Just did some looking around at the softball championships for the different divisions and it seems odd to me the way each one does it:
Div I - actually called the World Series, others cannot use that name. 64 teams. Actually seed the top 16 teams and brackets follow that through to the World Series. Championship is a best 2 of 3.
Div II - They play their softball championship with a regional and super regional format. 64 teams. They rank the 8 teams inside a super regional with teams 1,4,5 and 8 in one regional and 2,3,6 and 7 in another. Teams in regionals grouped by location. Championship game is one game winner take all.
Div III - They are now playing a regional and super regional format. 62 total teams this year (based on number of teams playing d3 softball so number can change yearly). Teams assigned to regionals based on their zip code (limited travel over 500 miles). Championship bracket predetermined beforehand. Championship is a best 2 of 3.
Seems odd there is so much variance between how each is handled.