Hans Niemann announced on Thursday that he was taking legal action against Magnus Carlsen and a number of companies and individuals.

"My lawsuit speaks for itself," he wrote on Twitter, playing on a past interview of his where he had boasted that "the chess speaks for itself" after a strong victory.

Niemann's lawsuit accuses the defendants of "egregiously defaming him and unlawfully colluding to blacklist him from the profession to which he dedicated his life."

"Niemann seeks damages in an amount to be determined at trial, but no less than $100,000,000," the court filing said.

The 19-year-old American player has been at the center of allegations of cheating initially leveled by Carlsen, who withdrew from the 2022 Sinquefield Cup tournament after losing to Niemann in September. Soon after, playing Niemann in a different online competition, Carlsen resigned after playing just one move.

Niemann issued the lawsuit shortly after the conclusion of the US Chess Championship, in which he finished in 9th after a slow start and a three-game winning streak to wrap up the competition.

Who is Niemann suing, and on what grounds?

Niemann accuses Carlsen of seeking to use his "unparalleled stature and influence in the chess community" to try to sideline him from the game, portraying Carlsen as upset at having lost to him.

"Following Carlsen's baseless and retaliatory accusations, Carlsen unleashed his media empire to fan the flames of Carlsen's cheating allegations, drown out the legitimate evidence refuting them, blacklist Niemann from top-level chess tournaments, and protect, at any cost, his eponymous Play Magnus brand and status as 'King of Chess,'" the court filing reads.

Besides Carlsen, Niemann is also suing the Play Magnus Group — Carlsen's chess product company — the chess website chess.com, which recently moved to buy out the Play Magnus Group, senior chess.com official Daniel Rensch, and American grandmaster and popular streamer Hikaru Nakamura.

Chess.com followed up on Carlsen's allegations against Niemann by releasing data on his past play that it said gave it reason to strongly suspect cheating in various online games, and to a greater extent than the few instances Niemann had admitted to early in the scandal.

The company released information including Niemann's private messages with Rensch acknowledging cheating in some instances and negotiating his return to the site after an anonymous suspension.

Chess.com also said Niemann was one of dozens of "titled" players — such as grandmasters, international masters and other ranks — known to have cheated online.

Niemann, meanwhile, includes Nakamura in the lawsuit, describing him as "chess.com's most influential streaming partner," and saying that in the aftermath of Carlsen's allegations, Nakamura colluded to publish "hours of video content amplifying and attempting to bolster Carlsen's false cheating allegations."

Niemann's lawsuit accuses the defendants of slander, libel, unlawful group boycott — he has since been excluded from several matches and competitions — tortious interference with contract and business expectancies, and civil conspiracy.

Has Carlsen or chess.com provided any real evidence?

The answer to this is debatable, although Niemann's lawsuit argues not.

Cheating allegations are as old as the game, but it has become easier and more tempting than ever before in the information era, with programs vastly superior to any human players available to anyone with a smartphone.

There's no hard evidence of Niemann cheating in his in-person, "over the board" win against Carlsen in St. Louis at the Sinquefield Cup, where security checks were in place.

Analyses of that game suggest the five-time world champion was not at his best, and Niemann's lawsuit says "top chess analysts ... concluded that Niemann's victory resulted more from Carlsen's particularly poor play than Niemann's particularly exceptional play."

Carlsen, for his part, said last month that Niemann's behavior in that September 4 game raised his suspicions further: "I had the impression that he wasn't tense or even fully concentrating on the game in critical positions, while outplaying me as black in a way I think only a handful of players can do."

But chess.com's computer analysis of Niemann's past play did point to a high likelihood of Niemann cheating in online competitions, some as recent as 2020. It also included confessions from Niemann communicated to Rensch, albeit at the time on the understanding that these would be kept private.

Other players close to Niemann have since come forward and said that admitting to wrongdoing, in what used to be a private process, was the easiest way to get their accounts reactivated on the biggest online playing platform — implying it was easier to admit and apologize to chess.com than to fight to reinstate their reputations.

Niemann's lawsuit also describes chess.com's takeover of the Play Magnus Group as a bid to "monopolize the chess world."