The Zealand Association Football Championship (Danish: Sjællandsmesterskabet, SM) was introduced a week after the association's foundation in 1902 and was played in a cup format until actual league formats organized on a double round-robin basis including promotions and relegations were introduced in 1927 with the highest ranking division being named Mesterrækken (or SBUs Mesterrække to distinguish it from the other regional leagues).
[1] At the annual general assembly in 1927, the decision of introducing an actual league format for the best member teams was passed, creating the Mesterrækken (SBU level 1) and the A-rækken (SBU level 2) with promotions and relegations in a double year-long format (autumn-spring) under the auspices of the football association.
[5][6] Starting from the 2015–16-season, the best men's league would be split into two geographically organized groups with 12 teams, where the group winners are each secured a direct promotion spot to Denmark Series, while the runners-up play an additional single match on a neutral field for a third promotion spot to the fourth level in Danish football.
[5][6] The losing team will enter into a play-off match against one of the league runners-up from the other regional associations.
[5] The runners-up in both group enter a play-off match against each other on a neutral playing field for the right to enter the Denmark Series, while the losing team will get an additional chance by playing one extra play-off match against a league runner-up from another regional association.