Tenmonkata (天文方)

Tenmonkata was a scientific research institution established by the Edo bakufu (Japanese feudal government headed by a shogun). It was principally in charge of making a calendar.

The job of making a calendar was originally done by Onmyoryo (Bureau of Divination) of the Imperial Court. After Harumi SHIBUKAWA replaced Senmyo Calendar by Jokyo Calendar in 1684, the bakufu established Tenmonkata under jisha-bugyo (magistrate of temples and shrines) and Harumi became Tenmonkata ('Tenmonshoku' is also used for the position title) on January 5, 1685. Since then, the job of making a calendar was done by bakufu's Tenmonkata. Tenmonkata was placed under the supervision of wakadoshiyori (a managerial position in Edo bakufu) on March 4, 1747. Its horoku (stipend) was 100 hyo (6,000kg) of rice and yakuryo (executive allowance) of five to ten fuchi (the equivalent of five to ten men rice stipend) was added.

The position of Tenmonkata was basically inherited based on the hereditary system, but persons who were well-versed in astronomy were sometimes added or allowed to inherit the position by adoption. As a result, members of eight families were appointed to the position during the end of Edo period; namely Shibukawa family, Ikai family, Nishikawa family, Yamaji family, Yoshida family, Okumura family, Takahashi family and Adachi family. However, some families became extinct and the descendants of Joken NISHIKAWA (his son Masayoshi NISHIKAWA was appointed to Tenmonkata by Yoshimune TOKUGAWA) and Yoshitoki TAKAHASHI didn't continue to inherit the position until the end of Edo period. Finally, only Shibukawa family, Yamaji family and Adachi family survived until the end of Edo period. Bansho-wage Goyo (government office for the translation of western books) was established in 1811 according to the proposal of Kageyasu TAKAHASHI, and it continued to exist until Bansho Shirabesho (government office for the study of western books) was established in 1858. In addition to the job of making a calendar, Tenmonkata was also in charge of astronomy, surveying, topography and the translation of western books during the last stage of Edo period. It was one of the origins of present Tokyo University.

Families of Tenmonkata
Shibukawa family
The family became Tenmonkata in 1684 thanks to Harumi SHIBUKAWA's contribution to the revision of calendar. Members of the family inherited the position until the end of Edo period while repeating adoptions.

Harumi SHIBUKAWA - Hisatada SHIBUKAWA - Hirotada SHIBUKAWA - Hironari SHIBUKAWA - Noriyoshi SHIBUKAWA - Mitsuhiro SHIBUKAWA - Masakiyo SHIBUKAWA - Masateru SHIBUKAWA - Kagesuke SHIBUKAWA - (Takanao SHIBUKAWA) - Sukekata SHIBUKAWA - Yoshinori SHIBUKAWA

Ikai family
Masakazu (Toyojiro) IKAI, okachi (a lower class samurai), became the assistant of Hirotada SHIBUKAWA in 1716 and he was appointed to Tenmonkata in 1736. Masakazu died in 1741 and the family extinguished since he has no successor.

Nishikawa family
Masayoshi NISHIKAWA, a son of Joken NISHIKAWA, an astronomer in Nagasaki, was appointed to Tenmonkata in 1746, and his descendants inherited the position for two generations.

(Joken NISHIKAWA) - Masayoshi NISHIKAWA - Tadataka NISHIKAWA
Yamaji family
Nushizumi YAMAJI became the assistant of Noriyoshi SHIBUKAWA and Masayoshi NISHIKAWA at the time of Horyaku calendar revision (Horyaku Calendar), and he was appointed to Tenmonkata in 1764. Although the second Yukiyoshi YAMAJI was not appointed to Tenmomkata, the third Tokufu YAMAJI and his descendants inherited the position until the end of Edo period. Aizan YAMAJI, a great grandson of Tokufu, is known as a novelist.

