In the Sengoku Period (period of warring states), having the territories in Hitokubota and Yoshino, Kando County, Izumo Province as well as in Otakitago, Ano County, Iwami Province, Genzaemon no jo ISHIBASHI and Shinzaemon no jo ISHIBASHI, possibly of the Ishibashi clan, both of whom became the influential retainers of the Sawa clan, a local lord, and were appointed as head of merchants of Unshu (= Izumo County), emerged from the Shimane Ishibashi clan.
なお、戦国時代には、出雲国神門郡一窪田・吉野や石見国安濃郡太田北郷等に所領を持ちつつ、国人佐波氏の有力家人となり、雲州商人司に任ぜられた石橋氏の一族と思しき石橋源左衛門尉や石橋新左衛門尉が「島根石橋家」に登場する。