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Up Topic Rybka Support & Discussion / Rybka Discussion / GM Ehlvest - Rybka. Game 3
- - By Victor Zakharov (*****) [ru] Date 2007-07-07 00:03 Edited 2007-07-07 00:05
[Event ""]
[Site ""]
[Date "2007.7.7"]
[Round ""]
[White "*Ehlvest"]
[Black "*Rybka"]
[Result "0-1"]
[Eco ""]
[Annotator ""]
[Source ""]

1.Nf3 d5 2.c4 dxc4 3.e3 Be6 4.Ng5 Bd5 5.e4 e6 6.exd5 Qxg5 7.dxe6
fxe6 8.d4 Qg6 9.Be2 Nf6 10.O-O Nc6 11.Bxc4 O-O-O 12.Bxe6+ Kb8
13.d5 Bc5 14.Be3 Bxe3 15.fxe3 Qg5 16.Nc3 Qxe3+ 17.Kh1 Nb4 18.Rf3
Qb6 19.a3 Nbxd5 20.Bxd5 c6 21.Rd3 cxd5 22.Nxd5 Nxd5 23.Rxd5 Rxd5
24.Qxd5 Qxb2 25.Qd6+ Ka8 26.Rf1 a6 27.h3 Re8 28.Rf7 h5 29.Kh2
g5 30.Rf5 Qg7 31.Qg3 Rg8 32.h4 gxh4 33.Qxg7 Rxg7 34.a4 Rg4 35.a5
b5 36.Rf8+ Kb7 37.Rf7+ Kc6 38.Rf6+ Kc5 39.Rxa6 Kb4 40.Ra8 Ka3
41.Rb8 b4 42.a6 Rg7 43.Rb7 Rg5 44.Kh3 Ra5 45.Kxh4 b3 46.a7 Kb2
47.g3 Kc3 48.Rc7+ Kb4 49.Rb7+ Ka4 50.Rh7
( 50.Rb6 Ka3 51.Rb8
Rxa7 52.Kxh5 Ra5+ 53.Kg6 Ra4 54.Kf5 Rb4 55.Ra8+ Kb2 56.g4 Rb5+
{(0:05.36) [= (+0.00)] d=34} {Rybka v2.3.2r1.mp.x64 -} )
b2 51.Rb7 Ka3 52.Rb5 Rxa7 53.Kxh5 Ra4 54.Rxb2 Kxb2 55.g4 Kc3 56.g5 Kd4
57.g6 Ke5 0-1
Parent - By turbojuice1122 (Gold) [us] Date 2007-07-07 01:46
It looks like Rybka blundered big with 40...Ka3?? as 40...Rg5 keeps the advantage.
Parent - - By MoKy (**) [sk] Date 2007-07-07 02:22 Edited 2007-07-07 03:17
[Event "Handicap Match II Crazy Book"]
[Site "Potomac, Maryland"]
[Date "2007.07.07"]
[Round "2.3"]
[White "Ehlvest, Jaan"]
[Black "Rybka 232a"]
[Result "0-1"]
[ECO "A09"]
[WhiteElo "3100"]
[BlackElo "2650"]
[Annotator "MoKy"]
[PlyCount "114"]

1. Nf3 d5 2. c4 dxc4 3. e3 Be6 4. Ng5 Bd5 5. e4 e6 6. exd5 Qxg5 7. dxe6 fxe6 8.
d4 Qg6 9. Be2 Nf6 10. O-O Nc6 11. Bxc4 O-O-O 12. Bxe6+ Kb8 13. d5 Bc5 14. Be3
Bxe3 15. fxe3 Qg5 16. Nc3 Qxe3+ 17. Kh1 Nb4 18. Rf3 Qb6 19. a3 Nbxd5 20. Bxd5
c6 21. Rd3 cxd5 22. Nxd5 Nxd5 23. Rxd5 Rxd5 24. Qxd5 Qxb2 25. Qd6+ Ka8 26. Rf1
a6 27. h3 Re8 28. Rf7 h5 29. Kh2 g5 30. Rf5 Qg7 31. Qg3 Rg8 32. h4$2


