It’s rare for an event to ignite not just the chess world but the world outside. Two previous events stand out, in positive ways: the Fischer–Spassky world championship match at Reykjavik in 1972, and more recently the Netflix drama The Queen’s Gambit which has inspired a generation of young female players. Now we have something decidedly negative which has the potential to turn people off the game completely.

It is beyond doubt that Niemann has cheated at online chess. Either two times or a hundred times, depending on who you believe. But there is no evidence that he has cheated at over the board chess. Of course there are suspicions: how did he gain 100 FIDE rating points so quickly, and how did he inflict a rare defeat on the strongest player in the world? Carlsen, and many others, clearly believe he must be up to something. Actual proof of underhand methods is another matter.

Niemann is clearly discredited online, but what does the OTB future hold for him? On one view, he has not been shown to cheat in this mode, and he will surely be scrutinised more closely than any other player in future. As if even his bowel movements will be watched. He, of all players, has no opportunity for wrongdoing. And it is an important principle in judicial and quasi-judicial matters that everyone is innocent until proven guilty.

But this is to assume that the worlds of online chess and OTB chess can be clearly separated. Yes, they have different procedures, and ratings in one form do not cross over to the other. But it is the same game involving the same mental and psychological processes. Knowing that your opponent has cheated online is bound to affect your play against the same opponent over the board. There is always the possibility that your opponent may have found some ingenious and hitherto undetected method of gaining an unfair advantage. Once the taint arrives, it’s very hard to make it go away.

It would not be surprising if more chess players followed Carlsen’s lead and theatrically resigned against Niemann in the early stages of the game – or even refused to play him altogether. When these things reach a critical mass, what can the chess authorities do? One option would be to ban Niemann from OTB chess. But that is hard to reconcile with notions of fair play.

Maybe the solution lies with Niemann himself. While maintaining his innocence in the OTB format, he could acknowledge the furore that his online actions have caused and the psychological problem he has inflicted on his opponents. He could voluntarily withdraw from all forms of chess and self-isolate for a significant time, at least a year. And then come back to the OTB world and start again. He would be a weaker player through lack of practice, but the chess world might have calmed down by then and might be ready to accept him on equal terms.