, also known as Ajima Manzō Chokuyen, was a Japanese
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...
of the
Edo period
The , also known as the , is the period between 1600 or 1603 and 1868 in the history of Japan, when the country was under the rule of the Tokugawa shogunate and some 300 regional ''daimyo'', or feudal lords. Emerging from the chaos of the Sengok ...
.
[Smith, David. (1914). ]
His
Dharma name
A Dharma name is a new name acquired during both lay and monastic Buddhist initiation rituals in Mahayana Buddhism and Pabbajjā, monastic ordination in Theravada Buddhism (where it is more proper to call it Dhamma or Sangha name). The name is ...
was (祖眞院智算量空居士).
Work
Ajima is credited with introducing
calculus
Calculus is the mathematics, mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizations of arithmetic operations.
Originally called infinitesimal calculus or "the ...
into Japanese mathematics. The significance of this innovation is diminished by a likelihood that he had access to European writings on the subject. Ajima also posed the question of inscribing three mutually tangent circles in a triangle; these circles are now known as
Malfatti circles after the later work of
Gian Francesco Malfatti
Giovanni Francesco Giuseppe Malfatti, also known as Gian Francesco or Gianfrancesco (26 September 1731 – 9 October 1807) was an Italian mathematician. He was born in Ala, Trentino, Holy Roman Empire and died in Ferrara.
Malfatti studied at the ...
, but two
triangle center
In geometry, a triangle center or triangle centre is a point in the triangle's plane that is in some sense in the middle of the triangle. For example, the centroid, circumcenter, incenter and orthocenter were familiar to the ancient Greeks, ...
s derived from them, the Ajima–Malfatti points, are named after Ajima.
Ajima was an astronomer at the Shogun's Observatory (''Bakufu Temmongaki'').
[Jochi, Shigeru. (1997). ]
Legacy
In 1976, the
International Astronomical Union
The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
(IAU) honored Ajima by identifying a crater on the
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
with his name.
Naonobu is a small
lunar impact crater
An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...
located on the eastern
Mare Fecunditatis
Mare Fecunditatis (Latin ''fēcunditātis'', the "Sea of Fecundity" or "Sea of Fertility") is a lunar mare in the eastern half of the visible Moon. The mare has a maximum diameter of 840 km.
__NOTOC__ Description
The Fecunditatis basin forme ...
, to the northwest of the prominent crater
Langrenus.
Selected works
In a statistical overview derived from writings by and about Ajima Naonobu,
OCLC
OCLC, Inc. See also: is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It was founded in 1967 as the ...
/
WorldCat
WorldCat is a union catalog that itemizes the collections of tens of thousands of institutions (mostly libraries), in many countries, that are current or past members of the OCLC global cooperative. It is operated by OCLC, Inc. Many of the O ...
encompasses roughly 20+ works in 30+ publications in two languages and 40+ library holdings.
*
OCLC 017232052 collected works
*
OCLC 057185881 algorithms considered
* (''Introduction of the 'Works and Days Calendar)
* (''Ajima's Studies for Western Calendars'')
* (''Methods of Professor Ajima's'' '')
* (''Introduction of Eclipses of the Sun and the Moon'')
* (''Methods of Three Diagonals and Three Circles'')
[Jochi, ]
* (''Periods of Decimal Fractions'')
See also
*
Sangaku
Sangaku or san gaku () are Japanese Euclidean geometry, geometrical problems or theorems on wooden tablets which were placed as offerings at Shinto shrines or Buddhist temples in Japan, Buddhist temples during the Edo period by members of all so ...
, the custom of presenting mathematical problems, carved in wood tablets, to the public in
shinto shrines
A Stuart D. B. Picken, 1994. p. xxiii is a structure whose main purpose is to house ("enshrine") one or more kami, , the deities of the Shinto religion.
The Also called the . is where a shrine's patron is or are enshrined.Iwanami Japanese dic ...
*
Soroban
The is an abacus developed in Japan. It is derived from the History of Science and Technology in China, ancient Chinese suanpan, imported to Japan in the 14th century. Like the suanpan, the soroban is still used today, despite the proliferation ...
, a Japanese
abacus
An abacus ( abaci or abacuses), also called a counting frame, is a hand-operated calculating tool which was used from ancient times in the ancient Near East, Europe, China, and Russia, until the adoption of the Hindu–Arabic numeral system. A ...
*
Japanese mathematics
denotes a distinct kind of mathematics which was developed in Japan during the Edo period (1603–1867). The term ''wasan'', from ''wa'' ("Japanese") and ''san'' ("calculation"), was coined in the 1870s and employed to distinguish native Japanese ...
Notes
References
* Endō Toshisada (1896). . Tōkyō: _____
OCLC 122770600* Oya, Shin'ichi. (1970). "Ajima Naonobu" in ''
Dictionary of Scientific Biography
The ''Dictionary of Scientific Biography'' is a scholarly reference work that was published from 1970 through 1980 by publisher Charles Scribner's Sons, with main editor the science historian Charles Coulston Gillispie, Charles Gillispie, from Pri ...
,'' Vol. 1. New York: Charles Scribner's Sons.
* Restivo, Sal P. (1992)
''Mathematics in Society and History: Sociological Inquiries.''Dordrecht: Kluwer Academic Publishers.
OCLC 25709270*
Selin, Helaine. (1997)
''Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures.''Dordrecht:
Kluwer
Wolters Kluwer N.V. is a Dutch information services company. The company serves legal, business, tax, accounting, finance, audit, risk, compliance, and healthcare markets.
Wolters Kluwer in its current form was founded in 1987 with a merger bet ...
/
Springer
Springer or springers may refer to:
Publishers
* Springer Science+Business Media, aka Springer International Publishing, a worldwide publishing group founded in 1842 in Germany formerly known as Springer-Verlag.
** Springer Nature, a multinationa ...
.
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
{{DEFAULTSORT:Ajima, Naonobu
1732 births
1798 deaths
18th-century Japanese mathematicians
Writers of the Edo period
Japanese Buddhists