Possible draw bug in Thinker

[Robert Allgeuer]

Geschrieben von:/Posted by: Robert Allgeuer at 08 June 2004 22:30:09:

This is a game of the old version 4.5b of Thinker. It is known that this version does incorrect draw claims; this has been fixed in more recent releases. I nevertheless post this game, because this one may on top of that indicate that the underlying KPK recogniser incorrectly recognises this endgame with g pawn as draw, because in fact this game is lost as opposed to what Thinker thinks.
Robert

[Event "Aristarch 4.50 gauntlet"]
[Site "DISCO"]
[Date "2004.05.28"]
[Round "15.1"]
[White "Aristarch v4.50"]
[Black "Thinker v4.5b"]
[Result "1/2-1/2"]
[TimeControl "300+2"]
[Number "2395"]
1. c4 Nf6 2. Nf3 e6 3. g3 Be7 4. Bg2 d5 5. d4 O-O 6. Qc2 dxc4 7. Qxc4 a6 8.
Bf4 Nd5 9. Bd2 Bd7 10. Nc3 b5 11. Qb3 Bc6 12. O-O Nd7 13. a4 bxa4 14. Nxa4
Bb5 15. Rfe1 c5 16. Nc3 Nxc3 17. Bxc3 Nb6 18. dxc5 Bxc5 19. Red1 Qc7 20.
Be5 Qe7 21. Nd4 Bc4 22. Qc3 f6 23. Nc6 Qb7 24. Bf4 Rac8 25. b4 Bd5 26. bxc5
Bxg2 27. Na5 Qa8 28. Bd6 Rfe8 29. Rab1 Nd5 30. Qc4 Nc7 31. f3 Bh3 32. Qh4
Bf5 33. e4 Bg6 34. Rb7 Nb5 35. e5 Nxd6 36. cxd6 Rb8 37. Qb4 Rxb7 38. Qxb7
Bc2 39. Ra1 fxe5 40. d7 Rd8 41. Qxa8 Rxa8 42. Nb7 Kf7 43. d8=Q Rxd8 44.
Nxd8+ Ke7 45. Nc6+ Kf6 46. Rxa6 g5 47. Ra5 e4 48. f4 h6 49. Nd4 Bd3 50. Re5
Bc4 51. Rxe4 Ba2 52. fxg5+ hxg5 53. h4 gxh4 54. Rxh4 e5 55. Nc6 Bd5 56.
Nxe5 Kxe5 57. Rh5+ Ke4 58. Rxd5 Kxd5 59. Kh2 Ke5 60. Kh3 Kf5 61. Kh4 { draw
} 1/2-1/2

[Rafael Peña]

Geschrieben von:/Posted by: Rafael Peña at 09 June 2004 00:07:22:
Als Antwort auf:/In reply to: Possible draw bug in Thinker geschrieben von:/posted by: Robert Allgeuer at 08 June 2004 22:30:09:

hello!
just a question, why post a bug from a old engine?
Rafael Peña

This is a game of the old version 4.5b of Thinker. It is known that this version does incorrect draw claims; this has been fixed in more recent releases. I nevertheless post this game, because this one may on top of that indicate that the underlying KPK recogniser incorrectly recognises this endgame with g pawn as draw, because in fact this game is lost as opposed to what Thinker thinks.
Robert
[Event "Aristarch 4.50 gauntlet"]
[Site "DISCO"]
[Date "2004.05.28"]
[Round "15.1"]
[White "Aristarch v4.50"]
[Black "Thinker v4.5b"]
[Result "1/2-1/2"]
[TimeControl "300+2"]
[Number "2395"]
1. c4 Nf6 2. Nf3 e6 3. g3 Be7 4. Bg2 d5 5. d4 O-O 6. Qc2 dxc4 7. Qxc4 a6 8.
Bf4 Nd5 9. Bd2 Bd7 10. Nc3 b5 11. Qb3 Bc6 12. O-O Nd7 13. a4 bxa4 14. Nxa4
Bb5 15. Rfe1 c5 16. Nc3 Nxc3 17. Bxc3 Nb6 18. dxc5 Bxc5 19. Red1 Qc7 20.
Be5 Qe7 21. Nd4 Bc4 22. Qc3 f6 23. Nc6 Qb7 24. Bf4 Rac8 25. b4 Bd5 26. bxc5
Bxg2 27. Na5 Qa8 28. Bd6 Rfe8 29. Rab1 Nd5 30. Qc4 Nc7 31. f3 Bh3 32. Qh4
Bf5 33. e4 Bg6 34. Rb7 Nb5 35. e5 Nxd6 36. cxd6 Rb8 37. Qb4 Rxb7 38. Qxb7
Bc2 39. Ra1 fxe5 40. d7 Rd8 41. Qxa8 Rxa8 42. Nb7 Kf7 43. d8=Q Rxd8 44.
Nxd8+ Ke7 45. Nc6+ Kf6 46. Rxa6 g5 47. Ra5 e4 48. f4 h6 49. Nd4 Bd3 50. Re5
Bc4 51. Rxe4 Ba2 52. fxg5+ hxg5 53. h4 gxh4 54. Rxh4 e5 55. Nc6 Bd5 56.
Nxe5 Kxe5 57. Rh5+ Ke4 58. Rxd5 Kxd5 59. Kh2 Ke5 60. Kh3 Kf5 61. Kh4 { draw
} 1/2-1/2

[Robert Allgeuer]

