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Engine puzzle position



 
 
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  #1  
Old July 21st 17, 05:14 PM posted to rec.games.chess.computer,rec.games.chess.analysis
Martin Brown[_2_]
external usenet poster
 
Posts: 3
Default Engine puzzle position

I have stumbled upon a position where quite a few engines - I thought at
first it was just x64 types but Fritz 10 also sees the same phantom
"Good move" which evaluates as a draw where none exists. The position is
hopelessly lost but that isn't the point. Something is wrong.

I found it analysing a lost game where there was a clear and bizarre
discontinuity in the evaluation function that made no sense to me.

Crafty x64 23.05 also sees the wrong right move but x32 20.14 is OK.

r2r4/1p2p1kp/p5p1/3BNbPn/8/2N4P/PPP2P2/R3K2R b KQ - 0 21

It is a close run thing between 22. ... Rac8, or 22 ... Nf4
but the phantom move which evaluates as a draw is 22. ... Bc8

If you actually play this move Bc8 then the evaluation becomes correct
again with white to move. There is something odd about this position
that breaks some engines. Any ideas what it might be?

My guess is that it is some sort of draw by repetition bug common to
several of the engines since the offending thread displays as just a
single move with no continuation line :

354: Deep Fritz 14 - M, Blitz 5m+5s-4m+2s
r2r4/1p2p1kp/p5p1/3BNbPn/8/2N4P/PPP2P2/R3K2R b KQ - 0 1

Analysis by Deep Fritz 14 x64:

1. = (0.00): 21...Bc8
2. +- (4.91): 21...Nf4 22.0-0-0 Nxh3 23.Rdf1 Rac8 24.Bxb7 Rc5 25.f4 Rd4
26.Re1 e6 27.Nd3 Rxd3 28.cxd3 Nxf4 29.Bxa6 Bxd3 30.Rh4 Ng2 31.Rxe6 Bxa6
32.Re7+ Kg8 33.Rhxh7 Rxg5 34.Reg7+ Kf8 35.Rf7+ Kg8 36.Rhg7+ Kh8 37.Ne4
3. +- (4.92): 21...Bxc2 22.Bxb7 Rab8 23.Nc6 Rxb7 24.Nxd8 Rxb2 25.Ne6+
Kf7 26.Nc5 Nf4 27.a4 Bf5 28.Ra2
4. +- (4.92): 21...Rac8 22.0-0-0 Nf4 23.Bf3 Rxd1+ 24.Rxd1 Rc5 25.Re1
Nxh3 26.Bxb7 Nxg5 27.Bxa6 h5 28.Bd3 Nf7 29.Nxf7 Kxf7 30.Kd2 Bxd3 31.Kxd3
Rf5 32.a4 h4 33.Ne4 Rd5+ 34.Ke3 Ra5 35.Rh1 Rxa4 36.Rxh4
5. +- (5.18): 21...Rab8 22.0-0-0 Nf4 23.h4 Rbc8 24.Bf3 b5 25.Rxd8 Rxd8
26.Nc6 Re8 27.Rd1 Nh3 28.Rd2
6. +- (5.34): 21...Ra7 22.0-0-0 Nf4 23.h4 Rc8
7. +- (5.37): 21...e6 22.Bxb7 Rab8 23.Nc6 Rxb7 24.Nxd8 Rxb2
8. +- (5.60): 21...Rf8 22.0-0-0 Ra7 23.Rd4 Bc8 24.Re1 b5 25.Nd3 Bxh3
26.Rde4 e6 27.Bxe6 Bg2 28.Rd4 Re7 29.Rd7 Rxd7 30.Bxd7 Ba8 31.Re6 Bb7
32.Rb6 Rb8 33.Nd5

(, 21.07.2017)

And after playing the supposedly drawing move it is obviously junk:

354: Deep Fritz 14 - M, Blitz 5m+5s-4m+2s
r1br4/1p2p1kp/p5p1/3BN1Pn/8/2N4P/PPP2P2/R3K2R w KQ - 0 1

Analysis by Deep Fritz 14 x64:

