Yoshio Kōsaku

Who They Were

Yoshio Kōsaku (吉雄耕牛) was a physician, translator and scholar of rangaku (蘭学, らんがく) — "Dutch studies", the body of European learning that entered Japan through the Dutch trading post at Nagasaki during the Edo period (1603 – 1868). He was the chief Dutch translator in Nagasaki and, from roughly 1770 to 1800, the principal mediator between the Dutch community on the artificial island of Dejima and the Tokugawa shogunate. He was born in Nagasaki in 1724, the ninth year of the Kyōhō era (享保, きょうほう), and died in the same city on 4 October 1800.

His family was one of five samurai households that the shogunate supported as hereditary official Dutch interpreters, a position that made the Yoshio household a permanent piece of the state's information infrastructure. Kōsaku inherited that role and expanded it: he vetted imported documents for prohibited Christian material, kept the shogunate informed of political developments abroad, and wrote prolifically on what he learned. He has been described as perhaps the most knowledgeable person in Japan about the West in his day.

Life and Career

Kōsaku's working life was organised around the annual rhythms of the Dutch East India Company. Company officials were required to travel from Nagasaki to Edo to pay their respects to the shogun, and Kōsaku accompanied them on these missions and on other official business, serving as interpreter, escort and intermediary. The journey gave him a view of the country that few Japanese of his rank ever had, and he used it. In 1774, travelling to Edo with Company officials, he wrote an account of the shogunal capital that praised it as a model the rest of the nation ought to imitate while criticising its inhabitants as interested only in profit. That text appeared as part of the preface to the first integral translation of a European book to be published in Japan.

At home in Nagasaki he ran a Dutch-style medical school, which at times enrolled as many as six hundred students, and he mentored a generation of rangaku scholars, among them Sugita Genpaku. He maintained a Dutch-style house that became something of an attraction in its own right. The physician Tachibana Nankei, who stayed there, recorded its features in his diaries: a Dutch lie-down bathtub, a Western-style staircase painted green rather than the bare ladder-like stairs of a Japanese home, window drapes, and chairs that Nankei found grueling to sit on after a lifetime on tatami floors. Kōsaku also collected European books, paintings, eyeglasses and mirror paintings.

Visitors of every kind — scholars, officials, artists — made a point of calling on him when they passed through Nagasaki. The ranga painter Shiba Kōkan visited in 1788, stayed a few nights, and was given a tour of Dejima. The portrait Kōkan painted on that occasion, part Western oil painting and part Japanese ukiyo-e, survives.

Why They Matter

Kōsaku stood at the narrowest point of Japan's contact with Europe. Under the Tokugawa policy of limited foreign exchange, the Dutch at Dejima were effectively the country's only window onto Western science, medicine and politics, and the interpreters were the only people who could open it. Because Kōsaku held that post for three decades and wrote constantly, he shaped what educated Japanese could know about the outside world.

His thirty-nine works, mostly on rangaku subjects, circulated among scholars who could not travel to Nagasaki. His criticism of Edo, embedded in a preface to a translated European book, belongs to a broader current of rangaku writing at the time that quietly challenged two assumptions: that Europeans were barbarians, and that China was the only model of enlightened civilisation. That argument, made in prefaces and travel notes rather than treatises, prepared the ground for the wider adoption of Western learning in the following century.

The Name in Japanese

The name is written 吉雄耕牛. It is read よしお こうぎゅう in kana, and romanised as Yoshio Kōgyū — the form used in the encyclopedia summary above, alongside the alternative reading Kōsaku for the given name.

The surname comes first, as is standard in Japanese:

• 吉 — read yoshi here. It means "good fortune" or "luck", and it is a common element in Japanese surnames and place names.
• 雄 — read o here. It means "male" or "brave, mighty". Together, 吉雄 is the family name, borne by the line of hereditary interpreters.

The given name follows:

• 耕 — read kō here. It means "to plough" or "to cultivate". It is the character used in words about farming and, by extension, about steadily working at a discipline.
• 牛 — read gyū here. It means "cow" or "ox". In combination with 耕, the name evokes the image of an ox at the plough: patient, unglamorous, sustained labour.

The reading Kōgyū is the Sino-Japanese one, used in formal and scholarly contexts. Kōsaku is the alternative reading of the same characters, and it is the form under which he appears in many Western-language references. A reader encountering either name in a bibliography is looking at the same man.

Legacy

Kōsaku's students carried rangaku out of Nagasaki and into the intellectual life of the shogunate's last century. Sugita Genpaku, who studied under him, went on to work on the anatomy translation that helped establish Western medicine in Japan. The medical school Kōsaku ran, with its hundreds of enrolments, functioned as a pipeline from a single Nagasaki household to physicians and scholars across the country.

The material traces of his household — the green staircase, the bathtub, the chairs that Tachibana Nankei complained about — survive mainly in the diaries of visitors, and his likeness survives in Shiba Kōkan's portrait. His thirty-nine written works and the documents he vetted and translated remain the record of a career spent at the point where Tokugawa Japan met the Dutch trading mission, and of a scholar who used that position to argue that his country had something to learn from the West.