The U.S. Chess Championship is an invitational tournament held to determine the United States chess champion. Begun as a challenge match in 1845, the U.S. Championship has been decided by tournament play for most of its long history. Since 1936, it has been held under the auspices of the U.S. Chess Federation. Until 1999, the event consisted of a round-robin tournament of varying size. From 1999 to 2006, the Championship was sponsored and organized by the Seattle Chess Foundation (later renamed America's Foundation for Chess [AF4C]) as a large Swiss system tournament. AF4C withdrew its sponsorship in 2007. The 2007 and 2008 events were held (again under the Swiss system) in Stillwater, Oklahoma, under the direction of Frank K. Berry. The Saint Louis Chess Club in St. Louis has hosted the a