The teenage grandmaster at the eye of the cheating storm that has engulfed chess is suing the world champion Magnus Carlsen and others for defaming him and conspiring to ruin his career.
Hans Niemann, 19, has filed a lawsuit, seeking at least $150 million (AUD) in damages.
The suit claims that Niemann's upset victory over Carlsen in September resulted in a wave of defamatory statements accusing the teen of cheating.
"With this lawsuit, Niemann will set the record straight," Niemann's lawyers, Terrence and Darren Oved, said in a statement to ABC Sport.
"This is not a game. Defendants have destroyed Niemann's life, simply because he had the talent, dedication and audacity to defeat the so-called 'King of Chess'."
In addition to Carlsen, the lawsuit lists his company, Play Magnus, and another online chess site, Chess.com, as defendants, as well as Chess.com boss Daniel Rensch and American grandmaster Hikaru Nakumura.
Chess.com is in the process of taking over Play Magnus in a $130 million merger between the two largest online chess groups.
Shortly after Carlsen lost to Niemann and withdrew from the Sinquefield Cup in protest, Chess.com revoked Niemann's invitation from its Global Championship and banned him from its events.
A few weeks later, it released a 72-page report highlighting more than 100 online games between 2015 and 2020 in which it believed Niemann had cheated.
Niemann had already admitted to cheating online when he was 12 and 16 years old, but said those had been isolated instances that he described as the biggest mistakes of his life.
"We are saddened by Hans Niemann's decision to take legal action against Chess.com," the company's lawyers, Nima Mohebbi and Jamie Wine, said in a statement to ABC Sport.
"Hans confessed publicly to cheating online in the wake of the Sinquefield Cup, and the resulting fallout is of his own making. As stated in its October 2022 report, Chess.com had historically dealt with Hans's prior cheating privately, and was forced to clarify its position only after he spoke out publicly.
"There is no merit to Hans's allegations, and Chess.com looks forward to setting the record straight on behalf of its team and all honest chess players."
The lawsuit claims that the cheating allegations have "destroyed Niemann's remarkable career in its prime and ruined his life".
It says he can no longer compete in the majority of FIDE-sanctioned tournaments, and that he can't find employment as a chess teacher at a reputable school.
"My lawsuit speaks for itself," Niemann tweeted on Friday morning (AEDT).
