Rybka 3: <using 6-piece tablebases>

 

[-1.24]  d=38  46.h4+ Kh6 47.Rf4 Rc3+ 48.f3 a5 49.Rd4 Rb3 50.Rd8 Rb4 51.Rd6 Kg7 52.Rc6 Rxa4 53.Rxb6 Rb4 54.Ra6 a4 55.Rd6 Kf7 56.Ra6 Rc4 57.Kh3 Rd4 58.Kg3 Kg7 59.Rb6 Kh7 60.Rb7+ Kg8 61.Ra7 16:06:48  1057816kN, tb=64048

 

Section II: After suggested improvement 45...h5 46.h4+ Kh6 47.Rf4 Rc5:

 

Rybka 3: <using 5-piece tablebases>

 

[-1.12]  d=36  48.f3 Kg7 49.Rd4 Kf6 50.Kf4 Ke6 51.Rd8 Ra5 52.Rd4 Rf5+ 53.Ke4 Re5+ 54.Kf4 Rd5 55.Rc4 03:09:08  8877kN, tb=369 6piece TB

 

[-1.11]  d=33  48.f3 Kg7 49.Rd4 Kf6 50.Kf4 Rf5+ 51.Ke4 Ke7 52.Ke3 Ra5 53.Ke4 Ke6 54.Kf4

 

[-1.30]  d=32  48.Rb4 Kg7 49.Rd4 Kf6 50.Rd6+ Kf5 51.f3 Ra5 52.Rd4 Ke5 53.Re4+ Kd6 54.f4 Rd5 55.Re8 Rd3+ 56.Kg2 Ra3 57.Rg8 Ke6 58.Rxg6+ Kf5 59.Rg5+ Kxf4 60.Rxh5 Kg4 61.Rd5 Ra2+ 62.Kf1 Rxa4 63.h5

 

 

[-1.12]  d=33  49.Kf4 Kg7 50.Rc4 Rf5+ 51.Ke3 Rc5 52.Rd4 Kf6 53.f3 Kf5 54.Rf4+ Ke6 55.Rb4 Rc3+ 56.Kf4 Kf6 57.Rd4 04:14:58  187952kN, tb=25334

 

 

Rybka 3:

 

[-1.80]  d=28   42.a3 Rd5 43.h4+ Kf6 44.Rf3+ Kg7 45.Bb3 Rd4 46.Bc2 19:03:31 4.588.750,840 96.520 

 

[-1.93]  d=28   42.Rf3 Rc4 43.Bd1 Rb4 44.Re3 Rb2 45.a3 Kf6 46.f4 a4 47.Kf3 Rb1 48.Ke2 Ra1 49.Bc2 b5 19:03:31 6.581.337,617 98.223

 

Section V: After 40.Kf3:  Rybka3

 

 

<28-ply>

 

[-1.99] 40...a5 41.Bb1 Ke5 42.Rc1 Kd5 43.Ke3 Ra4 44.Rh1 b5 45.f3 Ke5 46.Re1 Rc4 47.Re2 b4 48.Rc2

[-1.96] 40...Ke5 41.Re3+ Kd6 42.Re1 a5 43.Rb1 Kc6 44.Rh1 Rb4 45.Bb1 b5 46.h4 Rb2

 

[-1.96] 40...Ke6 41.Re3+ Kd6 42.Re1 a5 43.Rb1 Kc6 44.Rh1 Rb4 45.Bb1 b5 46.h4 Rb2

 

<27-ply>

 

1. -+  (-1.95): 40...a5 41.Bb1 Ke5 42.Rc1 Kd5 43.Ke3 Ra4 44.Rh1 b5 45.f3 Ke5 46.Re1 Rc4 47.Re2 b4 48.Rc2

 

 

3. -+  (-1.89): 40...Ke6 41.Kg3 Rd2 42.Kf3 Ke5 43.Ke3 Rd4 44.Bb3

 

<26-ply>

 

 -+  (-1.84): 40...a5 41.Kg3 a4 42.h4 Ke5 43.Re3+ Kd6 44.h5 gxh5 45.Bxh7 h4+ 46.Kg2 b5 47.Re8 Rf4 48.f3 b4 49.Bg8 Nd7 50.Ra8 Rf8 51.Ra6+ Kc5 52.Ra5+ Kb6 53.Rg5

 -+  (-1.84): 40...Ke5 41.Re3+ Kd6 42.Re1 a5 43.Rb1 Kc6 44.Rh1

 -+  (-1.63): 40...Kg5 41.Kg2 a5 42.Kg3 Rb4 43.a3 Rd4 44.Kf3 Kf6

 

JLJ Dec-08-2009
 

 

Additional Information:

 

From the ICGA Journal of December, 2000:

According to Van Reek (1998), the winning variation starts with <45. ... h5!!> A strategy of active consolidation begins. The first key move consolidates the King's side. <46. h4+ Kh6>. A tactical justification of the variation is 47. a5 b5! 48. Rf6!? b4 49. a6!? b3 50. Rf3 b2 51. Rb3 Rc3+! <47. Rf4 Rc5!> The second key move starts a consolidation of the Queen's side. <48. Rd4 Ra5>. The flanks are now consolidated by Black, and he is ready for activity. The black moves were calculated by the computers. For instance, the programs investigated 45. ... Rc4? Botvinnik (1985) refuted this move by 46. a5 bxa5 47. Rf7 a6 48. h4+ Kh6 49. Rd7! In the evaluations by FRITZ 6, 45. ... h5 became choice nine from nineteen potential moves. Other moves calculated by FRITZ 6 were 47. ... Rc3+ 48. f3 a5? and 48. ... a5? HIARCS 7.32 computed 47. ... a5? and 48. ... b5? These moves weaken the b-Pawn, an essential asset of Black's position.

The second variation continues with <49. f4>. White prevents ... g5. <49. ... Kg7>. Black begins a strategy of restriction by moving his King to the central area. <50. Kf3 Kf6 51. Ke4 Ke6 52. Rc4 Rc5 53. Rb4>. Both programs had no difficulty in finding the central movement by the black King. Diagram 3 has been reached. If White has to move, Black wins. Therefore Black plays <53. ... Ke7>! The first key move: the black King begins a triangle manoeuvre <54. Kd3 Kf6 55. Ke4 Ke6>. A move exchange has been completed. The programs computed 53. ... Rc6!? This move seems to be a dual win (54. a5 bxa5 55. Ra4 Rc5 56. Ra2 Rb5!). HIARCS 7.32 confirmed the other two moves by Black in the second variation. FRITZ 6 gave 54. ... Kf6 and 54. ... Kf7 as equal choices and calculated 55. ... Rc6?! <56. Rd4 a5!> The second key move completes the zugzwang manoeuvre. <57. Ke3 Rc3+ 58. Ke4 Rb3 59. Rc4 Rb4> and wins. Both programs confirmed the last four moves by Black.