Ajima Naonobu

Japanese mathematician (1732–1798)

Ajima Naonobu
Born	1732
Died	May 20, 1798
Nationality	Japanese
Occupation	mathematician
Known for	Credited with introducing calculus into Japanese mathematics

Ajima Naonobu (安島直円, 1732 – May 20, 1798), also known as Ajima Manzō Chokuyen, was a Japanese mathematician of the Edo period.^[1]

His Dharma name was (祖眞院智算量空居士).^[2]

Work

Ajima is credited with introducing calculus into Japanese mathematics. The significance of this innovation is diminished by a likelihood that he had access to European writings on the subject.^[3] Ajima also posed the question of inscribing three mutually tangent circles in a triangle;^[4] these circles are now known as Malfatti circles after the later work of Gian Francesco Malfatti, but two triangle centers derived from them, the Ajima–Malfatti points, are named after Ajima.^[5]^[6]

Ajima was an astronomer at the Shogun's Observatory (Bakufu Temmongaki).^[7]

Legacy

In 1976, the International Astronomical Union (IAU) honored Ajima by identifying a crater on the Moon with his name. Naonobu is a small lunar impact crater located on the eastern Mare Fecunditatis, to the northwest of the prominent crater Langrenus.^[8]^[9]

Selected works

In a statistical overview derived from writings by and about Ajima Naonobu, OCLC/WorldCat encompasses roughly 20+ works in 30+ publications in two languages and 40+ library holdings.^[10]

Ajima Naonobu zenshū (安島直円全集) OCLC 017232052, collected works
Sanpō kosō (算法考艸) OCLC 057185881, algorithms considered
Jujireki bimmo (Introduction of the 'Works and Days Calendar')^[7]
Anshi seiyo-reki koso (Ajima's Studies for Western Calendars)^[7]
Ajima sensei bimmo do jutsu (Methods of Professor Ajima's 'bimmo')^[7]
Koshoku mokyu zokkai (Introduction of Eclipses of the Sun and the Moon)^[11]
Sansha San'en Jutsu (Methods of Three Diagonals and Three Circles)^[12]
Fujin Isshũ (Periods of Decimal Fractions)^[1]

Notes

^ ^a ^b Smith, David. (1914). A History of Japanese Mathematics, pp. 195-205., p. 195, at Google Books
^ "名墓録". 矢島俯仰 (in Japanese). Retrieved 2019-10-18.
^ Restivo, Sal P. (1992). Mathematics in Society and History: Sociological Inquiries, p. 58. , p. 58, at Google Books
^ Fukagawa, Hidetoshi; Rothman, Tony (2008), Sacred mathematics: Japanese temple geometry, Princeton University Press, p. 79, ISBN 978-0-691-12745-3.
^ Weisstein, Eric W. "Ajima-Malfatti Points". MathWorld..
^ C. Kimberling, Encyclopedia of Triangle Centers Archived 2012-04-19 at the Wayback Machine, X(179) and X(180).
^ ^a ^b ^c ^d Jochi, Shigeru. (1997). "Ajima Naonobu," Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures, p. 38., p. 38, at Google Books
^ United States Geological Survey: Naonobu Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
^ "Naonobu lunar crater (in Japanese)". Archived from the original on 2007-12-21. Retrieved 2004-07-19.
^ WorldCat Identities Archived 2010-12-30 at the Wayback Machine: 安島直円 1739-1798
^ Jochi, pp. 38-39., p. 38, at Google Books
^ Jochi, p. 39., p. 39, at Google Books

References

Endō Toshisada (1896). History of mathematics in Japan (日本數學史史, Dai Nihon sūgakush). Tōkyō: _____. OCLC 122770600
Oya, Shin'ichi. (1970). "Ajima Naonobu" in Dictionary of Scientific Biography, Vol. 1. New York: Charles Scribner's Sons. ISBN 0-684-10114-9
Restivo, Sal P. (1992). Mathematics in Society and History: Sociological Inquiries. Dordrecht: Kluwer Academic Publishers. ISBN 978-0-7923-1765-4; OCLC 25709270
Selin, Helaine. (1997). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Dordrecht: Kluwer/Springer. ISBN 978-0-7923-4066-9; OCLC 186451909
David Eugene Smith and Yoshio Mikami. (1914). A History of Japanese Mathematics. Chicago: Open Court Publishing. OCLC 1515528 -- note alternate online, full-text copy at archive.org