1. +- (5.69): 22.0-0-0 Ra7 23.h4 Nf4 24.Bb3 Re8 25.Rd4 Nh3 26.f4 Nf2
27.Rg1 Bf5 28.Rg2 Nh3 29.Rgd2 b5 30.Nd5 Rf8 31.Nc6 Rd7 32.Ndxe7
2. +- (5.59): 22.h4 Re8 23.0-0-0 Nf4 24.Rhe1 Rb8 25.Be4 Rf8 26.Nd7
3. +- (5.34): 22.a4 Ra7 23.0-0-0 Rf8 24.Rhe1 Bxh3 25.Nd7 Re8 26.Nf6
Nxf6 27.gxf6+ Kxf6
4. +- (5.20): 22.Nc4 Nf4 23.0-0-0 Rb8 24.Rhe1 e6 25.Bf3 Rxd1+ 26.Rxd1
Nxh3 27.Ne4 b5 28.Ne5 b4 29.Rd8 Rb5 30.Ng4 Bb7 31.Rd7+ Kh8 32.Ngf6 Bxe4
33.Rxh7#
5. +- (5.17): 22.Nd3 Rf8 23.0-0-0 Ra7 24.Rhe1 b5 25.Be6 Bxe6 26.Rxe6
Nf4 27.Nxf4 Rxf4 28.Rde1 Kf8 29.Ne4 a5 30.Rb6 Rf5 31.Rc6 Rd7 32.Nc5 Rdd5
33.Rc8+ Kf7
6. +- (5.09): 22.a3 Ra7 23.0-0-0 Rf8 24.Rhe1 b5 25.h4 Rc7 26.Bf3 Nf4
27.Kb1 Bf5 28.Be4 Bxe4 29.Rxe4 e6 30.Red4 Nd5 31.Ne4
7. +- (5.03): 22.b3 Rf8 23.0-0-0 Ra7 24.Nd3 Nf4 25.Nxf4 Rxf4 26.f3 Rh4
27.Rde1 b5 28.Be6 Bb7 29.Ne4 Ra8 30.Kb2 Rd8 31.Rhg1 b4
8. +- (4.96): 22.Rh2 Nf4 23.0-0-0 a5 24.Rd4 Nxh3 25.Rh4 Nxg5 26.f4 Nh3
27.Bg2 g5 28.R4xh3 Bxh3 29.Rxh3 gxf4 30.Bxb7 Rab8 31.Be4 h6 32.Nc6

(, 21.07.2017)

Some engines can see as far as 0-0-0 from the ply before but the ones
that fail still seem convinced it is a draw with no analysis given.

I'm running under Deep fritz 14 user interface but most of the engines I
have tried so far fail on this position. Crafty x32 a notable exception.

Can anyone shed any light on what is going on?

Is there anyone still reading these groups? - it's awfully quiet...

--
Regards,
Martin Brown
  #2  
Old July 21st 17, 10:23 PM posted to rec.games.chess.computer,rec.games.chess.analysis
Rainer[_2_]
external usenet poster
 
Posts: 29
Default Engine puzzle position

On 21/07/2017 17:14, Martin Brown wrote:

I have stumbled upon a position where quite a few engines - I thought
at first it was just x64 types but Fritz 10 also sees the same
phantom "Good move" which evaluates as a draw where none exists. The
position is hopelessly lost but that isn't the point. Something is
wrong.

I found it analysing a lost game where there was a clear and bizarre
discontinuity in the evaluation function that made no sense to me.

Crafty x64 23.05 also sees the wrong right move but x32 20.14 is OK.

r2r4/1p2p1kp/p5p1/3BNbPn/8/2N4P/PPP2P2/R3K2R b KQ - 0 21

It is a close run thing between 22. ... Rac8, or 22 ... Nf4 but the
phantom move which evaluates as a draw is 22. ... Bc8

If you actually play this move Bc8 then the evaluation becomes
correct again with white to move. There is something odd about this
position that breaks some engines. Any ideas what it might be?

My guess is that it is some sort of draw by repetition bug common to
several of the engines since the offending thread displays as just a
single move with no continuation line : [...]


You didn't post the game, so I have to ask: is there a position
repetition after 21...Bc8? If so, a zero score would be acceptable.

Cheers,
Rainer
  #3  
Old July 22nd 17, 10:16 AM posted to rec.games.chess.computer,rec.games.chess.analysis
Martin Brown[_2_]
external usenet poster
 
Posts: 3
Default Engine puzzle position

On 21/07/2017 21:23, Rainer wrote:
On 21/07/2017 17:14, Martin Brown wrote:

I have stumbled upon a position where quite a few engines - I thought
at first it was just x64 types but Fritz 10 also sees the same
phantom "Good move" which evaluates as a draw where none exists. The
position is hopelessly lost but that isn't the point. Something is
wrong.

