Chess Grandmaster expelled from US Championship following violent outburst after loss

ST. LOUIS — A chess Grandmaster was expelled from a tournament after an incident Wednesday at the U.S. Championship in St. Louis.

The Saint Louis Chess Club issued a statement saying Christopher Yoo was expelled from the tournament after violating the code of conduct. Video shows Yoo crumpling his score sheet after losing a match to Fabiano Caruana. The statement also says Yoo struck a videographer from behind.

The police were called to the incident. A spokesperson with the St. Louis Metropolitan Police Department confirmed that a 17-year-old was charged with fourth-degree assault. Police said he struck a 24-year-old woman in the back with his fist. He was released to a parent, and the matter would be handled in juvenile courts.

Video from the Saint Louis Chess Club shows the end of the round starting about 1:29.

The chess club said the tournament arbiter expelled Yoo from the competition. His results were annulled, and the standings would be adjusted. Players that were scheduled to face Yoo would get a bye.

The U.S. Championship determines the country's chess champion each year. The Saint Louis Chess Club has hosted the tournament since 2009.

Caruana is the reigning U.S. champion. He also won in 2022 and 2016.

Yoo was, at the time, the youngest international master in American chess history at 12 years old. Abhimanyu Mishra later took that record, becoming the youngest international master at 10 years old.

Yoo became a Grandmaster in 2022.