k5r1/1p4q1/p7/5Rpp/7P/P5Q1/6PK/8 b - - 0 32

                                                                        into rook ending

(32. Rd5 h4 33. Qe5 Qxe5+ 34. Rxe5 b5 35. g3 Kb7 36. Kg2) 32... gxh4 33. Qxg7 Rxg7
34. a4
(34. Rxh5 Rg4 35. Kh3 Rg3+ 36. Kh2 Rxa3 37. Rxh4 Rc3$1 38. g4 Rc8 39. g5 b5
40. Kg3 a5 41. Kf4 a4 42. g6 Rg8 43. Kf5 a3 44. Rh1 b4 45. Ra1 Ka7$1 46. Kf6
Kb6 47. Kf7 Ra8 $19) 34... Rg4 35. a5 b5 36. Rf8+ (36. axb6 Kb7 37. Rxh5 Kxb6
38. Kh3 Rf4 $19) 36... Kb7 37. Rf7+ Kc6 38. Rf6+ Kc5 39. Rxa6 Kb4$2 (39... Ra4$1

8/8/R7/Ppk4p/r6p/8/6PK/8 w - - 0 40

                                                                          behind pawn

40. Ra8 b4 41. a6 Kb6 42. Rb8+ 42... Ka7$1 (42... Kxa6$2 43. Kh3 Ka5
44. Kxh4$1 b3+ 45. Kxh5 Rb4 46. Ra8+ Kb5 47. Ra1 b2 48. Rb1 $11)

43. Rb7+ Kxa6 44. Rb8 Ka5 45. Kh3 Ra3+ 46. Kxh4 Ka4 $19)
40. Ra8 Ka3 41. Rb8$1 (41. a6$2 Ra4 $19) 41... b4 42. a6 Rg7
43. Rb7
(43. Kh3$1 easy way b3 (43... Ra7 44. Rb6 $11 black rook is in offside)
44. Kxh4 b2 45. Kxh5 $11) 43... Rg5 44. Kh3 Ra5 45. Kxh4 b3 46. a7 Kb2
(46... b2 47. g3$3

8/PR6/8/r6p/7K/k5P1/1p6/8 b - - 0 47

                                                      mutual zugzwang (black to move draws)

47... Ka2 loses control over b4 48. Rb8 (48. a8=Q$2 Rxa8 guards promotion
square of g-pawn 49. Kxh5 b1=Q $19)
48... Rxa7 49. Kxh5 Ra3 50. g4 Rb3
51. Ra8+ Kb1 52. Rc8$3 $11) 47. g3 (47. Rb8$1 Rxa7 48. Kxh5 $11)
47... Kc3 48. Rc7+ (48. Rb8$2 Rxa7 49. Kxh5 Ra4$1 50. g4 Rb4
51. Rc8+ Kd2 52. Rd8+ Ke2 53. Re8+ Kf2 54. Rf8+ Kg2 $19) 48... Kb4
49. Rb7+ Ka4$1 50. Rh7$2
(50. Rb8 Rxa7 51. Kxh5 Ra5+ 52. Kh6 Rb5
53. Ra8+ Kb4 54. Ra1 b2 55. Rb1 Kc3 56. g4 $11) 50... b2 51. Rb7 Ka3

8/PR6/8/r6p/7K/k5P1/1p6/8 w - - 0 52

                                                      mutual zugzwang (white to move loses)

52. Rb5 Rxa7 53. Kxh5 Ra4$1 54. Rxb2 Kxb2 55. g4 Kc3 56. g5 Kd4 57. g6 Ke5 0-1

Mario
Parent - - By Vasik Rajlich (Silver) [hu] Date 2007-07-07 10:54
This is accurate analysis, thanks. I was a bit puzzled by this ending last night, but now all is clear. The key to understanding this rook endgame is realizing that the following positon is reciprocal zugzwang:

8/PR6/8/r6p/7K/k5P1/1p6/8 w - - 0 1


This position arose in the game with white to move on move 52, and could have arisen with black to move if black had played 46. .. b3.

