A timeline of chess' massive cheating controversy

• Sept. 5: Carlsen, 31, withdrew from the tournament, sending a cryptic tweet that implied Niemann had cheated. The event beefed up its anti-cheating measures in response and Niemann passed the screens — but didn't win another match.
• Sept. 6: Niemann admitted that he'd cheated twice online as a young kid, but denied ever cheating in over-the-board (in-person) chess.
• Sept. 8: Days after Chess.com privately de-platformed Niemann, the website publicly explained that Niemann had a longer history of cheating than he let on.
• Sept. 19: Niemann and Carlsen met in a rematch on Monday, this time in an online tournament called the Generation Cup. After one move, Carlsen turned off his webcam and resigned in protest.

Between the lines: Over the past two decades, technology has made cheating in chess rather simple. All one needs is widely available AI software ("chess engines") that follows a match in real-time, determines the best moves, and routinely beats the world's best players.

• During in-person tournaments, the challenge is relaying those moves to the player. That requires an accomplice to run the engine and send signals when there's a particularly impactful move to make.
• One popular theory is that Niemann received signals through vibrations in his shoes. Another, far grosser explanation is that he used vibrating anal beads.

Yes, but: Not everybody thinks Niemann cheated. In fact, the leading expert on chess cheating detection analyzed all of his games over the last two years, including online games, and concluded that he's clean.

The big picture: We may never know if Niemann cheated in St. Louis. But the fact that he could have done so without being detected raises significant questions about the future of chess.

• Like post-steroid era baseball, chess could soon face a reality where any run of success is met with skepticism and cheating accusations.
• Tournaments may need to have more thorough screenings or alter how matches are broadcast (think: longer tape delays) to put competitors and fans at ease.
• Russian grandmaster Ian Nepomniachtchi suggested "playing naked in a locked room" is the only way to eliminate cheating completely.
• He was joking, but "the mere idea suggested how extraordinary the rules might have to become to eliminate even a whiff of funny business," writes WSJ's Joshua Robinson (subscription).

What's next: Carlsen and Niemann could meet again this weekend in the finals of the Generation Cup if they win their quarterfinal matches Thursday and semifinal matches Friday — and assuming Carlsen shows up.