Format
The tournament consists of 16 countries participating in 45 matches over a three-day weekend. The 16 teams are divided into four pools of four teams, with seeding determined by finishes in the previous competition in the IRB Sevens World Series. Wins are worth three points, draws two, and losses one. The top two teams from each group progress to the quarterfinals to compete for the Cup (places 1-4) and Plate (places 5-8). The bottom two teams from each group participate in the Bowl (places 9-12) and Shield (places 13-16) competitions.
Through the 2011-12 edition, the sixteen participating teams were the 12 "core" members of the IRB Sevens World Series circuit, along with 4 additional qualifying teams—other teams that qualified multiple times during the 2009-2012 span included Japan, Canada, Uruguay and Guyana. Starting with the 2012–13 season, the number of core teams increased from 12 to 15, with Canada, Spain and Portugal earning the three new slots.
Read more about this topic: USA Sevens