NEW YORK – Hans Niemann, the teenage American grandmaster at the centre of an alleged cheating scandal, sued world champion Magnus Carlsen, online platform Chess.com and others for slander and libel on Thursday and is seeking at least US$100 million (S$143 million) in damages.

The lawsuit, filed at a US District Court in Missouri, also lists Carlsen’s online chess platform Play Magnus, Chess.com executive Danny Rensch and American grandmaster Hikaru Nakamura as defendants.

In his complaint, Niemann, 19, said the 31-year-old Carlsen, the five-time reigning world champion, Mr Rensch and Nakamura have inflicted “devastating damages” on his reputation and career by “egregiously defaming him”.

It accuses them of “unlawfully colluding to blacklist him from the profession to which he has dedicated his life”.

“Since the age of 16, Niemann’s sole means of supporting himself has been from the money he makes teaching chess and participating in chess tournaments,” the lawsuit said.

The Wall Street Journal reported that the complaint also said that because of the cheating allegations, a tournament that Niemann was intending to play in stopped all communications with him. It added that another grandmaster cancelled a match with him and he was also unable to obtain employment as a chess teacher at a “reputable school”.

After Niemann “soundly defeated” Carlsen at the Sinquefield Cup tournament in Missouri on Sept 4, the Norwegian “viciously and maliciously retaliated against Niemann by falsely accusing Niemann, without any evidence, of somehow cheating during their in-person game”, the lawsuit said.

Chess.com, the lawsuit said, “banned Niemann from its website and all of its future events, to lend credence to Carlsen’s unsubstantiated and defamatory accusations of cheating”.

Carlsen’s surprise defeat by Niemann and his subsequent withdrawal from the Sinquefield Cup in St Louis, Missouri, in September sparked a furore of comments and allegations, including from Nakamura, that the American had cheated.

Weeks after the Sinquefield Cup, the Norwegian resigned after just one move against Niemann in an online tournament and said later in September that he believed the American had “cheated more – and more recently – than he has publicly admitted”.

In a statement on Thursday, lawyers for Chess.com said there was no merit to Niemann’s allegations and that the company was saddened by his decision to take legal action.

“Hans confessed publicly to cheating online in the wake of the Sinquefield Cup, and the resulting fallout is of his own making,” the statement read.

“Chess.com looks forward to setting the record straight on behalf of its team and all honest chess players.”

Representatives for Carlsen and Nakamura did not immediately respond to a request for comment.

‘Ready to play naked’

Chess.com banned Niemann on Sept 5, shortly after the first accusations were made. It published a report earlier in October that said he had likely cheated more than 100 times in online games.

Niemann’s lawsuit suggested that the move by Chess.com was made under pressure from Carlsen, whose Play Magnus company is currently being acquired for US$83 million by Chess.com.

“Carlsen, having solidified his position as the ‘King of Chess’, believes that when it comes to chess, he can do whatever he wants and get away with it,” the complaint said.

His lawsuit said that Chess.com “banned Niemann from its website and all of its future events, to lend credence to Carlsen’s unsubstantiated and defamatory accusations of cheating”.

Niemann had previously been banned from Chess.com, having admitted to cheating when he was between 12 and 16 years old, but denies the most recent accusations. He has denied any wrongdoing while contesting over-the-board games and has claimed to be “ready to play naked”, if necessary, following gossip that he had used anal beads to receive aid.

The lawsuit further accused the Florida-based Nakamura, an influential streaming partner of Chess.com, of publishing “hours of video content amplifying and attempting to bolster Carlsen’s false cheating allegations”.

The International Chess Federation announced on Sept 29 that it was opening an investigation into the accusations of cheating. REUTERS, AFP