As the Ochi-kanze family, which Sosetsu's older brother Suruga Juro Dayu became the head of, was founded by Ochi-kanze Dayu, the first of Zeami's legitimate grandchildren (Fujiwaka-kanze Dayu), it possessed a larger amount of precious documents that had been handed down from Zeami than the head of the Kanze family did.
兄・駿河十郎大夫の継いだ越智観世家は、世阿弥の嫡孫・初代越智観世大夫（藤若観世大夫）に始まる家であり、観世宗家にも勝る貴重な世阿弥伝書を多数所蔵していた。