Naka Tenyu (中天游)

Tenyu NAKA (male, 1783 - April 23, 1835) was a Doctor of Dutch medicine and Dutch scholar. His names were Tamaki, Kosuke and Toru. Azana (adult males nickname) was Kanchu. His second names or aliases were Tenyu, Shishisai (思思斎 or 思々斎).

Tenyu was born in Tango Province. His father was a Confucian and a doctor (concurrent), 上田河陽, and later, he put Tenyu up for adoption as an successor of a relative on his mother's side, the Naka family.

At the age of 22, he went to Edo to enter Gentaku OTSUKI's private school called Shiran-do, and after that, he followed one of the best four of Shiran-do, Sanpaku INAMURA who moved to Kyoto, and studied Western learning and Western medical science under him. When his teacher Sanpaku became sick, Tenyu who was appreciated by Sanpaku got married with his daughter, Sada. After the death of Sanpaku, Tenyu moved to Osaka with his wife to open clinic and became a medical practitioner. However, Tenyu preferred Kyurigaku, philosophy of nature (science, natural philosophy) rather than medical science. While he left management of the clinic to his wife, he became involved in Western learning.

After that, when Tenyu heard the reputation about private school Shikan-do founded by one of the best four of Shiran-do, Sokichi HASHIMOTO, he became a pupil of Sokichi HASHIMOTO. At a time when Western learning was held in contempt as bangaku (barbaric study), public opinion was strongly against Dutch scholars. With the Osaka Kirisitan Incident and Siebold Incident as a start, the crackdown toward Dutch scholars was becoming more violent, and Tenyu's teacher, Sokichi also closed the school and lived in seclusion temporarily, however, Tenyu continued to be confronted with an opposition in order to hand on the torch of Western learning in Osaka in unbroke transmission down the ages.

When the Tempo Famine occurred in 1832, he worked hard to it, however, he died on April 23, 1835, in the middle of the famine. He died at the age of 53.


Sokichi HASHIMOTO, who made a great effort to allow Western learning to take root in the land of OSAKA, was called the founder of Western learning, while Tenyu also earned his place in history with Sokichi as one of the person who livened up Western learning in Osaka.

Moreover, besides learning at Shikan-do, he founded a private school, Shishisaijuku, at the age of 35, and produced Koan OGATA and Hyakki OKUGAWA and others. After the death of Tenyu, in Koan's time, who followed the last wishes of Tenyu, Western learning in Osaka exceeded that in Edo and prospered as the most popular place of Western learning in Japan.

Moreover, in the field of literary work, Tenyu wrote the book Inritsu (引律) by adding his opinion to the book of astronomy (the book of Kyurigaku) titled 'Rekishoshinsho' written by John KEIL and translated by Tadao SHITSUKI. Tenyu, who was also well versed in Wasan (Japanese mathematics), pioneered a new field in Western learning that tended to place a disproportionate emphasis on medical science and left many literary works.