With white to move, the situation is quite straightforward:

a) 1. a8 loses to 1. .. Rxa8 2. Kxh5 Ra4! (a common rook-ending idea) 3. Rxb2 (else black plays 3. .. Rb4) Kxb2 and black is in time to stop the g-pawn.
b) 1. Rb5 loses in the exact same way: 1. .. Rxa7 2. Kxh5 Ra4! 3. Rxb2 ..
c) 1. g4 is obviously losing
d) 1. Kh3 costs white a tempo and loses to 1. .. Ka2 etc

With black to move, quite incredibly, the obvious 1. .. Ka2 actually leaves the king on a worse square and allows black to draw with 2. Rb5 Rxa7 3. Kxh5 and now:

a) 3. .. b1Q 4. Rxb1 Kxb1 5. g4 with a drawn kr vs kp endgame (with the black king on b2 it would be winning for black)
b) 3. .. Ra3 (analogous to 2. .. Ra4 in the above lines) is met calmly with 4. g4 Rb3 5. Ra5+ and black's king does not have a hiding square (with the king on a3 and rook on b4, the king can slide into b3)

It's amazing what sorts of resources can hide in such a simple-looking position.

Curiously, Rybka made one mistake in this game - 39. .. Kb4. This mistake is caused by a lack of KRKP tablebases - with these and nothing else, she should play everything correctly. She needs these tablebases to correctly understand on move 39 that 46. .. b3 47. Rb5 Rxa7 48. Kxh5 b1Q 49. Rxb1 Kxb1 is drawn. Searching all the way to the K vs K draw back on move 39 will take too long. FWIW - the no-tablebase rule is a bit unfair :), since if tablebases did not exist, I would have already given Rybka some simple heuristics for KRKP. But that's another discussion ..

Vas
Parent - By Linus (***) [at] Date 2007-07-07 12:01
Apparently Ehlvest had his tablebases deactivated too. ;) He missed several drawing possibilities, e.g. after 46...Kb2 he played to more complicated 47.g3 when 47.a8Q Rxa8 48.Kxh5 would have lead to an immediate and easy draw.
Parent - - By Jim Walker (***) [us] Date 2007-07-07 13:21
Hello Vas,
I agree about no TBs for Rybka.  Rybka is not a "mature" program where a lot of endgame problems are already solved.   Tablebases save a lot of work in finding and solving these little hidden problems.  A young program like Rybka depends on the TBs for answers.  I must admit I have more respect for Elhvest now.  Even his Rh7? seems to have been made is some time trouble.  Was that the case?
Jim
Parent - By lkaufman (*****) Date 2007-07-07 16:32
yes
Parent - - By George Tsavdaris (****) Date 2007-07-07 17:06
The line you give 39...Ra4! as a win for black is actually a draw.
You give 39...Ra4! 40.Ra8 that you prove it wins but the 40.Ra8? is bad.
After 40.Rh6! for white then black has only a draw. See my analysis....

So 39...Ra4? is also bad along with what rybka played.
The only moves that deserve to explore for black are: 39...b4 and 39...Rg8

Here is the new analysis, for the aforementioned 40.Ra8? move, over yours:

[Event "Handicap Match II Crazy Book"]
[Site "Potomac, Maryland"]
[Date "2007.07.07"]
[Round "2.3"]
[White "Ehlvest, Jaan"]
[Black "Rybka 232a"]
[Result "0-1"]
[ECO "A09"]
[WhiteElo "3100"]
[BlackElo "2650"]
[Annotator "MoKy"]
[PlyCount "114"]

