The Japan Diamond Softball League (JD.League) is a Japanese women's softball league that consists of 16 teams (8 in the East Division and 8 in the West Division).

In 1994, the league's First Division expanded from 8 to 12 teams and adopted a postseason with the page playoff system.

The opening game of the JD.League was held between Bic Camera Takasaki Bee Queen and Toyota Red Terriers on March 28, 2022.

A player who is signing a professional contract is only a small portion.

[24] Following the conclusion of the regular season, seven teams compete in the four-round postseason tournament (the two-round Playoffs and the two-round Diamond Series) with a single-elimination stepladder format.

The Bic Camera Takasaki Bee Queen won the most championships with 14 titles.