Error in GnuChess?

[Leen Ammeraal]

Hello,
Up to now, I have always regarded GnuChess as
a very fine chess engine of formidable strength.
However, in the following game, it claimed a
draw for no apparent reason. Is this a well-known
bug? It looks like an error in the code that should
recognize 3-fold repetition.
I used the version that comes with the
latest version of WinBoard.

[Event "Computer chess game"]
[Site "O4D9F1"]
[Date "2001.05.01"]
[Round "6"]
[White "gnuchess"]
[Black "wbqueen"]
[Result "1/2-1/2"]
[TimeControl "20+4"]
1. Nf3 Nf6 2. c4 g6 3. g3 Bg7 4. Bg2 O-O 5. O-O d6 6. d4 Nbd7 7. Nc3 Nb6 8.
b3 Bg4 9. Qd3 Qd7 10. Bd2 Bf5 11. e4 Bh3 12. Rfd1 a5 13. Bxh3 Qxh3 14. Qf1
Qg4 15. Qe2 Rfd8 16. Bf4 Nh5 17. Ng5 Qxe2 18. Nxe2 Nxf4 19. gxf4 a4 20. f3
h6 21. Nh3 c5 22. Rab1 axb3 23. axb3 cxd4 24. Nxd4 Ra2 25. Nf2 Rda8 26. Ng4
h5 27. Nf2 Nd7 28. Nb5 Nc5 29. Nd3 Ne6 30. e5 dxe5 31. fxe5 Ng5 32. Nd4 Rd8
33. Nb4 Nh3+ 34. Kf1 Rxh2 35. Nd5 Bxe5 36. Nb5 Kf8 37. Ndc3 Rc8 38. Nd4 h4
39. Nce2 Rh1+ 40. Kg2 Rh2+ 41. Kf1 Bd6 42. Nc2 Rc5 43. Ne3 Rf2+ 44. Ke1 Re5
45. Rd3 Bc5 46. Ra1 Bxe3 47. Ra8+ Kg7 48. Rd5 Rxd5 49. cxd5 Rxf3 50. Ra4
Bf2+ 51. Kf1 Bc5+ 52. Ke1 Rxb3 53. Rc4 Bf2+ 54. Kf1 b6 55. Kg2 f6 56. Nc3
Be1 57. Ne2 Re3 58. Kf1 Bf2 59. Nd4 Rg3 60. Ne6+ Kf7 61. Nd8+ Kg8 62. Ne6
g5 63. Rc7 Rd3 64. Rxe7 Rxd5 65. Rc7
{Draw} 1/2-1/2

By the way, I am the author of Queen, GnuChess's opponent in the above game.
In the past Queen was almost always beaten by GnuChess, but I am very proud
of the latest version of Queen being about as strong as GnuChess. Queen, and
its
WinBoard version, wbQueen, can be downloaded from my website.

Leen Ammeraal
http://home.wxs.nl/~ammeraal/