Magnus Carlsen completed a remarkable few days at the World Rapid and Blitz Championships on Wall Street, New York, when the Norwegian, 34, who first withdrew then returned to the event after Fide rescinded its ban on jeans, controversially agreed to share the Blitz crown with his old rival, Russia’s Ian Nepomniachtchi, while their final sudden-death tie-break was still in progress.

The pair were survivors from an eight-player knockout, and Carlsen took a 2-0 lead before Nepomniachtchi fought back to 2-2. Official Fide rules then called for an indefinite series of sudden-death games, the chess equivalent of a penalty shootout, but after only three of these, all featuring conservative strategy by both sides, Carlsen suggested that they share the title at 3.5-3.5.

Nepomniachtchi, who had never won a world championship despite appearing in two classical finals, agreed. As with the jeans issue, the matter was referred to Fide’s Russian president, Arkady Dvorkovich, who was not in New York.

Dvorkovich probably felt he had little choice but to rubber stamp the agreement by the players. He would have been pilloried in Moscow as preventing a Russian world champion had he ruled otherwise, and a negative could also have provoked a series of the notorious Berlin draws, the standard method for a quick mutually agreed half point. However, that course of action would have brought the players into disrepute, and it is more likely that an inspired game or a blunder would have settled the final.

The audience on Wall Street applauded the decision, but the considerable online reaction from professional players and fans has been mostly critical. It was the first ever shared over-the-board individual world title in chess history, equivalent to the shared high jump gold medal at the 2021 Tokyo Olympic Games, but with no parallels in the great majority of sports. Carlsen was laid back about it.

What occurred on Wall Street on Tuesday is a huge contrast with Anatoly Karpov v Garry Kasparov in 1984-85, a first to six wins world title match lasting five months over the Moscow winter where Karpov led 5-0 for a long while but could not overcome Kasparov’s rearguard action. The match was halted at 5-3 due to concerns over Karpov’s health, but replayed later in 1985. That match was one game a day classical chess, and not just three-minute blitz as with Carlsen v Nepomniachtchi.

Carlsen wrote on X: “I’ve never prearranged a draw in my career. In the video I’m joking with Ian in a situation with lacking decisive tie-break rules. This was obviously not an attempt to influence Fide. It was said in the spirit that I thought Fide would agree to our proposal. If anything it was a bad joke given the gravity of the situation. I think the match itself showed two players playing high-level chess, equally matched and both deserving of a win.”

Perception matters. Tuesday evening may prove to have been a significant and possibly decisive moment in the eternal argument over whether Carlsen or Kasparov is the greatest of all time.

The rules will surely need changing, although in the past Fide has refused to embrace the obvious Armageddon tie-breaker widely used in other events. In Armageddon, White has more time but a draw on the board counts as a win for Black on the score table. Long ago, in 1983, Fide determined the winner of a Candidates match by a roulette wheel.

Earlier, in the blitz quarter-finals, Carlsen defeated Hans Niemann in a rematch of their controversial game from the Sinquefield Cup which led to cheating allegations and a $100m lawsuit. Carlsen won 2.5-1.5 despite being checkmated in their second game.

The chief arbiter, England’s Alex Holowczak, followed mandatory rules with his decision to omit Carlsen from the round nine Rapid pairings and so triggering Jeansgate. Holowczak was subsequently singled out for criticism by Carlsen, along with the Fide chief executive, Emil Sutovsky, and the Fide vice-president, Vishy Anand.

Carlsen’s strictures could have been better directed at Fide’s athletes commission, whose chair, GM Ahmed Adly, authored the dress code with disproportionate penalties. In other Fide dress code documents, jeans are not excluded unless “torn or dirty”, and there is no mandatory punishment.

The sharp pace of a blitz tournament, where the time control is just three minutes for all your moves plus a two seconds per move increment, makes it a supreme test of instant decision making and of psychological equilibrium.

A video captured one of the negative moments, in which Vasyl Ivanchuk, now aged 55, played the well-known commentator Daniel Naroditsky, 29, in round 11, where the winner would have good chances to reach the quarter-finals. Ivanchuk spoiled it near the end, when 38 Re4! or 40 b8=Q! would have won, and was devastated.

Russia’s rising talent Volodar Murzin, 18, won Rapid gold with an unbeaten 10/13, a victory highlighted in the penultimate round by his spectacular black king march into the heart of the white defences. Earlier, Murzin defeated the world No 2 and US champion, Fabiano Caruana. The Open Rapid medals were a Russian clean sweep as Alexander Grischuk won silver and Nepomniachtchi bronze.

India’s Koneru Humpy won the Women’s World Rapid gold, repeating an earlier success from 2019. China’s Ju Wenjun, the reigning champion in classical chess, won the Women’s World Blitz, defeating her compatriot Lei Tingjie 3.5-2.5 in the final with a seventh game win after six draws. Ju was also the Rapid silver medallist, and is starting to dominate the women’s game in a style unmatched since the all-time top two, Judit Polgar and Hou Yifan.

3953: 1 Qh7+! Nxh7 2 Nf7+! Rxf7 3 Rxg6 mate.