Author: Rafael Andrist
Date: 01:49:11 09/14/03
Go up one level in this thread
On September 13, 2003 at 19:03:41, John Merlino wrote:
>On September 13, 2003 at 18:00:18, Rafael Andrist wrote:
>
>>On September 13, 2003 at 14:34:26, John Merlino wrote:
>>
>>>On September 13, 2003 at 14:31:55, Rafael Andrist wrote:
>>>
>>>>On September 13, 2003 at 14:08:37, John Merlino wrote:
>>>>
>>>>>On September 13, 2003 at 10:23:41, Frank Phillips wrote:
>>>>>
>>>>>>[D]8/4k3/8/8/4Kp1p/5N1N/8/8 w - -
>>>>>>
>>>>>>Just an amusing position.
>>>>>>
>>>>>>White to move and win. Perhaps the longest forced mate my program has played.
>>>>>>I was not sure whether it would be caught out by the 50 moves rule. (Any credit
>>>>>>goes to Eugene of course.).
>>>>>>
>>>>>>It traded down from B+Pawns versus 2N+Pawns to reach this endgame. My heart
>>>>>>sank and I was already to fix yet another evaluation quirk - maybe still need
>>>>>>to.
>>>>>>
>>>>>>Frank
>>>>>
>>>>>Kxf4 is a forced mate in 90 moves and it will NOT be caught by the 50-move rule.
>>>>
>>>>No, after Kxf4 it is a draw. You need 51 moves to the next forced capture/pawn
>>>>push with best defence.
>>>>
>>>>Also, I did a short search up to depth 13 and could not find a win which would
>>>>not have been prohibited by the 50-move rule.
>>>>
>>>>The endgame is anyway only won in about 23% of all cases and even then, you will
>>>>fail to win it in more than 50% without the appropriate endgame tables.
>>>>
>>>>regards
>>>>Rafael B. Andrist
>>>
>>>You're probably right, since Black has many options. But can you prove it by
>>>posting the moves?
>>
>>What kind of moves are you interested in? The optimal line of play or optimal
>>defense vs. DTM attacker?
The optimal line of play with DTZ metric goes as follows:
White wins: win in -51
on the move lengthens win by 1
optimal moves: Ke7-d6 {#-51}
suboptimal moves: Ke7-d8 {#-50}, Ke7-e8 {#-50}, Ke7-e6 {#-50}, Ke7-d7 {#-49},
Ke7-f6 {#-44}, Ke7-f8 {#-40}, Ke7-f7 {#-40}
1... Ke7-d6! 2. Nf3-d4 Kd6-d5! 3. Nd4-f5! Kd5-c5! 4. Kf4-e4 Kc5-c6! 5. Ke4-d4
Kc6-b6 6. Nf5-e7 Kb6-b5 7. Kd4-d5! Kb5-b6! 8. Ne7-g6! Kb6-c7! 9. Ng6-f8! Kc7-b6
10. Nf8-e6! Kb6-b5! 11. Ne6-c7+! Kb5-b4! 12. Kd5-d4! Kb4-b3! 13. Nc7-d5! Kb3-c2!
14. Nd5-b4+ Kc2-d2 15. Nb4-d3! Kd2-d1! 16. Kd4-c3! Kd1-e2° 17. Nd3-f2 Ke2-e3!
18. Kc3-c4! Ke3-d2! 19. Kc4-b3! Kd2-e2! 20. Kb3-c2! Ke2-e3! 21. Kc2-c3! Ke3-e2!
22. Kc3-d4! Ke2-d2 23. Nf2-g4! Kd2-c2! 24. Kd4-c4! Kc2-b2! 25. Nh3-f2 Kb2-a3!
26. Nf2-d3! Ka3-a4! 27. Nd3-b4!! Ka4-a5! 28. Kc4-c5!! Ka5-a4! 29. Nb4-c6!
Ka4-b3! 30. Kc5-d4!! Kb3-c2! 31. Ng4-h2 Kc2-d2! 32. Nc6-e5! Kd2-c2! 33. Nh2-f3
Kc2-b2 34. Ne5-c6 Kb2-a2 35. Nc6-a5 Ka2-b2! 36. Kd4-d3! Kb2-a3! 37. Kd3-c4!
Ka3-b2! 38. Na5-b7! Kb2-c2! 39. Nb7-d6! Kc2-b2! 40. Nd6-b5! Kb2-c2! 41. Nb5-a3+!
Kc2-b2! 42. Kc4-b4! Kb2-c1! 43. Kb4-c3! Kc1-d1! 44. Kc3-d3!! Kd1-c1! 45. Na3-c4!
Kc1-d1! 46. Nc4-b2+! Kd1-c1° 47. Kd3-c3! Kc1-b1! 48. Nb2-d3! Kb1-a2! 49. Kc3-b4!
Ka2-a1! 50. Kb4-a3 Ka1-b1! 51. Ka3-b3! {Draw due to 50 move rule} Kb1-a1! 52.
Nf3-d2! h4-h3° 53. Nd3-c1 {Stalemate trap} h3-h2° 54. Kb3-c2 h2-h1Q 55.
Nd2-b3#!!
The credits go to E. Nalimov for his EGTB code and to Marc Bourzutschky for
modifiying it to create DTC, DTZ and DTZ50 endgame tables.
At the ACG10 conference in Graz, there will the presentation of a paper written
by G. Haworth and John Tamplin about these different metrics and strategies how
to use them.
regards
Rafael B. Andrist
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