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The modern format for the World Championship features a minimum of 40 teams: 16 teams in the main championship group, 12 teams in Division I and 12 teams in Division II. If there are more than 40 teams, the rest compete in Division III.
From 1998 to 2011, the teams were divided into four groups and played each other in a round robin format preliminary round, and the top 3 teams in each group advance into the qualifying round. The qualifying round is another round of group play with two groups of six, with the top four teams in each group advancing into the knockout playoff stage. The bottom four teams in the preliminary round played in another group as well; this group determined relegation. After a round-robin format, the bottom two teams were usually relegated to play in Division I the following year.
Between 1998 and 2004, the IIHF held a "Far East" qualifying tournament for Asian teams with an automatic berth in the championship division on the line. Japan always won this tournament, but finished last at every World Championship except in 2004, when they finished 15th. The IIHF discontinued the qualifying tournament following the 2004 tournament, and Japan was relegated to compete in Division I.