World chess number one Magnus Carlsen has quit a major tournament after being told he could not carry on playing while wearing jeans.
The chess great had been defending his titles at the FIDE World Rapid and Blitz Chess Championships in New York when officials made the request.
The grandmaster said he had offered to change his trousers for the next day, but was fined and told he needed to change immediately.
The chess federation (FIDE) said its dress code regulations were designed to “ensure fairness and professionalism for all participants”.
Carlsen is a high-profile figure in chess who has attracted some controversy in recent years.
Last year, he settled a long-running legal dispute after accusing a rival of cheating in a tournament.
On Friday he pulled out of the championships for the short form versions of the game due to the dress altercation. Carlsen had been both the reigning Blitz and Rapid Chess champions.
He added he wouldn’t be appealing the decision, saying: “Honestly, I am too old at this point to care too much.”
He said he had been wearing jeans for a lunch meeting, and “didn’t even think about” swapping them for a different pair of trousers when heading to the tournament.
He turned up wearing a shirt, blazer, dark jeans and dress shoes and played a few rounds before being asked to change.
When his offer to change for the next day was refused, Carlsen said it then “became a bit of a matter of principle for me.”
In a statement, FIDE confirmed the 34-year-old was fined $200 (£159), and said its rules were applied “impartially”. They cited a case where another player was fined on the same day before changing his shoes.
Carlsen is a five-time World Chess Champion, and retains the top ranking in the sport.
The Norwegian has long been considered a maverick in the chess world since becoming a grandmaster – the top title in chess – at the age of 13.
In a now-settled dispute with opponent Hans Niemann, Carlsen quit a tournament in 2022 after Niemann beat him, before going on to accuse his American rival of cheating.
Niemann had denied the allegations, and even said he would “strip fully naked” to prove his innocence.
The pair went on to settle a $100m (£79m) lawsuit in August last year.