1. Nf3 d5 2. c4 dxc4 3. e3 Be6 4. Ng5 Bd5 5. e4 e6 6. exd5 Qxg5 7. dxe6 fxe6 8.
d4 Qg6 9. Be2 Nf6 10. O-O Nc6 11. Bxc4 O-O-O 12. Bxe6+ Kb8 13. d5 Bc5 14. Be3
Bxe3 15. fxe3 Qg5 16. Nc3 Qxe3+ 17. Kh1 Nb4 18. Rf3 Qb6 19. a3 Nbxd5 20. Bxd5
c6 21. Rd3 cxd5 22. Nxd5 Nxd5 23. Rxd5 Rxd5 24. Qxd5 Qxb2 25. Qd6+ Ka8 26. Rf1
a6 27. h3 Re8 28. Rf7 h5 29. Kh2 g5 30. Rf5 Qg7 31. Qg3 Rg8 32. h4 {?} (32. Rd5
h4 33. Qe5 Qxe5+ 34. Rxe5 b5 35. g3 Kb7 36. Kg2 Kb6 37. Re6+ (37. Kf3 Ka5 38.
Re4 hxg3 39. Rg4 Rc8 40. Kxg3 Rc3+ 41. Kg2 Rxa3 42. Rxg5 Ka4 43. h4 Rc3) (37.
Re4 hxg3 38. Kxg3 Rc8 39. Re3 Rc4) 37... Ka5 38. Re4 (38. g4 Rc8 39. Rg6 Rc2+
40. Kg1 Rc3 41. Kg2 Rxa3 42. Rxg5 Ra2+) 38... hxg3 39. Kxg3 Rc8 40. Rg4 Rc4 41.
Rxg5 Rc3+ 42. Kg4 Rxa3 43. h4 Ra1 44. h5 Rh1 45. Kf3 Rc1 46. Kg4 Ka4 47. h6 Rc8
) 32... gxh4 33. Qxg7 Rxg7 34. a4 (34. Rxh5 Rg4 35. Kh3 Rg3+ 36. Kh2 Rxa3 37.
Rxh4 Rc3 {!} 38. g4 Rc8 39. g5 b5 40. Kg3 a5 41. Kf4 a4 42. g6 Rg8 43. Kf5 a3
44. Rh1 b4 45. Ra1 Ka7 {!} 46. Kf6 Kb6 47. Kf7 Ra8) 34... Rg4 35. a5 b5 36.
Rf8+ (36. axb6 Kb7 37. Rxh5 Kxb6 38. Kh3 Rf4) 36... Kb7 37. Rf7+ Kc6 38. Rf6+
Kc5 39. Rxa6 Kb4 {?} (39... Ra4 {?} 40. Ra8 (40. Rh6 Kb4 (40... Kc4 41. Rxh5 b4
42. Rxh4+ Kc3 43. Rh3+ {Draw!}) (40... b4 41. Rxh5+ Kc4 42. Rxh4+ Kc3 43. Rh3+
{Draw!}) 41. a6 Kc3 (41... Kc4 42. Rxh5 b4 43. Rxh4+ Kb5 (43... Kc3 44. Rh3+ {
Draw!}) 44. Kg3 Rxa6 {Draw!}) (41... Ka3 42. Kh3 b4 43. Kxh4 Ra5 44. Rxh5 Rxa6
{Draw!}) 42. Kh3 b4 43. Kxh4 Ra5 44. Rxh5 Rxa6 {And draw!}) 40... b4 41. a6 Kb6
