(1929-) Japanese socialist politician, leader of the Social Democratic Party of Japan (SDJP), formerly the Japan Socialist Party (JSP), 1986–1991. The country's first female major party leader, she was largely responsible for the SDJP's revival in the late 1980s. Her resignation followed the party's crushing defeat in local elections April 1991.
Doi was a law lecturer before being elected to the house of representatives 1969. She assumed leadership of the JSP at a low point in the party’s fortunes and proceeded to moderate and modernize its image. With the help of “housewife volunteers” she established herself as a charismatic political leader, and at a time when the ruling Liberal Democrats were beset by scandals, the JSP vote increased to make Doi the leader of an effective opposition.