Oshima Zenzaemon

...A mathematician in the mid-Edo period. Commonly known as Zenzaemon, he also wrote the pen name Shibaran. He was a kimono shop owner in Osaka, but went bankrupt. He first studied mathematics under Maeda Kenshu, and later under Shimada Naomasa and Nakane Motokei. He learned surveying from Murakami Sasuke Yoshiyori, father of Kurushima Yoshita, as well as Kita Shinshichi Haruhaku and Furuichi Sansuke Masanobu. He was also knowledgeable in astronomy and calendar science. He traveled around Osaka, Kansai, and Shikoku, and trained many disciples. His contribution to spreading mathematics throughout the country is great. Oshima's algebraic symbols are slightly different from those of Seki Takakazu. He improved Seki Takakazu's zero reduction technique (approximate fractions) and left behind many mathematics books. ...

*Some of the terminology that refers to "Oshima Zenzaemon" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…江戸中期の数学者。通称善左衛門。芝蘭と号した。大坂の呉服屋であったが破産。初め前田憲舒に数学を習い，後に島田尚政に，さらに中根元圭に指導を受ける。測量術を久留島義太の父村上佐助義寄に，また喜多新七治伯や古市算助正信にも学ぶ。天文，暦学にも通じていた。大坂を中心にして，関西，四国を遊歴し，多くの弟子を養成した。数学を各地に普及させた功績は大である。大島の代数記号は，関孝和と少し違うところがある。彼は関孝和の零約術(近似分数)を改良し，多くの数学書を残した。…

※「大島善左衛門」について言及している用語解説の一部を掲載しています。

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