In 1363, as Tadahisa bestowed the Provincial Governorship of Satsuma to his third son, Morihisa SHIMAZU (the Soshu family), who was the Assistant Governor of Kazusa Province and the Provincial Governorship of Okuma to his fourth son, Mutsu no kami Ujihisa SHIMAZU (the Oshu family), the Shimada clan split and hostility ensued between them.
1363年薩摩守護職を三男上総介島津師久（総州家）に、大隅守護職を四男陸奥守島津氏久（奥州家）に譲ったため、島津家は分裂し対立することとなる。