SF. LOUIS – A 17-year-old chess grandmaster has been charged with assault after he punched a woman at a tournament at the Saint Louis Chess Club last week.

The Metropolitan Police of St. Louis told FOX 2 on Friday that Grandmaster Christopher Yoo, 17, was charged with fourth-degree assault and released to one of his parents as directed by juvenile courts.

According to the Saint Louis Chess Club, Yoo allegedly violated its code of conduct and safe play policies after losing a chess match. Yoo allegedly crumpled up a score sheet and stormed out of the tournament hall, hitting a videographer from behind after last Wednesday’s game.

In response, officials expelled Yoo for the remainder of the 2024 US Chess Championship in St. Louis, which ended Thursday, and also banned him from the Saint Louis Chess Club.

Event organizers say Yoo’s results from the first five rounds of the tournament will be declared invalid, and the tournament rankings have been adjusted accordingly.

“We take player behavior seriously and do not tolerate violations of our standards,” the Saint Louis Chess Club said in a statement last week. “We acted quickly to address this situation, ensuring a respectful and safe environment for everyone involved in the tournament.”

Yoo apologized for his actions in a statement posted to his parents Facebook and further distributed on the US Chess Federation website.

“First, Christopher wants to publicly apologize to the cameraman who was an innocent victim of his anger after losing a game of chess. Contrary to what some have suggested, the videographer did nothing to provoke Christopher. We hear he’s doing well, but we don’t have details and we pray he’s doing well both physically and emotionally. Her well-being is of deep concern to all of us,” the post said. “Christopher makes no excuses for his behaviour. He is just very sad and ashamed that he behaved in this way.”

According to Chess.comYoo is originally from California. He is considered one of the youngest American grandmasters with the highest title awarded in US professional chess. Yoo earned a spot in the US Championship in St. Louis winning the 2024 US Junior Chess Championship.