Based on this theory, the description that the natsume appeared in a tea book "Genryu Chawa" (tea book written by Chikushin YABUNOUCHI) in the Genroku period, as derived from a wooden hikiya canister owned by chajin (master of the tea ceremony), has also lost its credibility.
またこの説により、元禄時代の茶書『源流茶話』（藪内紹智）に記載されている棗が茶入の挽屋を転用したものであるという記述も信憑性を失っている。