The dictionaries consulted by Hepburn
Hepburn wrote in the preface to the Waei Gorin Shūsei:
In compiling this work the author has labored under the very great difficulty of having had little to assist him from the works of predecessors in the same field. The only works of the kind within his reach were the small vocabulary of Dr. Medhurst published in Batavia in 1830; and the Japanese and Portuguese Dictionary published by the Jesit missionaries in1603. His principal dependence, however, has been upon the living teacher, so that he feels himself alone responsible for every thing in the work.
The Meiji Gakuin University Library owns a copy of the Medhurst dictionary (published in 1830) referred to above, signed by Hepburn and containing pencil annotations.
However, despite many years of searching every crevice of the university, The Japanese and Portuguese Dictionary (Nippo Jisho) is not yet to be found. There are 264 years between the two dictionaries: Hepburn's Waei Gorin Shūsei was published in 1867 (Keio 3), while The Japanese and Portuguese Dictionary was published in 1603 in Nagasaki with a Jesuit missionary-owned printing press. Given this context, where did Hepburn get hold of a copy of The Japanese and Portuguese Dictionary?
Hepburn landed in Kanagawa in October 1859 (Ansei 6), having also stopped in other ports, including Singapore and Shanghai, as they journeyed from the USA around the Atlantic and Indian Oceans. Moreover he was working as a missionary doctor in China. He appears to have learned kanji through his knowledge of the Chinese language. Was it during his time working as a missionary doctor that he discovered The Japanese and Portuguese Dictionary somewhere? Nevertheless, there currently remain only five known copies of The Japanese and Portuguese Dictionary, making it a rare book. Even then, a chance to look through the dictionary was extremely hard to come by.
The answer to our question has long been a mystery. However, several discoveries have been made during the creation of this archive.