It’s over. Magnus Carlsen’s undefeated streak in classical chess has finally come to an end, after 125 games. It is hard to exaggerate what an unlikely accomplishment this is: Carlsen faced top-flight opposition in almost every game, winning 42 and drawing 83. He was beaten by the Polish grandmaster Jan-Krzysztof Duda at the Altibox Norway Chess tournament (played over the board!) earlier this month.