42. Rb8+ Ka7 {!} (42... Kxa6 {?} 43. Kh3 Ka5 44. Kxh4 {!} b3+ 45. Kxh5 Rb4 46.
Ra8+ Kb5 47. Ra1 b2 48. Rb1 {=}) 43. Rb7+ Kxa6 44. Rb8 Ka5 45. Kh3 Ra3+ 46.
Kxh4 Ka4) (39... b4 {The most promising move.} 40. Ra8 {
Now things are very complicated and i don't have enough time.}) (39... Rg8 {
Clever move and very promising. no time to analyse it now.}) 40. Ra8 Ka3 41.
Rb8 {!} (41. a6 {?} Ra4) 41... b4 42. a6 Rg7 43. Rb7 (43. Kh3 {!  easy way} b3
(43... Ra7 44. Rb6 {= black rook is in offside}) 44. Kxh4 b2 45. Kxh5 {=})
43... Rg5 44. Kh3 Ra5 45. Kxh4 b3 46. a7 Kb2 (46... b2 47. g3 {!!} Ka2 {
loses control over b4} 48. Rb8 (48. a8=Q {?} Rxa8 {
guards promotion square of g-pawn} 49. Kxh5 b1=Q) 48... Rxa7 49. Kxh5 Ra3 50.
g4 Rb3 51. Ra8+ Kb1 52. Rc8 {!!  =}) 47. g3 (47. Rb8 {!} Rxa7 48. Kxh5 {=})
47... Kc3 48. Rc7+ (48. Rb8 {?} Rxa7 49. Kxh5 Ra4 {!} 50. g4 Rb4 51. Rc8+ Kd2
52. Rd8+ Ke2 53. Re8+ Kf2 54. Rf8+ Kg2) 48... Kb4 49. Rb7+ Ka4 {!} 50. Rh7 {?}
(50. Rb8 Rxa7 51. Kxh5 Ra5+ 52. Kh6 Rb5 53. Ra8+ Kb4 54. Ra1 b2 55. Rb1 Kc3 56.
g4 {=}) 50... b2 51. Rb7 Ka3 52. Rb5 Rxa7 53. Kxh5 Ra4 {!} 54. Rxb2 Kxb2 55. g4
Kc3 56. g5 Kd4 57. g6 Ke5 0-1
Parent - By MoKy (**) [sk] Date 2007-07-07 22:01
Thanks George
You have true Ra4 is draw after Rh6 and Ra8 as well.
I analysed your suggestions, notably Rg8 could cause some troubles to white. However, I didnt find any winning plan.
Here is my restored analysis of third game.

