Simple cheating suspicion evidence detection for dummies

Simple cheating suspicion evidence detection for dummies

Postby CharlesRoberson » Wed Feb 21, 2018 2:10 am

Of course I don't literally mean dummies.

Due to my computer chess expertise, I've been asked to detect cheats on several occasions. Doing it properly is a complicated process, but a quick test to decide if you should involve an expert is simple and you only need a account - paid or free. Here is how:

1) login to
2) Slide down to Learn then click Analysis
3) a board will appear with options to the right
4) click on Load PGN
cut and paste the moves into the box or type them in
5) click the button that looks like a computer and magnifying glass
6) Now, click the tab that says quick

I did this for the following game
1. e4 c6 2. d4 d5 3. e5 Bf5 4. h4 h6 5. g4 Bh7 6. e6 fxe6 7. Bd3 c5
8. Bxh7 Rxh7 9. Qd3 Nf6 10. Nf3 Nc6 11. Qg6+ Kd7 12. Ne5+ Kc8 13. c3 cxd4
14. cxd4 Qc7 15. Bf4 Nxd4 16. Na3 Nf3+ 17. Nxf3 Qxf4 18. Ke2 Kd7 19. Rac1 a6
20. Rhd1 Qxg4 21. Qc2 Ke8 22. Rd4 Qf5 23. Qc7 e5 24. Nxe5 g5 25. Nac4 e6
26. Nd6+ Bxd6 27. Qxd6 Rd8 28. Nc4 Ne4 29. Qb6 Rf7 30. Rxe4 Qxe4+ 31. Ne3 d4
32. Rd1 Qf3+

7) you want to look at the statistical analysis- scroll back up to top of analysis (example from above game)

Code: Select all
Strength   White   Black
Excellent   20       27
Good        5        2
Inaccuracy (?!)   6   0
Mistake (?)   1   1
Blunder (??)   0   0
Forced     0      2
Best Move     42.9%   85.2%
Avg. Diff     0.80    0.08

So, here we see white had 6 inaccuracies, 1 mistake, 0 blunders and a best move percentage of 42.9%.
I would say insufficient info to suspect cheating for white.
On the other hand, Black has 27 excellent moves, 2 good moves, 0 inaccuracies, 1 Mistake, 0 blunders and a best move percentage of 85.2%.
After looking at the mistake, it is the kind of move that could have been easily confused with a computer suggested move. I'd say this shows sufficient evidence for suspicion. More analysis from an expert and possibly more data is needed to confirm the suspicion.

I post this because bringing such things to a TD is a timely manner is very important. If you wait until after the tournament to complain, it is too late.
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Joined: Wed Mar 21, 2012 2:38 pm
First Name: Charles
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Re: Simple cheating suspicion evidence detection for dummies

Postby sspencer » Mon Mar 12, 2018 4:24 pm

Ok so this peaked my interest and I played a game against a know and popular computer program. I am playing white, program is black, game set to 24 hours a move. Such as one can play on many online sites such as

1.d4 Nf6 2.f4 d5 3.e3 c5 4.Nf3 Nc6 5.Nc3 cxd4 6.Nxd4 Bg4 7.Be2 Bxe2 8.Qxe2 e6 9.Bd2 Bc5 10.Nf3 O-O 11.O-O-O Qe7 12.Ng5 h6 13.h4 b5 14.g4 b4 15.Na4 Bd6 16.Qg2 Nd7 17.Nf3 Nb6 18.b3 Nxa4 19.bxa4 a5 20.Kb1 Rfc8 21.h5 f6 22.g5 fxg5 23.fxg5 hxg5 24.Nxg5 Ne5 25.Rdf1 Rf8 26.h6 Nc4 27.Bc1 Be5 28.Rfg1 g6 29.Nf3 Qh7 30.Nh4 Rf6 31.Nxg6 Rxg6 32.Qxg6+ Qxg6 33.Rxg6+ Kf7 34.Rg5 Bf6 35.Rf1 Ke7 36.Rg6 Be5 37.e4 dxe4 38.h7 Rh8 39.Bg5+ Kd6 40.Rd1+ Kc7 41.Rh1 e3 42.Rg8 e2 43.Rxh8 Bxh8 44.Re1 Nd6 45.Rxe2 Kd7 46.Rd2 e5 47.Rd5 Ke6 48.Rxa5 1-0

Strength White Black
Excellent 40 43
Good 8 4
Inaccuracy (?!) 0 0
Mistake (?) 0 0
Blunder (??) 0 0
Forced 0 0
Best Move 74.5% 78.3%
Avg. Diff 0.08 0.06

To the best of my knowledge set this program up to play its best and did not handicap it. Neither I nor it made any Inaccuracy, Mistake or Blunders according to the analysis, yet the score at the end of that game was plus 7 for white. I actually made more good moves than it did. Knowing I was playing a program utilized an anti-program strategy.

Yet at the bottom shows me almost matching it move for move on best move percentage. I read and scoffed at the article in Chess life last month about cheating on This analysis proves I was right in doing so ha ha. So you are saying someone can look at these numbers and determine cheating by it? With all do respect I find that comically absurd.
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