Aoki Konyo (青木昆陽)

Konyo AOKI (June 19, 1698 to November 9, 1769) was a Confucianism scholar, and a Dutch scholar in mid Edo period. His name was Bunzo, and Atsushisho.


He was born as the only son of a fish shop owner Hanemon TSUKUDAYA in Odawara City Nihonbashi Bridge (Chuo Ward, Tokyo) in Edo. As a ronin, he adored and studied Confucianism under Togai ITO, who was a Confucianism scholar in Kyoto City. With the sincerity of Enao KATO (or Saemon), who was a yoriki (a police sergeant) in Tadasuke OOKA's group of Edo Town Magistrate's Office, he was made a Loyal Minister in 1733 with Kato's recommendation, and was permitted to read the shogunate books. In 1735, he announced "Banshoko".

The 8th general of the Edo bakufu (Japanese feudal government headed by a shogun) Yoshimune TOKUGAWA had already ordered Konyo to cultivate the known sweet potato as an emergency crop at the famine in West Japan, and make trial pieces in the Koishikawa Medicine Garden (Koishikawa Botanical Gardens), Makuwari-mura village in Chiba District of Shimousa Province (present Makuhari, Hanamigawa-ku Ward, Chiba City, Chiba Prefecture), and Fudodo Village in Yamabe County of Kazusa Province (present Kujukuri-cho, Sanbu-gun, Chiba Prefecture). As a result, it is commented that, since the Great Famine of Kyoho, the cultivation of sweet potato spread in Kanto region and solitary islands, and thus a lot of people's lives were saved in the Tenmei Famine.

In 1736, he became Sweet Potato Goyo-gakari (a general affairs official) and in 1739, he became the superior purveyor of books writings/letters, Konyo left the sweet potato cultivation and became a shogun's retainer. Joining the team of Tadasuke, who was a jisha-bugyo (magistrate of temples and shrines), he investigated the old documents of territory formerly owned by the Tokugawa family—such as Kai Province (Yamanashi Prefecture), Shinano Province (Nagano Prefecture), Mikawa Province, etc.—collected written materials that had been in the family's possession, and researched a book on the family's genealogy. Konyo classified the collected documents, transcribed them and brought them together as "Shoshu Komonjo" (ancient writings about provinces). He returned the originals to the owners, explained the importance of family collection written materials, and admonished preservation. He passed through the Hiban of Momiji-yama Mountain, became a Hyojosho (conference chamber) Confucian, studied Dutch hard, and among his apprentices was Ryotaku MAENO, who was known by "Kaitai Shinsho" (the historic Japanese translation of a Dutch anatomical text).

Though he was appointed shomotsu bugyo (archive commissioner) in 1767, he died of grippe in 1769 at the age of 72.

Though there is a theory that doubts whether the sweet potatoes made by Konyo for trial purposes led directly to the spread in Kanto, as pointed out by Nobuhiro SATO (refer to the "Konyo and Nobuhiro SATO" mentioned later), it is a fact that Konyo had gotten fame because of the sweet potatoes in the same period, and was called 'Sweet Potato Teacher' by future generations. Moreover, in Makuhari where the sweet potatoes were made for trial purposes, Konyo Shrine was built, and Konyo was enshrined as the God of potatoes.

Among his written books were "Idea of Sweet Potato", "Japanese Dutch Translation", "A Brief Introduction to Japanese Dutch Words", "Outline of Economics", "Records of Konyo", "Essays of Straw House", etc.

Spread of sweet potatoes to Kanto

It is generally assumed that, after the making of the sweet potato for trial purposes by Konyo AOKI, the sweet potato cultivation spread to Kanto region. However, concerning this aspect, as pointed out by Nobuhiro SATO and others described later, the following doubts existed.

According to the record of Enao Kato, when Konyo made a business trip to Makuhari Fudodo, he only worked 7 days out of the annual 117 working days, he mainly went to the workshop in the recuperation house and did not really go to the actual locale farm.

Afterward, Konyo left the duty of the sweet potato cultivation spread, and was involved in the old document collection and research on Dutch language.

It is thought that there was a person called Ryouemon HIRANO, an iron worker from Nagasaki who was involved in the sweet potato cultivation with Konyo, and it was HIRANO who did the actual cultivation.

Before Konyo made the trial pieces, under Tadamichi INA (1712 to 1750) of Kanto gundai (a magistrate of Kanto region), the cultivation of sweet potatoes was tried.

There is a document saying that before Kyoho period, the cultivation method of sweet potatoes was also brought to Kanto by way of Shimousa Province Choshi City.
(Shigeo SHIMABARA "Chronological list of the main events for sweet potatoes")

Anyway, because Konyo's trial pieces were the real trial prototype that the shogunate (magistrate of the town) had done, 'Idea of Sweet Potatoes' was published, the spread of cultivation was intended, the shogunate came to regard the sweet potato as an emergency crop after this experimental trial, and this experimental trial led to an epoch-making event for the spread of the sweet potato to Kanto, thus Konyo's status was firmed.

Konyo and Nobuhiro SATO

Nobuhiro SATO criticized that Konyo's sweet potato cultivation method was a 'Careless method' in his book "Six-step method in cultivating plants"and introduced high temperature and humidity seedlings as a harvest method at early time, in contrast to Konyo's method of planting the seed tuber directly on ground. This cultivation method, which was the method of practice until recently in various parts of Kanto, was recorded in many of the farm books in the Kanto region during the late recent period.

Moreover, in "Theory of sweet potato," the story of a sweet potato ronin in the next village Takeishi-son Village of Makuhari (present Hanamigawa-ku Ward, Chiba City) was mentioned as the person who spread the cultivation method of sweet potatos. In the book written by Nobuhiro SATO, there were a lot of original example stories. It is uncertain whether these stories were true. However, it is thought that, the spread of sweet potato cultivation to the Kanto region was after Konyo's trial prototype and a lot of trial and error by a lot of nameless sweet potato teachers.

[Original Japanese]