The tournament proper begins with a group stage of 40 teams, divided into ten groups. Seeding is used whilst making the draw for this stage, with teams from the same country not being drawn into groups together. The group stage is divided into two zones; the first zone is the five East Asian groups and the other zone is the five West Asian groups. Each team meets the others in its group home and away in a round-robin format. The winning team and the runners-up from each group then progress to the next round.