Carrying a grudge: Chess champ quits after one move against U.S. rival amid cheating controversy

The cheating controversy roiling the world of elite chess shows no signs of cooling down as Norwegian world champion Magnus Carlsen played one move and then quit in apparent protest in his game against young American rival Hans Moke Niemann Monday.

The abrupt resignation in a strong online tournament came just weeks after Mr. Carlsen, who has dominated the game as champion for more than a decade, withdrew from the Ninth Sinquefield Cup tournament in St. Louis a round after losing to the much lower-rated Mr. Niemann, heavily insinuating that Mr. Niemann somehow received help — human or computer-based — during their game.

Sinquefield tournament officials said they could find no evidence of foul play — which Mr. Niemann heatedly denied — but also announced there would be a 15-minute delay before moves were posted to the internet for the remainder of the tournament, a sign that there were doubts about the honesty of the play.

A highly anticipated re-match between the two elite grandmasters was set for Monday’s second day on online play in the Julius Baer Generation Cup. Both players could be seen on the video link during the live broadcast on Chess24.com as play began.

But Mr. Carlsen, playing the Black pieces, moved his knight for the first move and then shut down his video feed and logged off after Mr. Niemann made his second move, effectively resigning the game.

Chess24 commentator and chess grandmaster Tania Sachdev appeared stunned by the champion’s “unprecedented” gambit, which she said suggested the controversy was far from resolved in Mr. Carlsen’s mind.

“Magnus [is] just refusing to play against Hans,” she said on the videocast Monday. “He will play the tournament, but he is saying ‘I will not play the game against him’. That’s making a very big statement.”