He was born in a mountain village at Kanzaki in Hizen (Saga), the son of a family serving a shrine. The family was not well off, but he was a boy who loved study. He first learned Chinese-style kanpō medicine under a local doctor and set out on the path to making his living as a physician.
Around this time he went to Nagasaki, studied Dutch and came into contact with ranpō, Western medicine. Strongly drawn to Western medicine, which explained the body's structure on the basis of dissection, Genboku resolved to switch from kanpō to ranpō. This choice would determine the rest of his life.
He studied the latest Dutch medicine at the Narutaki school opened by the German physician Siebold, who had come to Nagasaki. He also attended examinations of real patients and operations, deepening his medical knowledge. Mixing with young scholars gathered from all over Japan was also a great asset.
When Siebold accompanied the head of the Dutch trading post on his journey to pay respects to the shōgun in Edo, Genboku went to Edo with them and stayed there. He opened a practice in Edo as a ranpō doctor and made his name while mixing with fellow students of Dutch learning.
It was discovered that Siebold had tried to take home a map of Japan that was forbidden to leave the country, and those involved were punished one after another (the Siebold Incident). Danger loomed for Genboku as Siebold's pupil, but he escaped punishment and was able to continue his work in Edo.
He opened the ranpō school Shōsendō in Shitaya, Edo. Many young people from across Japan enrolled to study Dutch and Western medicine, and the school trained many doctors active from the end of the Edo period into Meiji. Genboku was adopted into the Itō family, physicians of the Saga domain, and took the name Itō Genboku.
He was taken into service as personal physician to Nabeshima Naomasa, lord of Saga. Naomasa was known as a lord eager to adopt Western technology, and Genboku worked hard to introduce Western medicine to the domain. This tie with his home domain would lead to his later great work.
To prevent smallpox, which was then taking many lives, Genboku advised the Saga domain to obtain cowpox vaccine for vaccination. The vaccine obtained through the Dutch trading post worked, and it spread from Nagasaki to Kyoto, Osaka and then Edo, saving the lives of many children.
Joining forces with fellow ranpō doctors, he opened a vaccination center at Otamagaike in Kanda, Edo. The same year, when the shōgun Tokugawa Iesada fell seriously ill, he was among the first ranpō doctors chosen as an inner physician to treat the shōgun. It was a turning point at which ranpō joined the shogunate's medicine, until then monopolised by kanpō doctors.
The vaccination center burned down but was rebuilt, became an official shogunate institution and was soon renamed the Institute of Western Medicine, teaching Western medicine and performing dissections and vaccinations. Genboku took part in running it. This line of development would lead to the later University of Tokyo Faculty of Medicine.
He became the first ranpō doctor promoted to hōin, the highest rank for a physician, standing at the summit of ranpō medicine in name and reality. When the head of the Institute of Western Medicine died, he also helped bring Ogata Kōan of the Tekijuku in Osaka to Edo as successor.
Amid conflict with Matsumoto Ryōjun, the new head of the Institute of Western Medicine, and others, he lost his post as inner physician. Although he later recovered part of his standing, he never returned to the front stage. Even so, his achievement in rooting Western medicine in Japanese medicine remained secure.
Having witnessed the new Meiji era, he died at 70. His grave is in Yanaka, Tokyo. Starting as a village boy, Genboku spread vaccination, saved many lives and established the standing of ranpō doctors; he is regarded as one of those who laid the foundations of modern medicine in Japan.
Philipp Franz von SieboldOgata KōanTerashima Munenori
Tanaka HisashigeTokugawa NariakiEgawa HidetatsuKawaji ToshiakiraTakano ChōeiTownsend HarrisFujita TokoShimazu Nariakira
People of the Edo period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.