On Apr 20, 10:53 am, David Richerby
wrote:
Taylor Kingston wrote:

David Richerby wrote:
In the fifth game of the Lasker-Capablanca World Championship match
(1921), the same position[1] occurs after Black's 34th, 36th and
38th moves but the draw was not claimed and Black went on to lose.
Does anyone know why?

An interesting point, Dave. In his annotations to the match,
Capablanca does not even mention the repetition.

I'd be interested to know if any commentators have mentioned it. As I
said, Kasparov also says nothing about it. I guess this isn't one of
the games he analyzed with Fritz: I `found' the repetition when going
through the game using Fritz as a board and it informed me the
position was drawn. My initial thought was that I'd been careless and
turned a two-fold repetition into three-fold.

It would have been up to Lasker, as the player making the move that
creates the third iteration, to claim the draw before making his
38th move. It is possible that he failed to notice threefold
repetition, but it seems unlikely, since the repetitions occur in
direct sequence.

True. On the other hand, the moves that bring about the repeated
position are a pawn move and two king moves -- maybe that threw him
off.

I would suggest that perhaps he chose not to claim the draw, because
he believed he had winning chances.

That's also a possibility, with Capablanca miscalculating. Does Capa
usually come across as being fairly honest in his annotations?

I am certainly not aware of any deliberate dishonesty in any
Capablanca annotations I have ever read.

Do we
infer that he probably wasn't aware of the possibility of Lasker's
claiming the draw when he wrote the notes?

I find it hard to believe that someone of Capa's chess ability would
not notice it. I would therefore tend to think he simply chose not to
mention it, perhaps not considering it relevant.
Interestingly, I recently came across another instance of a missed
draw opportunity, in Lasker-Blackburne, 10th match game, London, 1892:

1. d4 d5 2. Nf3 Nf6 3. c4 e6 4. Nc3 Nbd7 5. Bf4 c6 6. e3 Nh5 7. Bg5
Be7 8. Bxe7
Qxe7 9. Bd3 g6 10. Qe2 O-O 11. O-O f5 12. Rfd1 Ndf6 13. Rac1 Bd7 14.
Ne5 Be8
15. Qc2 Rd8 16. a3 Nd7 17. Nf3 Ng7 18. Re1 Nf6 19. b4 Ne4 20. Ne5 Nxc3
21. Qxc3
Nh5 22. a4 Nf6 23. b5 Nd7 24. Nf3 dxc4 25. Qxc4 Nb6 26. Qb3 cxb5 27.
axb5 Bf7
28. Ne5 Rc8 29. Ra1 Ra8 30. Re2 Rfc8 31. Rea2 Qc7 32. g3 Qc3 33. Qxc3
Rxc3 34.
Rxa7 Rxa7 35. Rxa7 Rc7 36. Kf1 Be8 37. Ke2 Kf8 38. Kd2 Ke7 39. Ra3 Kd6
40. f3
Rc8 41. e4 Rc7 42. Ra1 Rc8 43. h4 Rc7 44. Rb1 Rc8 45. Ke3 Ke7 46. h5
Kf6 47.
hxg6 hxg6 48. Rh1 Kg7 49. Ra1 Ra8 50. Rc1 Rc8 51. Rb1 Kf6 52. Rh1 Kg7
53. Ra1
Ra8 54. Rh1 Rc8 55. g4 fxg4 56. fxg4 Ra8 57. g5 Ra3 58. Kd2 Ra2+ 59.
Ke3 Ra3
60. Kf4 Nd7 61. Bc4 Nf8 62. Rc1 Ra5 63. Bd3 Bxb5 64. Rc5 Ra4 65. Bxb5
Rxd4 66.
Rc7+ Kg8 67. Rxb7 1-0

Black's 54th move repeats the position after his 48th and 52nd
moves. It seems unlikely Blackburne felt himself to be winning; at
that point he's a pawn down and on the defensive. Either he missed the
threefold (it's a bit harder to see than in the Capablanca game), or
perhaps he just figured "What the hell" (he was down +0 -5 =3 in the
match at the time).
The most interesting case of threefold repetition I can recall was
in Fischer-Petrosian, 1971 Candidates Final, 3rd game. Petrosian had
the better of it, but his 33rd move allowed Fischer a move that
repeated the position after White's 30th and 32nd moves; Fischer
immediately claimed the draw. Petrosian may have missed this because
his 29th, 31st, and 33rd moves were all by different pieces, rather
than shuttling the same piece back and forth:

1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 dxe4 5.Nxe4 Be7 6. Bxf6 gxf6 7. g3
f5 8. Nc3 Bf6 9. Nge2 Nc6 10. d5 exd5 11. Nxd5 Bxb2 12. Bg2 O-O 13. O-
O Bh8 14. Nef4 Ne5 15. Qh5 Ng6 16. Rad1 c6 17. Ne3 Qf6 18. Kh1 Bg7 19.
Bh3 Ne7 20. Rd3 Be6 21. Rfd1 Bh6 22. Rd4 Bxf4 23. Rxf4 Rad8 24. Rxd8
Rxd8 25. Bxf5 Nxf5 26. Nxf5 Rd5 27. g4 Bxf5 28. gxf5 h6 29. h3 Kh7 30.
Qe2 Qe5 31. Qh5 Qf6 32. Qe2 Re5 33. Qd3 Rd5 34. Qe2 1/2-1/2