Ms. Paikidze-Barnes, 22, also organized a petition calling for the competition’s governing body, the Fédération Internationale des Échecs, or World Chess Federation, to either move the competition from Iran or persuade Iranian officials to make wearing a hijab an option instead of a requirement.

According to a statement from the federation’s spokeswoman, Anastasiya Karlovich, posted to Chess Daily News, the organization has defended its decision to host the championship in Iran. For one, the statement said, no other country had asked. For another, Iran held a global event in February that went off well.

“There were no complaints from the players or officials, and everybody respected the laws of the country, including the dress requirements,” Ms. Karlovich wrote.

Both Ms. Paikidze-Barnes and FIDE did not immediately return an email request for further comment on Friday.

At least one other player has vocally criticized Ms. Paikidze-Barnes’s decision to boycott. Ms. Paikidze-Barnes’s comments have also alienated Iranian women, including Mitra Hejazipour, an Iranian chess player and fellow grandmaster.