Ajima Naonobu

Template:Family name hatnote Template:Nihongo, also known as Ajima Manzō Chokuyen, was a Japanese mathematician of the Edo period.<ref name="smith1914">Smith, David. (1914). Template:Google books</ref>

His Dharma name was (祖眞院智算量空居士).<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

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.<ref>Restivo, Sal P. (1992). Template:Google books</ref> Ajima also posed the question of inscribing three mutually tangent circles in a triangle;<ref>Template:Citation.</ref> 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.<ref>Template:Mathworld.</ref><ref>C. Kimberling, Encyclopedia of Triangle Centers Template:Webarchive, X(179) and X(180).</ref>

Ajima was an astronomer at the Shogun's Observatory (Bakufu Temmongaki).<ref name="jochi38">Jochi, Shigeru. (1997). Template:Google books</ref>

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.<ref>United States Geological Survey: Naonobu Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

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.<ref>WorldCat Identities Template:Webarchive: 安島直円 1739-1798</ref> {{#invoke:Hatnote|hatnote}}{{#ifeq:||}}

• Template:Nihongo OCLC 017232052, collected works
• Template:Nihongo OCLC 057185881, algorithms considered
• Template:Transliteration (Introduction of the 'Works and Days Calendar')<ref name="jochi38"/>
• Template:Transliteration (Ajima's Studies for Western Calendars)<ref name="jochi38"/>
• Template:Transliteration (Methods of Professor Ajima's 'Template:Transliteration')<ref name="jochi38"/>
• Template:Transliteration (Introduction of Eclipses of the Sun and the Moon)<ref>Jochi, Template:Google books</ref>
• Template:Transliteration (Methods of Three Diagonals and Three Circles)<ref>Jochi, Template:Google books</ref>
• Template:Transliteration (Periods of Decimal Fractions)<ref name="smith1914"/>

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

References

• Endō Toshisada (1896). Template:Nihongo. Tōkyō: _____. OCLC 122770600
• Oya, Shin'ichi. (1970). "Ajima Naonobu" in Dictionary of Scientific Biography, Vol. 1. New York: Charles Scribner's Sons. Template:ISBN
• Restivo, Sal P. (1992). Mathematics in Society and History: Sociological Inquiries. Dordrecht: Kluwer Academic Publishers. Template:ISBN; OCLC 25709270
• Selin, Helaine. (1997). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Dordrecht: Kluwer/Springer. Template:ISBN; 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