All flights typically begin play on Wednesday, two days before the main NABC events.
[1] The United States Bridge Association, established by Ely Culbertson and his staff, conducted a Grand National Team-of-Four championship from 1934 to 1937 (the lifetime of the organization before merger created the ACBL).
[citation needed] The extended, grass-roots tournament was re-established in 1973, when about 1500 teams participated.
[2] Initial stages were contested in the 25 geographically defined ACBL Districts.
The Zonal stage was eliminated in 1985; since then every District champion qualifies for the final at the Summer NABC.