[Event "Handicap Match II Crazy Book"]
[Site "Potomac, Maryland"]
[Date "2007.07.06"]
[Round "2.3"]
[White "Ehlvest, Jaan"]
[Black "Rybka 2.32a"]
[Result "0-1"]
[ECO "A09"]
[WhiteElo "2650"]
[BlackElo "3100"]
[Annotator "MoKy"]
[PlyCount "114"]

1. Nf3 d5 2. c4 dxc4 3. e3 Be6 4. Ng5 Bd5 5. e4 e6 6. exd5 Qxg5 7. dxe6 fxe6 8.
d4 Qg6 9. Be2 Nf6 10. O-O Nc6 11. Bxc4 O-O-O 12. Bxe6+ Kb8 13. d5 Bc5 14. Be3
Bxe3 15. fxe3 Qg5 16. Nc3 Qxe3+ 17. Kh1 Nb4 18. Rf3 Qb6 19. a3 Nbxd5 20. Bxd5
c6 21. Rd3 cxd5 22. Nxd5 Nxd5 23. Rxd5 Rxd5 24. Qxd5 Qxb2 25. Qd6+ Ka8 26. Rf1
a6 27. h3 Re8 28. Rf7 h5 29. Kh2 g5 30. Rf5 Qg7 31. Qg3 $1 Rg8 32. h4 $3 gxh4
33. Qxg7 Rxg7 34. a4 $1 Rg4 35. a5 b5 36. Rf8+ $1 Kb7 37. Rf7+ Kc6 38. Rf6+ Kc5
39. Rxa6 Kb4 (39... Ra4 40. Rh6 (40. Ra8 b4 41. a6 Kb6 42. Rb8+ Ka7 $1 43. Rb7+
Kxa6 44. Rb8 Ka5 45. Kh3 Ra3+ 46. Kxh4 Ka4 47. Rg8 $3 b3 $1 48. Ra8+ $1 Kb4 49.
Rb8+ Kc3 50. Rc8+ Kd2 51. Rd8+ Kc2 52. Rc8+ Kb1 53. Kxh5 Ka2 54. g4 b2 55. Rc2
$11) 40... Kb4 41. a6 Ka3 42. Kh3 b4 43. Kxh4 b3+ 44. Kxh5 Ra5+ 45. Kh4 $11) (
39... b4 40. Ra8 b3 41. Rb8 Kc4 (41... Rb4 42. Rxb4 Kxb4 43. a6 b2 44. a7 b1=Q
45. a8=Q $11) 42. a6 Rg7 43. Kh3 Ra7 44. Rb6 Kc3 45. Kxh4 b2 46. Rc6+ $1 Kb3
47. Rb6+ Ka2 48. Kxh5 $11) (39... Rg8 $1 40. Rh6 (40. Ra7 b4 41. a6 b3 42. Rb7
Kc4 43. a7 Ra8 44. Kh3 Kc3 45. Kxh4 b2 46. Rc7+ $1 Kd2 47. Rd7+ Kc1 48. Rc7+
Kb1 49. Kxh5 Ka1 50. Rb7 b1=Q 51. Rxb1+ Kxb1 52. g4 Kc2 53. g5 Kd3 54. Kg6 $1
Ke4 55. Kf6 Kf4 56. g6 Kg4 57. g7 Kh5 58. Kf7 $11) 40... b4 41. Rxh5+ Kc4 42.
Rxh4+ Kc3 43. Rh7 $2 (43. g4 $1 b3 44. Kg3 b2 45. Rh1 Ra8 46. Kf4 Rxa5 47. Rb1
$1 $11) 43... b3 44. a6 (44. Kh3 b2 45. Rb7 Rh8+ 46. Kg4 Rh1 47. Kf5 b1=Q+ 48.
Rxb1 Rxb1 $19) 44... b2 45. Rb7 Ra8 $2 (45... Kc2 46. Kh3 b1=Q 47. Rxb1 Kxb1
$19) 46. a7 Kc2 47. Rc7+ Kb3 48. Rb7+ Ka2 49. g4 b1=Q 50. Rxb1 Kxb1 51. Kg3 $1
Kc2 52. Kf4 Kd3 53. Ke5 $3 {Reti's manoeuvre} Ke3 54. g5 Kf3 55. g6 Kg4 56. g7
$1 Kg5 57. Kd6 Kf6 58. Kc6 $11) 40. Ra8 Ka3 41. Rb8 $1 b4 42. a6 Rg7 43. Rb7 (
43. Kh3 $1 b3 44. Kxh4 b2 45. Kxh5 $11) 43... Rg5 44. Kh3 Ra5 45. Kxh4 b3 46.
a7 Kb2 (46... b2 47. g3 $3 $11 {reciprocal zugzwang} Ka2 48. Rb8 Rxa7 49. Kxh5
Ra3 50. g4 Rb3 51. Ra8+ Kb1 52. Rc8 $3 $11) 47. g3 (47. Rb8 Rxa7 48. Kxh5 $11)
47... Kc3 48. Rc7+ Kb4 49. Rb7+ Ka4 $1 (49... Ka3 50. Rb8 Rxa7 51. Kxh5 Ra5+
52. Kg6 Ra4 53. Kf5 b2 54. Rxb2 $11) 50. Rh7 $2 (50. Rb8 Rxa7 51. Kxh5 Ra5+ 52.
Kh6 Rb5 53. Ra8+ Kb4 54. Ra1 b2 55. Rb1 Kc3 56. g4 $11) 50... b2 51. Rb7 Ka3
$19 {reciprocal zugzwang} 52. Rb5 Rxa7 53. Kxh5 Ra4 $1 54. Rxb2 Kxb2 55. g4 Kc3
56. g5 Kd4 57. g6 Ke5 0-1
Up Topic Rybka Support & Discussion / Rybka Discussion / GM Ehlvest - Rybka. Game 3

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