Ajima Naonobu

In this Japanese name, the family name is "Ajima".

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

Ajima is credited with introducing calculus into Japanese mathematics. This significance of this innovaction is not diminished by a likelihood that he had access to European writings on the subject.^[2] Ajima also posed the question of inscribing three mutually tangent circles in a triangle;^[3] 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.^[4][5]

Ajima was an astronomer at the Shogun's Observatory (Bakufu Temmongaki).^[6]

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.^[7]

Selected works

In a statistical overview derived from writings by and about Ajima Naonobu, OCLC/WorldCat encompasses roughly 20+ works in 30+ publications in 2 languages and 40+ library holdings.^[8]

This is an incomplete list, which may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries.

• Ajima Naonobu zenshū (安島直円全集^?) "017232052" OCLC 017232052, collected works
• Sanpō kosō (算法考艸^?) OCLC 22057185881, algorithms considered
• Jujireki bimmo (Introduction of the 'Works and Days Calendar')^[6]
• Anshi seiyo-reki koso (Ajima's Studies for Western Calendars)^[6]
• Ajima sensei bimmo do jutsu (Methods of Professor Ajima's 'bimmo' )^[6]
• Koshoku mokyu zokkai (Introduction of Eclipses of the Sun and the Moon)^[9]
• Sansha San'en Jutsu (Methods of Three Diagonals and Three Circles)^[10]

See also

• Sangaku, the custom of presenting mathematical problems, carved in wood tablets, to the public in shinto shrines
• Soroban, a Japanese abacus
• Japanese mathematics (wasan)

Notes

1. ^ Smith, David. (1914). A History of Japanese Mathematics, pp. 195-205. at Google Books
2. ^ Restivo, Sal P. (1992). Mathematics in Society and History: Sociological Inquiries, p. 58. at Google Books
3. ^ Fukagawa, Hidetoshi; Rothman, Tony (2008), Sacred mathematics: Japanese temple geometry, Princeton University Press, p. 79, ISBN 9780691127453, http://books.google.com/books?id=OxKKDCmGDlEC&pg=PA79 .
4. ^ Weisstein, Eric W., "Ajima-Malfatti Points" from MathWorld..
5. ^ C. Kimberling, Encyclopedia of Triangle Centers, X(179) and X(180).
6. ^ ^{a b c d} Jochi, Shigeru. (1997). "Ajima Naonobu," Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures, p. 38. at Google Books
7. ^ United States Geological Survey: Planetary names, Naonobu; Naonobu lunar crater (in Japanese)
8. ^ WorldCat Identities: 安島直円 1739-1798
9. ^ Jochi, pp. 38-39. at Google Books
10. ^ Jochi, 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. 10-ISBN 0-684-10114-9
• Restivo, Sal P. (1992). Mathematics in Society and History: Sociological Inquiries. Dordrecht: Kluwer Academic Publishers. 10-ISBN 0-7923-1765-3/13-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. 10-ISBN 0-7923-4066-3/13-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

Persondata
Name	Ajima, Naonobu
Alternative names
Short description
Date of birth	1732
Place of birth
Date of death	1798
Place of death