[veidelis]

I don't understand why a GM would need to explain some of his moves precisely and with a deep understanding of the position as some commentators here point out. Why is that so indicative of cheating? It's known that classical chess has a lot of theory, and Hans himself admits that he checked an engine line the evening before the game. So what? Here's the quote:

" I didn’t guess it, but by some miracle I checked this today, and it’s such a ridiculous miracle that I don’t even remember why I checked it. I just remembered 12…h6 and everything after this, and I’ve no idea why I would check such a ridiculous thing, but I checked it, and I even knew that 13…Be6! is just very good. It’s so ridiculous that I checked it. " https://chess24.com/en/read/news/sinquefield-cup-3-niemann-b...

[ebiester]

It's subtle, but the sheer amount of time that it takes to become a top level GM make it such that there's a bit of "GM Speak" that all of them seem to do. So, there is first a cultural variation: the way he speaks doesn't sound like the rest of the experts. By itself, it isn't damning.

However, people at the GM level also tend to have an ability to look at a position and remember what they were thinking at that point of time. They internalize lines in a way that is a branch of moves. So, in this case Be6! is such a sharp position that you would expect them to talk a bit through it because it takes a lot of prep.

Further, when they turned off Stockfish analysis, his analysis goes down sharply.

Further, he was banned from chess.com twice because he was cheating with an engine.

Further, when he was talking about a set of analysis, he made something up on the spot involving a match between Carlsen and GM Wesley So, and Wesley So said that what he had said was impossible for multiple reasons on another chess streamer's twitch.

It's a lot of little things that don't add up. It's like if you were in an interview and asking a developer to explain some code on their Github about ML, and they sounded like they didn't understand the basic principles of the model they coded. It doesn't mean they didn't write the code, but it casts suspicion.

[runnerup]

It's just one signal among others. All other GM's who have beat Magnus in classical format tournaments have been able to explain themselves very clearly. This guy can't. He might be a more "intuitive" player, or he might be cheating.

There's no smoking gun to show laypeople like you and I but people familiar with the scene and its norms do find this to be a salient point of data against Hans.

[nsv]

What people are speculating is that Magnus' prep got leaked to Hans leading to him researching this line. Of course just speculation, no hard proof. I tend to be of the mindset of "innocent until proven guilty".