Nushizumi YAMAJI - (Yukiyoshi YAMAJI) - Tokufu YAMAJI - Yukitaka YAMAJI - Akitsune YAMAJI - (Akiyoshi YAMAJI) - (Aizan YAMAJI)

Yoshida family
Nagahide SASAKI (later Hidenaga YOSHIDA) became the assistant of Tadataka NISHIKAWA, a son of Masayoshi NISHIKAWA, at the time of Horyaku calendar revision (Horyaku Calendar). He was appointed to Tenmonkata in 1764 and was ordered to revise Horyaku Calendar. Members of Yoshida family inherited the position of Tenmonkata until the end of Edo period.

Hidenaga YOSHIDA - Hidenori YOSHIDA - Hidekata YOSHIDA - Hideshige YOSHIDA
Okumura family
Kunitoshi OKUMURA became the assistant for making a new calendar in 1765 and was appointed to Tenmonkata in 1787. No one succeeded to him.

Takahashi family
Yoshitoki TAKAHASHI was appointed to Tenmonkata in 1795. Takahashi family extinguished when Kageyasu TAKAHASHI, the oldest son of Yoshitoki, died in prison because of his involvement in Siebold Incident. However, his second son Kagesuke SHIBUKAWA became the adopted son of Shibukawa family.

Yoshitoki TAKAHASHI - Kageyasu TAKAHASHI
Adachi family
Nobuakira ADACHI became the assistant of Yoshitoki TAKAHASHI at the time of Kansei calendar revision (Kansei Calendar) and was appointed to Tenmonkata in 1835. Two generations of the family served as Tenmonkata until the end of Edo period.
Nobuakira ADACHI - (Nobuyori ADACHI) - Nobuyuki ADACHI

Observatory of Tenmonkata

Shitendai (astronomical observatory) was established at Ushigome Wara-cho in 1685, a year after Harumi SHIBUKAWA was appointed to Tenmonkata. It was moved to Honjo (Sumida Ward) in 1689, and to Kanda Surugadai in 1701. After the death of Harumi, it was moved to Kanda Sakuma-cho in 1746, to Ushigome Fukuro-cho in 1765 and to Asakusa Tenmondai (Asakusa Astronomical Observatory, also known as Hanrekisho) in 1782. At that time, the term 'Tenmondai' (astronomical observatory) was used for the first time. Yoshitoki TAKAHASHI and Shigetomi HAZAMA were engaged in Kansei calendar revision at Ushigome Fukuro-cho/Asakusa, and Tadataka INO studied astronomy and surveying from Yoshitoki TAKAHASHI at Asakusa Temnondai. In 1842, another tenmondai was established at Kudanzaka thanks to the efforts of Kagesuke SHIBUKAWA, etc. When Tenmonkata was abolished in 1869, tenmondai at Asakusa and Kudan were also abolished.

Abolition of Tenmonkata

After Taisei Hokan (restoration of Imperial rule) and the Battle of Toba and Fushimi, Haruo TSUCHIMIKADO asked the Imperial Court and took back the right of calendrical calculations and calendar distribution to the Tsuchimikado family. Tenmonkata was abolished and Haruo became the responsible person, in place of Yoshinori SHIBUKAWA and Akitsune YAMAJI who were then Tenmonkata, as Onmyo no kami (director of the bureau of divination). The Tsuchimikado family made a calendar of 1869, but Haruo died in 1869 and Kazumaru, who was then 11 years old, succeeded as the head of Tsuchimikado family. In 1870, the authority of astronomical calendar study was transferred to the Tenmon Rekido-kyoku (Astronomical Calendar Study Bureau) of Ministry of Education. In the same year, the Tenmon Rekido-kyoku was moved to Tokyo and was renamed Seigaku-kyoku. Magotaro (Yoshinori) SHIBUKAWA, a former Tenmonkata, was employed by Seigaku-kyoku. At the end of the year, Kazumaru (Harenaga) TSUCHIMIKADO was dismissed from the position of daigaku goyogakari (person in charge of the education of the Imperial Household) and the privileged status of Tsuchimikado family in calendar study was abolished.