The chess world has been rocked with a potential cheating scandal with the world champion Magnus Carlsen, playing white, withdrawing two weeks ago from a tournament after losing against Hans Niemann, and then posting a cryptic tweet that observers interpreted as suggesting that Nieman had somehow cheated.. Then two days ago in a different tournament, this time played online, Carlsen, playing Niemann again, resigned after just one move, delivering another shock to the chess world.

On the surface, one would think that chess would be one of the hardest games at which to cheat. And that was undoubtedly true back in the day when there was no internet or cell phones and chess algorithms on computers were not that good. But nowadays powerful chess engines can quickly arrive at the best move in any situation, so much so that they are better than the best human players. when spectators follow chess matches, they get immediate information on the quality of a player’s moves against that of the chess engine.

The trick then is to convey that chess engine move move to the player. While various precautions are taken to prevent such communication, they are not foolproof.

While there is no evidence that Niemann had in fact cheated in that game with Carlsen, the 19-year old’s history does not inspire confidence in his integrity.

The Guardian spoke to two sources in the chess world, who both said that if top players knew that a move that gave them a significant advantage existed – perhaps with the use of some sort of signal – it would help them to find it more often than not.

After his victory against Carlsen, Niemann claimed that “by some ridiculous miracle” he had guessed what his opponent’s unusual opening would be and prepared deeply for it. “It must be embarrassing for the world champion to lose to me,” he said. “I feel bad for him.”

The next day, Niemann did admit he had cheated in the past in online events with the help of computer assistance when he was a 12- and 16-year-old – but insisted he was now “clean” and was even prepared to play naked to prove his innocence. However the website Chess.com has since said they believed Niemann had cheated online more frequently, and had shown him the evidence. Niemann has been banned from the site and Chess.com events.

Niemann has his defenders.

The world’s leading expert on cheating in chess, Dr Kenneth Regan, has analysed all of Niemann’s games over the past two years and his conclusion is there is no reason whatsoever to suspect him of cheating. However Carlsen, the most powerful player in chess, is clearly unconvinced.

The article goes on to discuss how cheating has been done in the past

It is far easier to do so over the internet, where some players have been caught using computer engines to help them to find good moves. However it is tricker over the board where players are often scanned beforehand for electric devices.

That doesn’t mean it is not possible, however. Perhaps the most high-profile case involved the French players Sébastien Feller, Arnaud Hauchard and Cyril Marzolo, who were found guilty of cheating at the Chess Olympiad in 2010. The elaborate scheme involved Marzolo analysing the games of Feller on the internet, before sending suggestions to Hauchard by SMS. He then relayed them to Feller by standing behind one of the other players’ tables in a predefined coded system, where each table represented a move to play. In 2019 Feller was given a six-month suspended prison sentence for his behaviour.

More recently, the Latvian grandmaster Igors Rausis was banned for six years after being caught looking up moves on a phone he had hidden in the toilet.

Niemann gave a long interview where he passionately defended himself from the charge of cheating.