Seconded re: Neimann's analysis. Specifically, he stated in a post-game interview that Carlsen had played the same Nimzo-Indian g3 line in a prior tournament, even though that never happened.

For the sake of the sport, I hope Neimann didn't cheat, but I doubt we'll ever know for sure.

https://www.chessgames.com/perl/chessgame?gid=1981206 (a blitz to be compared against https://www.chessgames.com/perl/chessgame?gid=2372960 from 2 days ago).

Yeah, but Move 6 is different and it changes the whole dynamics of the game.

Prior to Move 6 this is a well known line with 700 hundred high level games, and Magnus (apparently) never played the line with 6.a3 before, so I find Hans's claim extremely dubious.

Still not an evidence that he cheated, but I agree that sum of signals e.g. prior cheating ban on chess.com, incoherent after game analysis without engine help and in general never being worse against 4 Super GMS and having a winning position against all of them does not paint a good picture. Something smells, but we will probably never know.

Edit: corrected move#

Good catch. I was searching for a game without Nf3, but this is effectively a transposition.

One minor point folks aren't mentioning that I think works in Neimann's favor - Carlsen is known for enjoying the Catalan, and the opening in the game was essentially a Nimzo/Catalan hybrid. This fact makes Neimann's supposed pre-game prep a bit more palatable. Everything else (postgame interview, past history, Twitter antics) seems to work against Neimann though.

My question is - if Neimann did cheat, how? Doesn't seem like something that can be done easily in an OTB tournament.

You could stick the computer in your shoe, like the submission suggests?

Or you could swallow a buzzer? The input could come from someone who watches the board from afar?

They metal detected & RF frequency detect before the round 4 match.

RF detection before a match seems useless, unless the device is in constant communication.

I don't know enough about those devices and metal detectors to be able to tell whether that's effective mitigation. Could one make a device small enough to be hard to detect?

There are rumors that Carlsen's prep got leaked and that Niemann knew what was going to played the morning of.

Although this is pure speculation, it seems to be a more plausible and satisfactory explanation if Niemann did in fact cheat. It would also explain why Carlsen would withdraw from the tournament rather than continuing.

Did Magnus ever played 6.a3 line before in this well known Nimzo variant? The Game with So doesn't have it.

Are you accusing him of cheating today despite the 15 minute delay and heightened security?

The 15 minute delay was introduced after the Magnus game.

We are talking about the Firouzja game.

No, the accusation is that the sum of signals doesn't look good.

It's binary. Either he did cheat today or he did not. If he did not then who cares what his post analysis looks like after drawing the #4 player in the world and being +3 at some point. The only reasonable analysis is to declare him a cheater today or discard the interview. To say that the interview would point to him cheating vs Magnus but not today is nonsense.

You can always say 40% cheater, 60% non cheater in this one game, but this updates the priors for future game considerations. At some point the priors will be such that the belief in the risk of cheating (which needs not be more than 50%) will cause the player to not be invited.

I don’t think this is right. The idea seems to be that his post-game interview shows he didn’t understand the positions very well despite playing them accurately, so he may have cheated. But a) today there was a huge amount of extra security and specific scrutiny on him, b) he drew despite having a substantial advantage at one point, and c) a bad interview where he fumbled some stuff would be a nothing-burger if it hadn’t come after an accusation. It seems much more likely that this is a swirl of confirmation bias, not sound adjustments to priors. No one seemed to think his play was suspicious before the Magnus tweet and now everyone is reading tea leaves.

I got "busted" in school for "cheating" in an assembly language lab. I fumbled explaining the code to the TA, and he thought I had copied code from someone else. Explaining and performing are two different skills, it's very possible to be able to do things that you can't describe.

I agree that he probably did not cheat vs firouzja. Even vs Carlson my money is at most the line magnus wanted to play somehow got leaked. It’s hard to imagine getting live engine support otb at a modern tournament.

Right. But the specific point in this thread is that his horrible analysis after the Firouzja game was suspicious, which doesn’t lend any weight to the accusation unless we’re also claiming he cheated in that one.

Why is it hard to imagine? It's easy to imagine him getting signals from the audience for example which can be done in multiple ways. I am not up to date with the state of metal/RFID detectors but simplistic ones they use at chess tournaments are probably possible to game as well.

It’s easy to imagine almost anything. The question isn’t whether he could but rather whether he did. I’m challenging the reasons many people believe he did, or likely did.

The point is that people keep bringing his post game interview today which is only relevant if he cheated in today's game, when security and scrutiny were at their highest.

So called Bayesian analysis frequently goes awry because of its ultimate dependence on assumptions (priors). But you don't even bother to do a calculation.

The event might be binary but our knowledge isn't. You may think he is likely cheating but you're not sure. You won't declare him a cheater but you will be suspicious.

What is the reasoning of people accusing a player of the OTB cheating? That he somehow (with the help of a computer?) got up to +3 at some point against said #4 player, but then decided to stop cheating?

If he is that 'bad' to draw a +3 position, how did he achieve this position in the first place?

Seems ironic to ask this on a post where a guy's cheating device malfunctions causing him to lose. There could be limitations which prevent him from cheating completely accurately

No, not ironic at all. Said device was extremely unreliable and failed to win even 2 games - while the person you accuse of cheating has improved from 2400 to 2700 in about 2 years. Pretty reliable cheating device he had, only to fail at the crucial moment.

Also, consider this: Nakamura knows that the position is good, but does he know it before he sees the evaluation, or after? Because it is a fact that when top player knows it is +3, he can explain why it is so good. But just looking at the board, without knowing the evaluation, he might have a very different conclusion.

I don't know about his game yesterday with Firouzja, but the rumor is that Magnus thinks Niemann got hold of his opening preparation before the game, which would put him at a huge advantage.

This is not the point. The point was that he good enough to nearly beat the #4 in the world if he wasn't cheating.

Everyone has their good days and bad days. Elo rating estimates a probability of an outcome, and even with 2880/2680 it is far from zero.

this guy is right