As far as we cannot find any objective materials at that time on 'Soen's achievement' other than what was recorded later by the Nagatani family or the Yamamoto family (Yamamotoyama), taking mere lore as historical fact should be avoided, even to be used as propaganda for industrial purposes.
「宗円の功績」について後年になって当事者である永谷家や山本家（山本山）の記した文献以外に、当時の客観的資料が見いだせない以上、業界の宣伝のためとはいえ、伝承を安易に史実としてしまうことはさけるべきであろう。