The US top chess Grandmaster Hikaru Nakamura may be in the middle of the largest calendar clash so far this year. Nakamura has just been announced as player in the 2013 Norway Chess which takes place 7-18 May. Five of the playing dates overlap with the US Chess Championship 2013, where he is the top invited player so far.
The US Championship organizers from the Saint Louis Chess Club announced the 5th anniversary event back in January, a little after the surprising invitation for Fabiano Caruana.
However, now after the official announcement of Norway Chess 2013, it seems one of the events will lose an important player in the lineups.