I found it analysing a lost game where there was a clear and bizarre
discontinuity in the evaluation function that made no sense to me.

Crafty x64 23.05 also sees the wrong right move but x32 20.14 is OK.

r2r4/1p2p1kp/p5p1/3BNbPn/8/2N4P/PPP2P2/R3K2R b KQ - 0 21

It is a close run thing between 22. ... Rac8, or 22 ... Nf4 but the
phantom move which evaluates as a draw is 22. ... Bc8

If you actually play this move Bc8 then the evaluation becomes
correct again with white to move. There is something odd about this
position that breaks some engines. Any ideas what it might be?

My guess is that it is some sort of draw by repetition bug common to
several of the engines since the offending thread displays as just a
single move with no continuation line : [...]


You didn't post the game, so I have to ask: is there a position
repetition after 21...Bc8? If so, a zero score would be acceptable.


The material balance is such that the winning side should not be looking
for a draw and the losing side has no way to force perpetual check. The
score for the move 22. ... Bc8 is totally anomolous (as is the fact that
it does not have any continuation line in the annotation).

It might be relevant that the strongest continuation for white is 0-0-0
and there may be a bug in the logic around queens side castling
somewhere. Almost none of the engines see anything other than "best" is
21. ... Bc8 0.0 (and see no further than that)

This is the result of applying blundercheck threshold 20cp 4s to the
entire game (opening blunder in blitz) but played on in the hope of
winning something back.

[Event "Blitz 5m+5s-4m+2s"]
[Site "?"]
[Date "2017.07.21"]
[Round "?"]
[White "Deep Fritz 14"]
[Black "Martin"]
[Result "1-0"]
[ECO "B08"]
[WhiteElo "1812"]
[BlackElo "1815"]
[PlyCount "75"]
[TimeControl "240+2"]

