It is thought that sekitai were made to be stiff only in modern times because the sekitai that is a secret treasure of Asuka-jinja Shrine is so soft that it can be rolled for storage.
石帯の硬化は近世に入ってからのようで、室町時代の阿須賀神社神宝の石帯は丸めて保存できるほどやわらかい。