平Gennai Hiraga (1728～1779), in the middle of the Edo period, showed his great talent in various fields as an inventor, an author of Edo joruri, a Dutch scholar, a ceramic artist, a painter, a herbalism scholar (pharmacologist) and so on. Especially, he is well known as the restoration of an electrostatic generator ‘Erekiteru’ and the suggestion taken root in Japan for eating an eel on the Midsummer Day of the Ox.
Gennai Hiraga was born as the third son in Shiraishi clan in Shidoura, Samukawa County, Sanuki Province (present-day Shido, Sanuki City, Kagawa Prefecture). His father was Shiraishi Mozaemon, his mother was from the Yamashita clan, and he had many siblings. The Shiraishi clan was a family of 'foot soldier' called 'ashigaru' of the Takamatsu Domain. Although the Shiraishi clan was once a local ruling family of Saku County, Shinano Province, according to the “Kouyou Gunkan”, the clan was defeated at Unnokuchi castle in Saku Country by Nobutora Takeda in Kai Province in November, 1536 during the Period of Warring States that was when Genshin Hiraga was the clan head. Then those survived moved to Shiroishi City, Mutsu Province, and served the Date clan under the renamed family name, Shiroishi. Later, they moved to the Shikoku region following the Lord of the Iyo Uwajima Domain, and returned to farming. He changed his family name Shiraishi to his ancestral family name Hiraga in Gennai’s time. Gennnai studied Herbalism under doctors in the feudal domain from 13 years old and learned Confucianism.
He went to Nagasaki in 1752 to study Herbalism, Dutch, medicine, an oil painting and so on for a year. After studying in Nagasaki, he resigned from his duties to the feudal domain and abandoned the headship of the family by adopting his younger sister's husband. He studied in Osaka and Kyoto, and in 1756 he went to Edo and became a pupil of the herbalism scholar Genyu Tamura (Ransui), whereupon he studied herbalism. He was also admitted to the Hayashi family in order to learn Chinese classics, and he boarded at the Sacred Hall. In his second period of study in Nagasaki, he learned mining and refining technology.
He discovered a mineral deposit in Izu in 1761, becoming a broker of products. He frequently held product expositions and he was recognized by a member of the shogun's council of elders 'roju', Okitsugu Tanuma, during this period.
Although he was reappointed as a vassal of the Takamatsu Domain in 1759, he resigned in order to go back to Edo in 1761. At that time, he was broken up by the Takamatsu Domain. Afterward, his serve to other clans including an appointment as a retainer of the shogunate was prohibited. He opened the medicine fair 'Toto Yakuhinkai' in Yushima, Edo as the fifth product exposition in 1762. He became well known in Edo, and associated with Genpaku Sugita and others.
He started to develop a mine at Nakatsu-gawa River in Kawagoe Domain from 1766 for a request of Suketomo Akimoto in Musashi-Kawagoe Domain and found asbestos. He also taught making charcoal in the Chichibu district and passage construction at the Ara-kawa River. Near to Nakatsukyo, Okuchichibu, a building that Gennai designed and stayed for a long time, remains as "Gennaikyo" in the present day. In 1776, he fixed and restored an electrostatic generator 'Erekiteru' that he had obtained in Nagasaki.
He moved to the residence of Hashimoto-cho in the summer of 1779. When he contracted for house reconstruction of a Japanese feudal lord, he killed two master carpenters because of drunken by making a mistake that his blueprint was stolen. He was imprisoned on November 21th and he died of tetanus on December 18th. It is said that the person who took his dead body in prison back was Hedutsu Tosaku, a kyogen actor.
Died at the age of 52. His funeral was held by Genpaku Sugita and others without Gennai's body or a gravestone, since they were not permitted to have them by the shogunate. However, there have been various views in later years, such as that he killed the carpenter Kyugoro Akitaya and that he escaped, dead only on a paper, and died a natural death under the protection of Okitsugu Tanuma or Takamatsu Domain (Takamatsu Matsudaira clan, his former load ). These views are still uncertain.
Hiraga Gennai Memorial Hall A memorial hall located at his birth place, Sanuki City, Kagawa Prefecture. He spent his youth there before leaving for Edo.