1. d4 {0} d6 {4}
2. e4 {0} Nf6 {2}
3. Bd3 {0} g6 {2}
4. Nf3 {0} Bg7 {1}
5. h3 {0.23/20 0 last book move} Nbd7 {0.20/18 2}
6. Nc3 {0.20/21 0} O-O {0.20/20 1}
7. e5 {0.20/20 0} dxe5 {0.47/21 6}
({Deep Fritz 14 x64:} 7... Ne8 8. Qe2 c5 9. Bg5 cxd4 10. exd6 Nxd6 11.
Bxe7 Qb6 12. Bxf8 Nxf8 13. Ne4 Nxe4 14. Bxe4 Qb4+15. Nd2 Qxb2 16. O-O
Ne6 17. Rab1 Qxa2 18. Bxb7 Bxb7 19. Rxb7 Qxc2 20. Qf3 Rf821. Rd1 a5
{0.20/20})
8. dxe5 {0.38/21 0} Nh5 {1.02/18 8}
({Deep Fritz 14 x64:} 8... Ne8 9. Bc4 {0.38/21})
9. g4 {0.89/18 0} Nf4 {3.61/20 7}
({Deep Fritz 14 x64:} 9... Nxe5 10. gxh5 Nxd3+ 11. Qxd3 Bf5 12. Qe2 Qd6
13. O-O Bxh3 14. Re1 Bxc3 15. bxc3 Qd5 16. h6 Rfd8 17. Rb1 b6 18. c4 Qf5
19. Qe5 Qxe5 20. Nxe5 Bf5 21. Nc6 {0.89/18})
10. Bxf4 {3.50/19 0} f6 {4.26/19 23}
({Deep Fritz 14 x64:} 10... Nc5 11. Be2 Ne6 12. Be3 Bd7 13. Qd2 Bc6 14.
O-O-O Qxd2+ 15. Bxd2 Rad8 16. Be3 b6 17. Rxd8 Rxd8 18. Rd1 Rxd1+ 19.
Bxd1 Bxf3 20. Bxf3 Bxe5 21. Kd2 Bf4 22. Nb5 Bxe3+ 23. fxe3 a6 {3.50/19})
11. exf6 {4.16/18 0} Nxf6 {5.42/22 2}
({Deep Fritz 14 x64:} 11... exf6 12. Bc4+ Kh8 13. O-O f5 14. g5 Qe7 15.
Bb3 Nc5 16. Nd5 Qe4 17. Re1 {4.16/18})
12. Bc4+ {5.42/22 0} Kh8 {5.42/21 2}
13. Qxd8 {5.42/21 0} Rxd8 {5.29/20 3 Deep Fritz 14 doubles}
14. Bxc7 {5.27/19 0} Rd7 {6.15/20 6}
15. Be5 {5.94/19 0} a6 {6.29/19 10}
16. g5 {5.44/19 0} Nh5 {5.49/20 4}
17. Be6 {5.20/22 0} Rd8 {5.20/21 5}
18. Bd5 {5.12/19 0} Bxe5 {5.65/21 34}
19. Nxe5{5.47/19 0} Kg7 {5.70/19 19}
20. Bb3 {4.74/19 0} Bf5 {4.74/18 16}
21. Bd5 {0.00/28 0} ({Deep Fritz 14 x64:} 21. Ne2 Rd6 {4.74/18})
21... Rab8 {5.18/19 6} ({Deep Fritz 14 x64:} 21... Bc8 {0.00/28})
22. a4 {3.15/19 0}
({Deep Fritz 14 x64:} 22. O-O-O Nf4 23. h4 Rbc8 24. Bf3 Rd6 25. Rhe1
Rxd1+ 26. Rxd1 Rc7 27. Rd4 Nh3 28. Be4 Nxf2 29. Bxf5 gxf5 30. Rf4 Rxc3
31. bxc3 {5.18/19})
22... e6 {4.24/22 8}
({Deep Fritz 14 x64:} 22... Bxc2 23. Bf3 Nf4 24. Ne2 Nd3+ 25. Nxd3 Bxd3
26. Rc1 b5 27. a5 Bc4 28. Rc3 Rbc8 29. b3 Be6 30. Re3 Rd6 31. Nf4 Rc1+
32. Ke2 Rc2+ 33. Kf1 {3.15/19})
23. Be4 {4.24/21 0} Nf4 {4.24/19 21}
24. Rc1 {3.96/18 0} Rd4 {4.59/22 13}
25. Bxf5 {4.50/21 0} exf5 {4.50/21 3}
26. Rd1 {4.48/19 0} Rb4 {5.68/19 13}
({Deep Fritz 14 x64:} 26... Rdd8 27. Nd3 Ne6 28. h4 Nd4 29.Kd2 b5 30.
axb5 axb5 31. Ne2 Ra8 32. Nxd4 Rxd4 33. Ra1 {4.48/19})
27. Rd7+ {5.68/19 0} Kg8 {5.59/17 7}
28. Nd5 {4.10/18 0}
({Deep Fritz 14 x64:} 28. Kd2 Rxb2 29. Re1 Nxh3 30. Nd3 Nxg5
31. Nxb2 Nf3+ 32. Ke2 Nxe1 33. Kxe1 Re8+ 34. Kf1 b6 35. Nd5 Re6
36. Nd3 b5 37. Nc5 {5.59/17})
28... Re4+ {5.45/21 9}
({Deep Fritz 14 x64:} 28... Nxd5 29. Rxd5 Rxb2 30. Nd7 Re8+ 31. Kd2 Rc8
32. Nf6+ Kh8 33. Rc1 {4.10/18})
29. Kf1 {5.28/18 0} Rxe5 {6.33/20 8}
30. Nxf4 {6.14/19 0} Re4 {7.97/20 10}
({Deep Fritz 14 x64:} 30... b5 31. Nd3 Re4 32. axb5 axb5 33. Kg2 Rbe8
34. Ra1 R8e7 35. Ra8+ Kg7 36. Rxe7+ Rxe7 37. Rb8 Re2 38. Rb7+ Kg8 39.
Nb4 Re5 40. Kf3 Rc5 41. c3 Re5 42. Nc6 Re6 43. Nd4 {6.14/19})
31. Nd5 {7.77/20 0} Rxa4 {13.94/20 3}
({Deep Fritz 14 x64:} 31... Kf8 32. Kg2 {7.77/20})
32. Nf6+ {13.53/20 0} Kf8 {12.20/18 5}
33. Rxh7 {8.61/18 0}
({Deep Fritz 14 x64:} 33. Nxh7+ Kg8 34. Nf6+ Kf8 35. Kg2 Rc8 36. Re1 Re4
37. Nxe4 fxe4 38. Rxb7 Rc4 39. Rd1 Rc8 40. Rd6 e3 41. fxe3 a5 42. Rf6+
Kg8 43. Rxg6+ Kf8 44. Rf6+ Kg8 45. c3 Rc5 46. h4 Rd5 47. Ra6 Rd2+ 48.
Kf3 {12.20/18})
33... Rd8 {12.54/21 13}
({Deep Fritz 14 x64:} 33... Ra1+ 34. Kg2 Rxh1 35. Rh8+ Kf7 36. Rxb8 Ra1
37. Rxb7+ Ke6 38. Rb6+ Kf7 39. c4 a5 40. c5 Rc1 41. c6 a4 42. Nd5 Ke6
43. Nf4+ Kd6 44. Nxg6 Kc5 45. Rb8 Kd6 46. h4 Rxc6 47. h5 Rc4 48. Rd8+
Ke6 49. Re8+ {8.61/18})
34. Kg2 {11.99/19 0} Rd2 {17.14/23 10}
({Deep Fritz 14 x64:} 34... Rd6 35. Re1 Re4 36.Nxe4 fxe4 37. Rxb7 Rd4
38. Rb6 Kg7 39. Rxa6 Rd5 40. Ra7+ Kf8 41. Rxe4 Rxg5+ 42.Rg4 Rb5 43. Rc4
Rb8 44. Rcc7 Kg8 45. b3 Rd8 46. h4 Kf8 47. Ra6 Ke8 48. Rxg6 Kf8
49. h5 Rd2 50. Rgg7 {11.99/19})
35. Re1 {17.05/21 0} Re4 {15.24/23 7}
36. Nxe4 {14.68/22 0} fxe4 {14.28/21 2}
37. Rxb7 {12.59/18 0} e3 {21.93/23 6}
({Deep Fritz 14 x64:} 37... Rd4 38. Rb6 Kf7 39. Rf6+ Kg7 40. Rxa6 Rd5
41. Rxe4 Rb5 42. Ra7+ Kf8 43. b3 Rxg5+ 44. Rg4 Rd5 45. Rxg6 Rd8 46. c4
Rb8 47. Rf6+ Kg8 48. Rd6 Kf8 49. c5 Rc8 50. c6 Ke8 51. Rg6 {12.59/18})
38. Rxe3 {19.94/20 0} 1-0


