In 1582, following the murder of his nephew and head of the Isshiki clan, Yoshisada ISSHIKI, by Yusai HOSOKAWA, he moved into Yuminoki-jo Castle and took over the role of clan head.
1582年、甥で一色氏の当主であった一色義定が細川幽斎に謀殺されたため、弓木城に入って一色氏の家督を継いだ。