Carlsen v Niemann: the cheating row that is rocking chess – explained

Allegations of cheating – including wild speculation involving vibrating anal beads – which have rocked chess to its core. A fortnight ago the world champion Magnus Carlsen pulled out of a tournament for the first time in his career – and then, on Monday, he stunned the sport again by resigning a game after just one move. Both times Carlsen was faced with the same opponent, the 19-year-old American Hans Niemann.

After Carlsen pulled out of the $500,000 (£433,000) Sinquefield Cup after a shock defeat against Niemann with white pieces. The day after the loss, the world champion posted a cryptic tweet that included a video clip of José Mourinho saying: “If I speak, I am in big trouble.” There was soon frenzied speculation over Carlsen’s motives, with the American grandmaster and popular streamer Hikaru Nakamura claiming the world champion had withdrawn because he thought Niemann was “probably cheating”.

Organisers of the Sinquefield Cup announced additional anti‑cheating precautions, including a 15-minute delay in the broadcast of the moves and increased radio-frequency identification checks. Niemann, who had won two of his first three games at the event, proceeded to lose or draw his final six. However, no evidence of cheating was found.

One theory doing the rounds on the internet, popularised by Elon Musk, is that Niemann used vibrating anal beads to help him. Another suggestion was that the American may have somehow been leaked Carlsen’s opening preparation. Both are denied by Niemann. But others have suggested the American, who says he spends 10-12 hours a day on chess, may have simply been the better player on the day.

The Guardian spoke to two sources in the chess world, who both said that if top players knew that a