Teams in the Eastern League generally play an 80-game schedule every year.
[3] The Eastern League restarted in 1961 with five teams:[1] in the interim the Daiei Stars and the Takahashi Unions (formerly the Tombo Unions) had merged into the Daiei Unions, who in turn merged with the Mainichi Orions to ultimately form the Daimai Orions (now known as the Chiba Lotte Marines).
From that point until the year 2000, all Japanese minor league teams used the same name as their NPB parent club.
In 2005 the Tohoku Rakuten Golden Eagles were formed to join NPB, and their farm team became part of the Eastern League as well.
The independent Niigata Albirex Baseball Club was added to Eastern League for the 2024 season.