Hazama Shigetomi

A mid-Edo period astronomy and calendar scholar. The sixth son of a wealthy Osaka merchant. His childhood name was Magorokuro, his given name Shigetomi, his pen name Daigyo, his pen name Chogai, and his nickname Kounshujin. He inherited the family business at age 16 after his father's death due to the early deaths of his eldest brothers, and was commonly known as Juichiya Gorobei. He seems to have had an interest in astronomical instruments since his childhood, and is said to have astonished people by replicating a celestial sphere at age 12. In later years, he invented and improved many astronomical observation instruments, improving the accuracy of observations. He also trained craftsmen in his own home. At around the age of 30, he became a student of Asada Goryu, and studied calendar calculations with fellow student Takahashi Yoshitoki, but when Shigetomi's resourcefulness allowed him to obtain a copy of Rekisho Kosei Kohen, the three students became absorbed in studying it. In 1795 (Kansei 7), when the Shogunate was asked to discuss the reform of the calendar, Shigetomi participated in the reform, and two years later, he completed his important mission. Due to his contribution to the reform, he was allowed to use his family name and carry a sword, and after returning to Osaka, he was ordered to continue his observations at home as an astronomy officer. In 1803 (Kyowa 3), Shigetomi was ordered by the Shogunate to decipher the Dutch translation of the Lalande Tenmon-kata, but he passed away before he could complete the work. After that, Shigetomi left Edo again in 1804 (Bunka 1) to help Shigetomi's heir, Kageyasu, continue Shigetomi's work, and he remained in Edo until he returned to Osaka in 1809. After returning to Osaka, he went to Nara and Kyoto to investigate ancient measurements. Shigetomi had intended to have Shigetomi share half of the work of creating a map of Japan through a nationwide survey, but Shigetomi fell ill and postponed the survey, and Shigetomi passed away, missing the opportunity. Shigetomi was a representative Osaka townsman living around 1800, blessed with talent and wealth, but he was often ill and passed away in Bunka 13 at the age of 61. He is buried at Chausuyama Houfukuji Temple in Tennoji Ward, Osaka City.

Shigetomi's eldest son, Juushin (1786-1838), was also an accomplished astronomical observer, and together with his father and following in his footsteps, he continued to make astronomical observations, leaving behind many records.

[Toshio Watanabe]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

江戸中期の天文暦学者。大坂の豪商の六男。幼名孫六郎、諱(いみな)は重富、字(あざな)は大業、号は長涯(ちょうがい)、耕雲主人(こううんしゅじん)ともいう。長兄たちの夭死(ようし)により、父の没後16歳で家督を相続、通称を十一屋五郎兵衛という。少年時代から天文儀器に関心があったようで、12歳で渾天儀(こんてんぎ)を模造して人を驚かしたという。後年多くの天文観測器を創案改良し、観測の精度を高めた。自家で工人をも養成した。30歳ごろ麻田剛立(ごうりゅう)に入門し、同門の高橋至時(よしとき)と暦算の研究に励んだが、重富の機知をもって『暦象考成後編』を入手すると、師弟3人はこれの研究に没頭した。1795年（寛政7）幕府に改暦の議がおこると徴されて改暦に参画し、2年後大任を果たした。改暦の功により名字帯刀を許され、帰坂後も天文方の待遇で自宅で観測を命ぜられた。1803年（享和3）至時が幕命により『ラランデ天文書』のオランダ語訳書を解読したが、業なかばで他界、その後、重富は至時の嗣子(しし)景保(かげやす)を助けて至時の遺業を続行するため1804年（文化1）再度出府、1809年帰坂するまで江戸にとどまった。帰坂後は奈良、京都に古尺取調べに回った。至時は、全国測量による日本地図の作製の一半を重富にも分担させるつもりであったが、重富が病にかかり測量を延ばしている間に、至時は死去し、その機を失った。重富は恵まれた才能と財力によって1800年前後に生きた大坂町人を代表する人物であったが、病気がちで文化(ぶんか)13年、61歳で没した。大阪市天王寺区茶臼山(ちゃうすやま)邦福(ほうふく)寺に葬る。

　重富の長子重新(じゅうしん)（1786―1838）も優れた天文観測者であり、父とともに、またその後を継いで天文観測を続行し多くの記録を残した。

［渡辺敏夫］

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