Yoshio Kogyu (吉雄耕牛)

Kogyu YOSHIO (1724 - October 4, 1800) was a Ranpoi (a person who studied Western medicine by means of the Dutch language) and a Japanese-Dutch interpreter (official interpreter of the Edo shogunate) who lived during the middle of the Edo period. His real name was Eisho, and his common name was Teijiro which later changed to Kozaemon. He also called himself Kosaku. He was also known under the name of Kogyu or Yokosai. His father was Tozaburo YOSHIO. The Yoshio family had served as Dutch interpreter for generations.

In 1724, he was born as the first son of Tozaburo in Nagasaki. He started learning Dutch from an early age and became a trainee interpreter at the age of 14 in 1737, assistant interpreter in 1742, and then chief interpreter at the age of 25 in 1748. He was appointed several times Nenban-tsushi (interpreter who served every other year) and Edoban-tsushi (interpreter who accompanied Kapitan [curator of the Dutch trading house of Nagasaki] on their every year's visit to Edo).

While working as interpreter, he learned surgery both from doctors working at the Dutch trading house and from surgery textbooks in Dutch. He was on close terms especially with G. R. Bauer and Carl P. Thunberg (Swedish leading disciple of Carl von Linné), and learned mercury treatment from them to treat syphilis which was epidemic in Japan in those days, and applied it to actual treatments.

He mastered not only Dutch and medicine but also astronomy, geography, and herbalism, and taught those learning to people who aimed to master Rangaku (Western learning). He had many students from all over the country at his private school, Seishukan. The Yoshio Western surgery established by him became popular as a school of Western surgery which could rival the Narabayashi Western surgery established by Chinzan NARABAYASHI.
It is said that as the second floor of Yoshio's residence was decorated with furniture imported from the Netherlands, it was called 'Dutch room.'
The residence also had plenty of Dutch plants and animals in the garden and became a famous place in Nagasaki. He hosted the so-called 'Dutch New Year' party in the New Year by Western calendar (the solar calendar).

There were many of Rangakusha (a person who studied Western sciences by means of the Dutch language) and doctors, who visited Kogyu (Yoshio)'s residence or leaned at Seishukan, and most of the leading Rangakusha at the time, including Konyo AOKI, Genjo NORO, Gentaku OTSUKI, Baien MIURA, Gennai HIRAGA, Shihei HAYASHI, and Kokan SHIBA, had contact with him and gained much knowledge from him. According to Gentaku OTSUKI, Yoshio had more than 600 students. Kogyu (Yoshio) had close relations with Ryotaku MAENO and Genpaku SUGITA among others, and praised their achievements by contributing a foreword for their book "Kaitai Shinsho" (New Book of Anatomy). After returning to Edo, Gentaku hosted Edo-Dutch New Year party at his private school Shiran-do as well.

In 1790, he was deprived of his post as inspector of Dutch interpreters and sentenced to a five-year house confinement as he had been involved in the mistranslation regarding a camphor export. After return-to-work, in 1796, he was appointed to the post of instructor of Western studies.

In 1800, he died of illness at his residence in Hirado-cho (present Edo-machi, Nagasaki City). He died at the age of 77. His posthumous Buddhist name was Kogyu KANDEN.

His translated works included "Waran-ryu (Komo-ryu) Koyaku-ho" (Dutch [Western] Salve Prescription), "Seikotsu Yoketsu" (Summary of Osteopathy), "Plenck Baiso-hen" (Plenck's Book on Syphilis), and "Ineki Happi" (Excretory Mechanism) (published after the death of Yoshio but based on his oral statements and later retranslated and published by Ransai EMA under the name of the "Goeki Shinpo").

He showed outstanding achievements both in the area of interpretation and medical science, and his sons, Eikyu YOSHIO as doctor and Gonnosuke YOSHIO as interpreter, succeeded Yoshio's works. Gonnosuke's students included Choei TAKANO. There is his critical biography "Edo no Ranpoigaku Kotohajime - Oranda Tsushi YOSHIO Kozaemon Kogyu" (The Beginning of Dutch Medicine of the Edo period - Dutch translator, YOSHIO Kozaemon Kogyu) (Maruzen Library, 2000) written by Kazuo KATAGIRI.

[Original Japanese]