Since in the late 1930s only two teams were promoted to the Ekstraklasa, and there were as many as fourteen regional champions, there was a complicated system of playoffs.

Firstly, winners of neighbouring A Classes played each other, and in the final stage, four teams competed, with two top sides winning the promotion.

Second-level league was first created for the 1949 season, and was split into northern and southern sections, each comprising 10 teams.

Officials from Gdańsk promoted the creation of the league, but this idea was opposed by the delegates from the most powerful regions of Polish football: Kraków, Łódź, Upper Silesia and Warsaw.

On 19 February 1949, Polish Football Association decided to expand the league to 20 teams, divided into northern and southern groups.

To determine a winner of the 1949 season of the second division, Górnik had to play Garbarnia in three extra games (4–2, 0–2 and 4–3).

Teams placed 15-18 were automatically relegated to II liga (West or East), while the top two finishers were promoted to the Ekstraklasa.