Just in case it is relevant Deep Fritz is running on a 4 core i7 3770K
but the other failing chess engines are mostly single core ones.

--
Regards,
Martin Brown
  #4  
Old July 22nd 17, 01:46 PM posted to rec.games.chess.computer,rec.games.chess.analysis
Rainer[_2_]
external usenet poster
 
Posts: 29
Default Engine puzzle position

On 22/07/2017 10:16, Martin Brown wrote:
On 21/07/2017 21:23, Rainer wrote:
On 21/07/2017 17:14, Martin Brown wrote:

I have stumbled upon a position where quite a few engines - I
thought at first it was just x64 types but Fritz 10 also sees
the same phantom "Good move" which evaluates as a draw where
none exists. The position is hopelessly lost but that isn't the
point. Something is wrong.

I found it analysing a lost game where there was a clear and
bizarre discontinuity in the evaluation function that made no
sense to me.

Crafty x64 23.05 also sees the wrong right move but x32 20.14 is
OK.

r2r4/1p2p1kp/p5p1/3BNbPn/8/2N4P/PPP2P2/R3K2R b KQ - 0 21

It is a close run thing between 22. ... Rac8, or 22 ... Nf4 but
the phantom move which evaluates as a draw is 22. ... Bc8

If you actually play this move Bc8 then the evaluation becomes
correct again with white to move. There is something odd about
this position that breaks some engines. Any ideas what it might
be?

My guess is that it is some sort of draw by repetition bug
common to several of the engines since the offending thread
displays as just a single move with no continuation line : [...]


You didn't post the game, so I have to ask: is there a position
repetition after 21...Bc8? If so, a zero score would be
acceptable.


The material balance is such that the winning side should not be
looking for a draw and the losing side has no way to force perpetual
check. The score for the move 22. ... Bc8 is totally anomolous (as
is the fact that it does not have any continuation line in the
annotation).

It might be relevant that the strongest continuation for white is
0-0-0 and there may be a bug in the logic around queens side
castling somewhere. Almost none of the engines see anything other
than "best" is 21. ... Bc8 0.0 (and see no further than that)

This is the result of applying blundercheck threshold 20cp 4s to the
entire game (opening blunder in blitz) but played on in the hope of
winning something back.
[...]


