‘Chess speaks for itself,’ Hans Niemann said last month after unexpectedly defeating the world number one, Magnus Carlsen, in Miami. He beat him again in the Sinquefield Cup in St Louis on 4 September. The following day Carlsen pulled out of the tournament, announcing his withdrawal on Twitter ten minutes before play was scheduled to start. He wouldn’t give a reason, but embedded a YouTube clip of Jose Mourinho saying: ‘If I speak, I am in big trouble.’