The latter learned Western studies by associating with scholars of Western studies like Gentaku OTSUKI, and left many valuable books, such as the introduction of "Rangaku-kaitei" (a guide to foreign languages), "Taisei-yochizusetsu" (a foreign topography), and "Kokon-senka-kagami" (a reference book of coins).
後者は大槻玄沢ら蘭学者やオランダ商館長（カピタン）と交遊を持って蘭学を研究し、『蘭学階梯』の序文や『泰西輿地図説』、『古今泉貨鑑』など、多くの貴重な著作を残した。