Need help solving a possible case of cheating

[Olivier Deville]

Dear friends,

As you may know, I gave up computer chess to dedicate myself to chess for the blind. I organize tournaments on Skype, and they are becoming more and more popular.

I suspect one of the participants of cheating. His behaviour is quite strange : he starts playing very good chess, and at some point offers draw, or even throws the game away, letting the opponent mate him for instance.

Here is one of the games (he was playing white) :

1. e4 c5 2. c3 d5 3. exd5 Qxd5 4. d4 g6 5. dxc5 Qxc5 6. Nf3 Bg7 7. Be3 Qc7 8.
Bd3 Nf6 9. Na3 a6 10. O-O O-O 11. Nc4 Nbd7 12. Bd4 b5 13. Nce5 Bb7 14. Re1 Rad8
15. a4 bxa4 16. Qxa4 Nc5 17. Bxc5 Qxc5 18. Bxa6 Bd5 19. c4 Bxf3 20. Nxf3 Ng4
21. Re2 Rd3 22. h3 Ne5 23. Nxe5 1/2-1/2

18.Bxa6 was played a tempo, which is not very natural.

Obviously, Houdini and friends are not involved, it must be some weaker engine. Who would be willing to do a search on this case?

Best regards,

[bob]

Dear friends,

As you may know, I gave up computer chess to dedicate myself to chess for the blind. I organize tournaments on Skype, and they are becoming more and more popular.

I suspect one of the participants of cheating. His behaviour is quite strange : he starts playing very good chess, and at some point offers draw, or even throws the game away, letting the opponent mate him for instance.

Here is one of the games (he was playing white) :

1. e4 c5 2. c3 d5 3. exd5 Qxd5 4. d4 g6 5. dxc5 Qxc5 6. Nf3 Bg7 7. Be3 Qc7 8.
Bd3 Nf6 9. Na3 a6 10. O-O O-O 11. Nc4 Nbd7 12. Bd4 b5 13. Nce5 Bb7 14. Re1 Rad8
15. a4 bxa4 16. Qxa4 Nc5 17. Bxc5 Qxc5 18. Bxa6 Bd5 19. c4 Bxf3 20. Nxf3 Ng4
21. Re2 Rd3 22. h3 Ne5 23. Nxe5 1/2-1/2

18.Bxa6 was played a tempo, which is not very natural.

Obviously, Houdini and friends are not involved, it must be some weaker engine. Who would be willing to do a search on this case?

Best regards,

There are various forms of cheating. Including using a computer but occasionally making an intentional blunder to make it more difficult to detect...

[Norm Pollock]

Could be losing to a sockpuppet.

[skoony]

could be using a good book on openings.
once he's out of the book he's lost as what to do.

regards
mike

[kgburcham]

18.Bxa6 was played a tempo, which is not very natural.

First of all, I do not understand the post.
Did you mean to say Bxa6 loses a tempo?
I tried 4 programs and each plays 18.Bxa6 at a shallow depth.
Why isn't this move "a natural" human move if a human can quickly see black loses a pawn without compensation?
I do not see any immediate threats from black to prevent capturing the pawn, do you?
Notice the eval below in multi pv: which move is more "natural" for a human?
The programs show 18.Bxa6 as best move.

Obviously, Houdini and friends are not involved, it must be some weaker engine.

what does this mean? I do not understand why you said this.
all the programs I tried choose Bxa6.

Oh well
best to you,
kgburcham

[D] 3r1rk1/1b2ppbp/p4np1/2q1N3/Q7/2PB1N2/1P3PPP/R3R1K1 w - -


30 5:36 +0.90 18.Bxa6 Bxf3 19.Nxf3 Nd5 20.Bf1 Rb8 21.Ra2 e6 22.g3 Rfc8 23.Rea1 Qd6 24.Qh4 Rd8 25.Qe4 Bf6 26.Bc4 Qc5 27.Ra5 Qb6 (3.584.792.604) 10647
30 5:36 +0.54 18.Bc4 Bxf3 19.Nxf3 a5 20.Qb5 Qc7 21.Rxa5 Rb8 22.Qc5 Qxc5 23.Rxc5 Rxb2 24.Rxe7 Rb1+ 25.Re1 Rxe1+ 26.Nxe1 Ne4 27.Rc7 Bxc3 28.Nd3 Kg7 29.Bd5 Ba5 30.Ra7 Bb6 31.Rb7 (3.584.792.604) 10647
29 5:36 0.00 18.Bf1 Rd6 19.Nd4 Qc7 20.Qa5 Qb8 21.Qb4 e6 22.Nb3 Nd5 23.Qa3 Nb6 24.g3 Rd5 25.Nd3 Nc4 (3.584.792.604) 10647
29 5:36 0.00 18.Qa5 Qxa5 19.Rxa5 Rd6 20.Bf1 e6 21.Nc4 Rd5 22.Rxd5 Bxd5 23.Nfe5 Rb8 24.N(3.584.792.604) 10647