Geschrieben von:/Posted by: Robert Allgeuer at 09 June 2004 08:54:43:
Als Antwort auf:/In reply to: Re: Possible draw bug in Thinker geschrieben von:/posted by: Rafael Peña at 09 June 2004 00:07:22:

hello!
just a question, why post a bug from a old engine?
Rafael Peña

This is a game of the old version 4.5b of Thinker. It is known that this version does incorrect draw claims; this has been fixed in more recent releases. I nevertheless post this game, because this one may on top of that indicate that the underlying KPK recogniser incorrectly recognises this endgame with g pawn as draw, because in fact this game is lost as opposed to what Thinker thinks.
Robert
[Event "Aristarch 4.50 gauntlet"]
[Site "DISCO"]
[Date "2004.05.28"]
[Round "15.1"]
[White "Aristarch v4.50"]
[Black "Thinker v4.5b"]
[Result "1/2-1/2"]
[TimeControl "300+2"]
[Number "2395"]
1. c4 Nf6 2. Nf3 e6 3. g3 Be7 4. Bg2 d5 5. d4 O-O 6. Qc2 dxc4 7. Qxc4 a6 8.
Bf4 Nd5 9. Bd2 Bd7 10. Nc3 b5 11. Qb3 Bc6 12. O-O Nd7 13. a4 bxa4 14. Nxa4
Bb5 15. Rfe1 c5 16. Nc3 Nxc3 17. Bxc3 Nb6 18. dxc5 Bxc5 19. Red1 Qc7 20.
Be5 Qe7 21. Nd4 Bc4 22. Qc3 f6 23. Nc6 Qb7 24. Bf4 Rac8 25. b4 Bd5 26. bxc5
Bxg2 27. Na5 Qa8 28. Bd6 Rfe8 29. Rab1 Nd5 30. Qc4 Nc7 31. f3 Bh3 32. Qh4
Bf5 33. e4 Bg6 34. Rb7 Nb5 35. e5 Nxd6 36. cxd6 Rb8 37. Qb4 Rxb7 38. Qxb7
Bc2 39. Ra1 fxe5 40. d7 Rd8 41. Qxa8 Rxa8 42. Nb7 Kf7 43. d8=Q Rxd8 44.
Nxd8+ Ke7 45. Nc6+ Kf6 46. Rxa6 g5 47. Ra5 e4 48. f4 h6 49. Nd4 Bd3 50. Re5
Bc4 51. Rxe4 Ba2 52. fxg5+ hxg5 53. h4 gxh4 54. Rxh4 e5 55. Nc6 Bd5 56.
Nxe5 Kxe5 57. Rh5+ Ke4 58. Rxd5 Kxd5 59. Kh2 Ke5 60. Kh3 Kf5 61. Kh4 { draw
} 1/2-1/2

I have explained this, new versions of Thinker do not claim a draw one move too early any longer. Here there is, however, an additional bug, concerning how Thinker evaluates KPK: For Thinker it is a draw, in reality it is a loss. This KPK problem as such was not reported yet, and may still be existent in current Thinkers.
Robert




YABRL (Yet Another Blitz Rating List)

[Lance Perkins]

Geschrieben von:/Posted by: Lance Perkins at 10 June 2004 05:42:56:
Als Antwort auf:/In reply to: Possible draw bug in Thinker geschrieben von:/posted by: Robert Allgeuer at 08 June 2004 22:30:09:

Newer versions (4.6) already fixed the KPk draw claim issue.

This is a game of the old version 4.5b of Thinker. It is known that this version does incorrect draw claims; this has been fixed in more recent releases. I nevertheless post this game, because this one may on top of that indicate that the underlying KPK recogniser incorrectly recognises this endgame with g pawn as draw, because in fact this game is lost as opposed to what Thinker thinks.
Robert
[Event "Aristarch 4.50 gauntlet"]
[Site "DISCO"]
[Date "2004.05.28"]
[Round "15.1"]
[White "Aristarch v4.50"]
[Black "Thinker v4.5b"]
[Result "1/2-1/2"]
[TimeControl "300+2"]
[Number "2395"]
1. c4 Nf6 2. Nf3 e6 3. g3 Be7 4. Bg2 d5 5. d4 O-O 6. Qc2 dxc4 7. Qxc4 a6 8.
Bf4 Nd5 9. Bd2 Bd7 10. Nc3 b5 11. Qb3 Bc6 12. O-O Nd7 13. a4 bxa4 14. Nxa4
Bb5 15. Rfe1 c5 16. Nc3 Nxc3 17. Bxc3 Nb6 18. dxc5 Bxc5 19. Red1 Qc7 20.
Be5 Qe7 21. Nd4 Bc4 22. Qc3 f6 23. Nc6 Qb7 24. Bf4 Rac8 25. b4 Bd5 26. bxc5
Bxg2 27. Na5 Qa8 28. Bd6 Rfe8 29. Rab1 Nd5 30. Qc4 Nc7 31. f3 Bh3 32. Qh4
Bf5 33. e4 Bg6 34. Rb7 Nb5 35. e5 Nxd6 36. cxd6 Rb8 37. Qb4 Rxb7 38. Qxb7
Bc2 39. Ra1 fxe5 40. d7 Rd8 41. Qxa8 Rxa8 42. Nb7 Kf7 43. d8=Q Rxd8 44.
Nxd8+ Ke7 45. Nc6+ Kf6 46. Rxa6 g5 47. Ra5 e4 48. f4 h6 49. Nd4 Bd3 50. Re5
Bc4 51. Rxe4 Ba2 52. fxg5+ hxg5 53. h4 gxh4 54. Rxh4 e5 55. Nc6 Bd5 56.
Nxe5 Kxe5 57. Rh5+ Ke4 58. Rxd5 Kxd5 59. Kh2 Ke5 60. Kh3 Kf5 61. Kh4 { draw
} 1/2-1/2