In the past month, 19-year-old Hans Niemann has emerged as the most-talked-about American chess player since Bobby Fischer. Found several years ago to be cheating in multiple online games by Chess.com, the world’s largest online chess site, Niemann in early September beat world champion Magnus Carlsen in an over-the-board tournament game. Carlsen withdrew from the tournament, implicitly accused Niemann of cheating, and refused to play him in a subsequent event.