Excerpts from Books and Wikipedia
"The Southern Court (…) were a set of four emperors (Emperor Go-Daigo and his line) whose claims to sovereignty during the Nanboku-chō period spanning from 1336 through 1392 were usurped by the Northern Court. This period ended with the Southern Court definitively losing the war, and they were forced to completely submit sovereignty to the Northern Court. This had the result that, while later Japanese sovereigns were descended from the Northern Court, posterity assigns sole legitimacy during this period to the Southern Court.
The Southern descendants are also known as the "junior line" and the Daikakuji line (…), Daikaku-ji being the cloistered home of Go-Uda, a Southern ruler. Because it was based in Yoshino, Nara, it is also called the Yoshino court." [Wikipedia]