In the Hockey Series all countries can participate, except those who dispute the Hockey Proleague. The 1st round in 2018 do not play the 9 teams with better rankings for those enrolled in the Open Series
The 2nd round are 3 regional events with 8 teams each of these 8 teams, 3 would be exempted from the 1st round due to its ranking and 5 from the 1st round.
The first 2 of each regional event classified for the Olympic Qualification Events (in total 6)
If Japan did not earn the Asian continental 12 teams participate in the Olympic Qualification Events: 4 teams from the pro-league-final, +6 Hockey Series + 2 teams of the world ranking. Then there would be 6 qualifiation matches in in the Olympic Qualification Events
If Japan earn the Asian continental 14 teams participate in the Olympic Qualification Events: 4 teams from the pro-league-final, +6 Hockey Series + 4 teams of the world ranking Then there would be 7 qualifiation matches in in the Olympic Qualification Events
All the information is on https://clasificacionolimpica2020.blogspot.com.es/search/label/Hockey