Photograph: US National Championship

The US championship has been overshadowed by an assault charge levied at 17 year old Christopher Yoo after he lost to Fabiano Caruana in a winning position. After losing to the defending US Champion, Yoo is alleged to have struck a videographer in the back. St Louis police later apprehended and arrested the young grandmaster.

Yoo was expelled from the tournament, and according to FIDE regulation his results will be annulled as he hadn’t played at least half of the matches. He has subsequently been banned from the US National Championships and the St Louis chess club. Naturally, his reaction has also evoked outrage from the wider chess world, with GM Levon Aronian, who saw a video of the incident, describing it as “awful”. Yoo has since published this apology;

"I am really sorry for hitting the videographer. I was disappointed losing the game to Caruana and lost my temper. That’s no excuse, I know," he said. "It was a serious mistake. Every day I wish I could go back in time and undo it, but I can’t."