[game score weeded]

[Event "Blitz 5m+5s-4m+2s"]
[Site "?"]
[Date "2017.07.21"]
[Round "?"]
[White "Deep Fritz 14"]
[Black "Martin"]
[Result "1-0"]
[ECO "B08"]
[WhiteElo "1812"]
[BlackElo "1815"]
[PlyCount "75"]
[EventDate "2017.??.??"]
[EventType "blitz"]

1. d4 d6 2. e4 Nf6 3. Bd3 g6 4. Nf3 Bg7 5. h3 Nbd7 6. Nc3 O-O 7. e5 dxe5
8. dxe5 Nh5 9. g4 Nf4 10. Bxf4 f6 11. exf6 Nxf6 12. Bc4+ Kh8 13. Qxd8
Rxd8 14. Bxc7 Rd7 15. Be5 a6 16. g5 Nh5 17. Be6 Rd8 18. Bd5 Bxe5 19.
Nxe5 Kg7 {1st occurrence} 20. Bb3 Bf5 21. Bd5 Rab8 (21... Bc8 {position
repetition}) 22. a4 e6 23. Be4 Nf4 24. Rc1 Rd4 25. Bxf5 exf5 26. Rd1 Rb4
27. Rd7+ Kg8 28. Nd5 Re4+ 29. Kf1 Rxe5 30. Nxf4 Re4 31. Nd5 Rxa4 32.
Nf6+ Kf8 33. Rxh7 Rd8 34. Kg2 Rd2 35. Re1 Re4 36. Nxe4 fxe4 37. Rxb7 e3
38. Rxe3 1-0

It's what I suspected: 21...Bc8 repeats the position, hence the draw
score. UCI engines are always fed with the full game history, so they
can detect the repetition.

NB: there is a decades-old controversy whether it's ok to return a draw
score after the first position repetition, or if this should be done
only after the second repetition. One can argue either way, I'll let
that aside.

Cheeers,
Rainer
  #5  
Old August 27th 17, 06:31 AM posted to rec.games.chess.computer,rec.games.chess.analysis
Marc Moisan
external usenet poster
 
Posts: 1
Default Engine puzzle position

On 2017-07-22 04:46, Rainer wrote:

NB: there is a decades-old controversy whether it's ok to return a draw
score after the first position repetition, or if this should be done
only after the second repetition. One can argue either way, I'll let
that aside.


The relevant rule in the FIDE laws of chess is 9.2, which reads:

The game is drawn, upon a correct claim by the player having the
move, when the same position, for at least the third time (not
necessarily by sequential repetition of moves)

a. is about to appear, if he first writes his move on his
scoresheet and declares to the arbiter his intention to make this move, or

b. has just appeared, and the player claiming the draw has the move.

In other words the position ought to occur (about to or just did) for
the third time, but in addition must also be so claimed by the player
having the move. It is not an automatic draw (although most programs
make it an automatic draw).

Cheers,

Marc Moisan, CD, PLog

  #6  
Old August 29th 17, 11:07 AM posted to rec.games.chess.computer,rec.games.chess.analysis
Martin Brown[_2_]
external usenet poster
 
Posts: 3
Default Engine puzzle position

On 27/08/2017 05:31, Marc Moisan wrote:
On 2017-07-22 04:46, Rainer wrote:

NB: there is a decades-old controversy whether it's ok to return a draw
score after the first position repetition, or if this should be done
only after the second repetition. One can argue either way, I'll let
that aside.


The relevant rule in the FIDE laws of chess is 9.2, which reads:

The game is drawn, upon a correct claim by the player having the
move, when the same position, for at least the third time (not
necessarily by sequential repetition of moves)

a. is about to appear, if he first writes his move on his
scoresheet and declares to the arbiter his intention to make this move, or

b. has just appeared, and the player claiming the draw has the move.

In other words the position ought to occur (about to or just did) for
the third time, but in addition must also be so claimed by the player
having the move. It is not an automatic draw (although most programs
make it an automatic draw).


We know what the FIDE rules are. The problem here is that for reasons of
computational convenience these engines return a draw as the evaluation
on the first repetition of a position even when it is clearly lost.
Worse it makes the same mistake when analysing/annotating a played game.

I can see why it might cut some corners in game play.

I have also noticed that the UI for Deep Fritz 14 makes a considerable
number of errors in distance to mate calculations during blunder checks
that were correct in earlier versions of the software.

--
Regards,
Martin Brown
 




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