The first league format competition in the second level of Finnish football was called Suomensarja, which was founded in 1936. In the autumn of 1969, the Finnish football underwent a league system reform, and the Suomensarja was renamed II divisioona, or 2nd Division, with regional sections.
In 1973, this level of football in Finland became nationwide, and the new name was 1. divisioona (‘First Division’), present-day Ykkönen (likewise ‘First Division’).
Before the inauguration of the Suomensarja, there had been, in 1930–1935, special qualification matches for the right to play in the Mestaruussarja, ‘Championship series’. A proper league format competition on this level began in 1936 with the 1936 Suomensarja.
Like the Veikkausliiga, the first division is played mainly during the summer. It comprises 10 clubs, all of whom play three matches against all other clubs in the division. The winner of the Ykkönen qualifies directly for promotion to Veikkausliiga. The bottom 2 clubs are directly relegated to Kakkonen.