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Subject: Re: Is this not the Botwinik position ??

Author: Dieter Buerssner

Date: 11:17:30 07/18/02

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On July 18, 2002 at 09:22:00, Uri Blass wrote:

>You remember correctly and the right line is Ba3 Qxa3 Nh5+

Yace does not agree with your "right line" after some time.

K6-2 475, in the background with about 60% CPU time.

[Ba3 also found earlier with draw score]
  15690097  3:02.7   0.00 11t  30. Ne2 Na5 31. Ba3 Qxa3 32. Qc7+ Kh6 33. Qf4+
                               Kg7 34. Qc7+ {-420}
  27202864  5:19.2   0.01 11t+ 30. Ba3 Qxa3 31. Nh5+ gxh5 32. Qg5+ Kf8 33.
                               Qxf6+ Kg8 34. Qf7+ Kh8 35. g3 Qc1+ 36. Kg2 Qc2+
                               37. Kh3 Qxc3
  28641052  5:34.9   0.41 11++ 30. Ba3 Qxa3 31. Nh5+ gxh5 32. Qg5+ Kf8 33.
                               Qxf6+ Kg8 34. Qf7+ Kh8 35. g3 Qc1+ 36. Kg2 Qc2+
                               37. Kh3 h6 38. Qf8+ Kh7 39. e7 Qe4 40. e8=Q h4
                               {501}
  50280895  9:53.0   0.85 11t  30. Ba3 Qe8 31. Qc7+ Kg8 32. Be7 Ng4 33. Qxa7
                               Nd2 34. Bg5 Nb1 35. Qd7 Qxd7 {-991}
  52940978 10:21.9   0.85 11.  30. Ba3 Qe8 31. Qc7+ Kg8 32. Be7 Ng4 33. Qxa7
                               Nd2 34. Bg5 Nb1 35. Qd7 Qxd7 {-991}
  63514652 12:28.9   1.25 12++ 30. Ba3 Qe8 31. Qc7+ Kg8 32. Be7 Ng4 33. Qd7
                               Qa8 34. Bf6 Nf2 35. Kxf2 Qf8 36. e7 Kf7 {270}
  80462007 16:05.7   2.25 12++ 30. Ba3 Qe8 31. Qc7+ Kg8 32. Be7 Ng4 33. Qd7
                               Qa8 34. Bf6 Nf2 35. Kxf2 Qf8 36. e7 Kf7 {270}
  93318518 18:28.4   2.73 12t  30. Ba3 Qe8 31. Qc7+ Kg8 32. Be7 Kg7 33. Bd8+
                               Kf8 34. Bxf6H Qxe6H 35. Bg7+H Ke8H {HT} {190}

>Ba3 is easy to find because of the draw and the real test position is to
>find Nh5+ in the following position:
>
>8/p5kp/1p2Pnp1/3pQ3/2pP4/qnP3N1/6PP/6K1 w - - 0 2
>
>It is not very hard to fail high on Nh5+ but solving the fail high seems to be a
>very hard problem for movei on p800(16 mbytes hash tables) and it's branching
>factor is not good.

I also get a bad branching factor here, when Nh5 fails high. But it is not too
surprising, IMO.

    948176   8.477   0.00  8t  2. Qc7+ Kh8 3. Qb8+ Kg7 4. Qc7+ {-420}
   1841535  17.406   0.01  8t+ 2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Qc1+ 7. Kg2 Qb2+ 8. Kh3 h6 9. Qf8+
                               Kh7 10. e7 Qxc3 11. e8=Q Nxd4 {341}
   1888582  18.853   0.40  8++ 2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Qc1+ 7. Kg2 Qb2+ 8. Kh3 h6 9. Qf8+
                               Kh7 10. e7 Qxc3 11. e8=Q Nxd4 {341}
   2215451  22.534   1.40  8++ 2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Qc1+ 7. Kg2 Qb2+ 8. Kh3 h6 9. Qf8+
                               Kh7 10. e7 Qxc3 11. e8=Q Qc1 {421}
   3656104  35.942   4.54  8t  2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Nxd4 7. e7 Qc1+ 8. Kg2 Qc2+ 9. Kh3
                               Qf5+ 10. Qxf5 Nxf5 11. e8=Q+ Kg7 12. Qd7+ Kf6
                               13. Qxa7 {501}
   3678733  36.196   4.54  8.  2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Nxd4 7. e7 Qc1+ 8. Kg2 Qc2+ 9. Kh3
                               Qf5+ 10. Qxf5 Nxf5 11. e8=Q+ Kg7 12. Qd7+ Kf6
                               13. Qxa7 {501}
   5130597  51.115   4.75  9t  2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Nxd4 7. e7 Qc1+ 8. Kg2 Qc2+ 9. Kh3
                               Qf5+ 10. Qxf5 Nxf5 11. e8=Q+ Kg7 12. Qe6 Nh6
                               13. Qe7+ Nf7H {HT} {421}
   6238514  1:00.5   4.75  9.  2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Nxd4 7. e7 Qc1+ 8. Kg2 Qc2+ 9. Kh3
                               Qf5+ 10. Qxf5 Nxf5 11. e8=Q+ Kg7 12. Qe6 Nh6
                               13. Qe7+ Nf7 {HT} {421}
   7702096  1:14.3   5.15 10++ 2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Nxd4 7. e7 Qc1+ 8. Kg2 Qc2+ 9. Kh3
                               Qf5+ 10. Qxf5 Nxf5 11. e8=Q+ Kg7 12. Qe6 Nh6
                               13. Qxd5 a6 {HT} {501}
  11492539  1:52.6   5.15 10t  2. Nh5+ gxh5 3. Qg5+ Kh8H 4. Qxf6+H Kg8H 5.
                               Qf7+H Kh8H 6. g3H Nxd4H 7. e7H Qc1+H 8. Kg2H
                               Qc2+H 9. Kg1H Ne2+H 10. Kh1H Nxg3+H 11. hxg3H
                               Qe4+H 12. Kh2H Qe2+H 13. Kh3H Qg4+H 14. Kg2H
                               {HT} {-240}
  16171881  2:34.7   5.15 10.  2. Nh5+ gxh5 3. Qg5+ Kh8 4. Qxf6+ Kg8 5. Qf7+
                               Kh8 6. g3 Nxd4 7. e7 Qc1+ 8. Kg2 Qc2+ 9. Kg1
                               Ne2+ 10. Kh1 Nxg3+ 11. hxg3 Qe4+ 12. Kh2 Qe2+
                               13. Kh3 Qg4+ 14. Kg2 {HT} {-240}

Interestingly, Nh5 is found at depth 8 here, which would suggest, that in the
original position, a fail high at depth 10 for Ba3 could be expected. But it was
only at depth 11 ...

Regards,
Dieter




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