >>>>Time Depth Score Positions Moves >>>>0:00 1/3 1.18 7319 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 >>>>0:00 2/4 0.95 23824 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 >>>>0:00 3/5 0.00 45109 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 R1g2+ 13. Ke3 >>>>0:01 4/6 0.00 110883 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 R1g2+ 13. Ke3 >>>>0:02 5/7 0.00 246089 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 R1g2+ 13. Ke3 >>>>0:04 6/8 0.00 498686 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 R1g2+ 13. Ke3 >>>>0:08 7/9 0.00 1039196 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 R1g2+ 13. Ke3 >>>>0:16 8/10 0.00 2092486 1...R2g3+ 2. Kc2 Rg2+ 3. Kd3 R2g3+ >>>> 4. Kc4 R3g4+ 5. Kc3 Rg3+ 6. Kb2 >>>> Rg2+ 7. Kc1 Rg1+ 8. Kd2 R1g2+ 9. >>>> Ke3 R2g3+ 10. Ke2 Rg2+ 11. Kf1 >>>> Rg1+ 12. Kf2 R1g2+ 13. Ke3 >>>> >>>>jm >>> >>> >>>It isn't seeing "the draw". It is seeing "a draw". >> >> >> >>I do not know >>The score is positive at depth 2/4 when the main line is 22 plies >>so it can see advantage for white and only later changes it's opinion to draw >>score. >> >> "the draw" is way deep >>>here. "the draw" is probably beyond 40 plies deep. >> >>It is possible that it can see 40 plies at depth 3/5 or bigger depthes >>45109 positions may be enough if you search the right lines. > >There is 24 distinctive positions where the white king can go. After the move 25 >the rook can check and find that as repetition. So, that is 50 plies. However, >with check extensions it is just 25 plies. With some other extensions >this can be reduced considerably. Besides, hashtables can be tricking here the >program to see the draw earlier since 25 plies is true with a certain move >ordering. Otherwise, the hashtable will start to be filled up with draw scores >earlier (which in this case helps but it could be wrong). IMHO, I think that it >is possible that CM is seeing "the" draw. > >Regards, >Miguel > I suspect not based on the PV. Because the _first_ draw that should be seen is the deepest one. Otherwise that longest PV should be able to hide a draw until it is penetrated. With CM I could easily be wrong. But then Crafty sees the repetition as well, and I am pretty sure _it_ can not go beyond 40 plies there although I did not check this by experimentation. Nonetheless, however, I would prefer if my program solved this the same way _I_ solve it. I don't have to look at all the checks and responses. I do it with a quick static analysis to be sure that the rook checks can't be stopped by the queen nor can the king hide from them. I shudder, even if my program could find this in 1 second, because it may well reach that end position in a terminal position and say "I am a pawn ahead, I will take this and be happy" only to discover in a while that it is a draw. >> >>I do not know. >> >>Uri
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