The Netherlands Eredivisie, established in 1956, is the top professional soccer league in the Netherlands. It is one of the oldest leagues in Europe and has a rich history. The league consists of 18 teams, with each team playing against each other twice in a season. Ajax Amsterdam and PSV Eindhoven are the most successful teams in Eredivisie history, having won the league title numerous times. An interesting fact is that the Eredivisie was the first league to introduce a playoff system to determine the final European qualification spot.