He conducted investigation and research on histories of Japanese commerce and industry, as well as industrial policy, through literatures left in the former bakufu (Japanese feudal government headed by a shogun) or houses of feudal lords, and visits to merchant houses, etc.
旧幕府や諸侯家に遺された文献や商家などを回って日本の商工業及び産業政策の歴史に関する調査・研究事業を行う。