The Sinquefield Cup is an annual chess tournament held in St. Louis, Missouri. It features some of the world's top players competing in a classical format, typically over several days. The event is named after Rex Sinquefield, a prominent chess patron and co-founder of the Saint Louis Chess Club. First held in 2013, the Sinquefield Cup has become part of the Grand Slam of Chess, attracting international attention. The tournament is known for its high level of competition and has seen many elite players, including Magnus Carlsen and Fabiano Caruana, participate.