In various forms the AGA has held a national championship since 1959. The US Open currently acts as the championship tournament, and it is held annually at the US Go Congress. The US Open welcomes all comers, regardless of playing strength, age, gender or nationality, and is the largest tournament held in North America. The tournament is also used as the selection tournament to decide the AGA's representatives to the World Amateur Go Championship and the Korea Prime Minister Cup.

The US Open was preceded by the US Championship, which split into East Coast and West Coast tournaments; the winners would play to determine the national champion. When the US Go Congress became a national-scale event, the US Open was held as a separate five-round tournament over the final weekend of the Congress. In 1992, the US Open merged with the Congress championship and became a six-round championship tournament stretching over the entire week.

History