There has been speculation that anomalous values of a correlation metric1 may hint to the use of outside assistance.
Examination of Hans Niemann vs Matthieu Cornette surprises:
this looked like a perfect game
one-hundred percent - wow!
- 90% Sébastien Feller (Paris 2010 - known to be cheating)
- 72-75% Correspondence World Champion (pre engine era)
- 72% Bobby Fischer during 20 consecutive winning streak
- 70% Carlsen at his best
- 69% Kasparov at his best
- 62-67% Super GMs
- 57-62% GMs
How often do super Grand Masters score 100% in this correlation metric. For example, 1/1,000, 1/1,000,000 1/1,000,000,000 etc.
- Nakamura mentions:
Fischer had 0 games at 100% in his entire career
Some methods for calculating the correlation statistic can be made to exclude book openings (and even more impressively book openings at the time of the game).
It may be sensible to exclude short games (e.g. Junior Speed Chess Champion, Arjun Erigaisi, is said to have 1 game at 100%, however, it was a 10-move game; the shortness of this game is notable).
In the days following the release of Yosha's video, there has been some confusion around the methods used to attain the alleged 100% engine correlation. Grand Master Ben Finegold dismisses the idea of them entirely:
A lot of the information on the internet which says Hans played 100% in all these games, that's all nonsense. ... None of that is true.
1 Let's Check