Houdini

18/40 0:01 +0.67 18.Bxa6 Bxf3 (18.097.273) 15233
19/40 0:01 +0.72 18.Bxa6 Bxf3 (31.490.061) 15816
20/47 0:06 +0.75 18.Bxa6 Bxf3 19.Nxf3 Nd5 20.Bf1 Rb8 21.Ra2 e6 22.Qc4 Qd6 23.g3 Rfd8 (98.412.897) 16344
21/47 0:07 +0.71 18.Bxa6 Bxf3 19.Nxf3 Nd5 20.Bf1 Rb8 21.Ra2 e6 22.g3 Rfc8 (122.791.194) 16422
22/51 0:13 +0.71 18.Bxa6 Bxf3 19.Nxf3 Nd5 (221.067.369) 16746
23/54 0:27 +0.75 18.Bxa6 Bxf3 19.Nxf3 Nd5 20.Bf1 Rb8 21.Ra2 Rfc8 22.Qa6 e6 23.g3 Rd8 (461.233.184) 16816
24/54 0:32 +0.75 18.Bxa6 Bxf3 19.Nxf3 Nd5 (550.232.691) 16941
25/54 0:44 +0.74 18.Bxa6 Bxf3 19.Nxf3 Nd5 20.Bf1 Rb8 21.Ra2 Rfc8 22.Qa6 e6 23.g3 Rd8 24.Rea1 Qe7 (767.395.659) 17092
26/57 1:17 +0.74 18.Bxa6 Bxf3 19.Nxf3 Nd5 (1.337.156.800) 17295
27/71 3:21 +0.64-- 18.Bxa6 Bd5 (3.532.515.857) 17508
27/71 4:23 +0.74 18.Bxa6 Bxf3 19.Nxf3 Nd5 20.Bf1 Rb8 21.Ra2 e6 22.g3 Rfc8 23.Qa6 Rd8 24.Rea1 Qe7 25.Qa4 Qd6 26.Qh4 Qb6 27.Rd1 Qb3 28.Qa4 Qb7 29.Qa7 Qb3 30.Rd2 Bh6 31.Ra3 (4.623.973.628) 17535


1. e4 c5 2. c3 d5 3. exd5 Qxd5 4. d4 g6 5. dxc5 Qxc5 6. Nf3
Bg7 7. Be3 Qc7 8. Bd3 Nf6 9. Na3 a6 10. O-O O-O 11. Nc4
Nbd7 12. Bd4 b5 13. Nce5 Bb7 14. Re1 Rad8 15. a4 bxa4
16. Qxa4 Nc5 17. Bxc5 Qxc5 18. Bxa6 Bd5 19. c4 Bxf3
20. Nxf3 Ng4 21. Re2 Rd3 22. h3 Ne5 23. Nxe5 *

[JuLieN]

First of all, I do not understand the post.
Did you mean to say Bxa6 loses a tempo?

A tempo is an expression, in italian language, meaning that someones plays instantly, without even taking time to think.

[kgburcham]

First of all, I do not understand the post.
Did you mean to say Bxa6 loses a tempo?

A tempo is an expression, in italian language, meaning that someones plays instantly, without even taking time to think.

"when a player takes one more move than necessary, the player loses a tempo"

Thanks Julien, I thought he meant as my definition explains. I thought he meant "a wasted move" thus losing a tempo.
best to you,
kgburcham

[JuLieN]

First of all, I do not understand the post.
Did you mean to say Bxa6 loses a tempo?

A tempo is an expression, in italian language, meaning that someones plays instantly, without even taking time to think.

"when a player takes one more move than necessary, the player loses a tempo"

Thanks Julien, I thought he meant as my definition explains. I thought he meant "a wasted move" thus losing a tempo.
best to you,
kgburcham

No problem. Chess is a real international game, with lingo coming from all languages ! From german with blitz, zeitnot, zugzwang ; french with en Passant, a tempo from Italian, and even the name itself, as you know, comes from persian shatranj.

[Bloodbane]

I don't think it's strange at all to play Bxa6 very quickly, you only have to see that if Ra8 then Qb5.

EDIT: Also I'm pretty sure that every engine is going to go Bxa6.

[OneTrickPony]

Well, only natural moves in this game and maybe he is getting tired/have problems visualizing endgames. I wouldn't consider this game the slightest reason to begin thinking of cheating possibility.

18.Bxa6 was played a tempo, which is not very natural.

18.Bxa6 is the only reasonable move once you took on c5. Anything else would be very suspicious.