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Japanese mathematics

Japanese mathematics is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Japanese mathematics rather than just read about it. In short: Japanese mathematics (和算, wasan) 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 mathematical theory from Western mathematics (洋算 yōsan).

Japanese mathematics — main illustration
Japanese mathematics — illustration

Key takeaways

  • Japanese mathematics belongs to mathematics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Japanese mathematics to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Japanese mathematics from memory before moving on to harder problems.

Reference excerpt

Japanese mathematics (和算, wasan) 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 mathematical theory from Western mathematics (洋算 yōsan). In the history of mathematics, the development of wasan falls outside the Western realm. At the beginning of the Meiji period (1868–1912), Japan and its people opened themselves to the West. Japanese scholars adopted Western mathematical technique, and this led to a decline of interest in the ideas used in wasan.

History

Pre-Edo period (552-1600) Records of mathematics in the early periods of Japanese history are nearly non-existent. Though it was at this time that a large influx of knowledge from China reached Japan, including that of reading and writing, few sources exist of usage of mathematics within Japan. However, it is suggested that this period saw the use of an exponential numbering system following the law of a m ∗ a n = a m + n {\displaystyle a^{m}*a^{n}=a^{m+n}} .

Edo period

The Japanese mathematical schema evolved during a period when Japan's people were isolated from European influences, but instead borrowed from ancient mathematical texts written in China, including those from the Yuan dynasty and earlier. The Japanese mathematicians Yoshida Shichibei Kōyū, Imamura Chishō, and Takahara Kisshu are among the earliest known Japanese mathematicians. They came to be known to their contemporaries as "the Three Arithmeticians". Yoshida was the author of the oldest extant Japanese mathematical text, the 1627 work called Jinkōki. The work dealt with the subject of soroban arithmetic, including square and cube root operations. Yoshida's book significantly inspired a new generation of mathematicians, and redefined the Japanese perception of educational enlightenment, which was defined in the Seventeen Article Constitution as "the product of earnest meditation". Seki Takakazu developed *enri* (円理, “circle principles”), a mathematical system that addressed problems involving areas, volumes, and infinite series, broadly comparable in some aims to the problems later addressed by calculus in Europe.However Seki's investigations did not proceed from the same foundations as those used by Newton and leibniz in Europe. Mathematicians like Takebe Katahiro played an important role in developing Enri ("circle principle"). He obtained power series expansion of ( arcsin ⁡ ( x ) ) 2 {\displaystyle (\arcsin(x))^{2}} in 1722, 15 years earlier than Euler. He used Richardson extrapolation in 1695, about 200 years earlier than Richardson. He also computed 41 digits of π, based on polygon approximation and Richardson extrapolation.

Select mathematicians

The following list encompasses mathematicians whose work was derived from wasan.

Yoshida Mitsuyoshi (1598–1672) Seki Takakazu (1642–1708) Takebe Kenkō (1664–1739) Matsunaga Ryohitsu (fl. 1718-1749) Kurushima Kinai (d. 1757) Arima Raido (1714–1783) Fujita Sadasuke (1734-1807) Ajima Naonobu (1739–1783) Aida Yasuaki (1747–1817) Sakabe Kōhan (1759–1824) Fujita Kagen (1765–1821) Hasegawa Ken (c. 1783-1838) Wada Nei (1787–1840) Shiraishi Chochu (1796–1862) Koide Shuke (1797–1865) Omura Isshu (1824–1871)

See also Japanese theorem for cyclic polygons Japanese theorem for cyclic quadrilaterals Hungarian mathematics Sangaku, the custom of presenting mathematical problems, carved in wood tablets, to the public in Shinto shrines Soroban, a Japanese abacus Category:Japanese mathematicians

Notes

References Campbell, Douglas M. and John C. Iggins. (1984). Mathematics: People, Problems, Results. Belmont, California: Warsworth International. ISBN 9780534032005; ISBN 9780534032012; ISBN 9780534028794; OCLC 300429874 Endō Toshisada (1896). History of mathematics in Japan (日本數學史, Dai Nihon sūgakush). Tōkyō: _____. OCLC 122770600 Fukagawa, Hidetoshi, and Dan Pedoe. (1989). Japanese temple geometry problems = Sangaku. Winnipeg: Charles Babbage. ISBN 9780919611214; OCLC 474564475 __________ and Dan Pedoe. (1991) How to resolve Japanese temple geometry problems? (日本の幾何ー何題解けますか?, Nihon no kika nan dai tokemasu ka) Tōkyō. ISBN 9784627015302; OCLC 47500620 __________ and Tony Rothman. (2008). Sacred Mathematics: Japanese Temple Geometry. Princeton: Princeton University Press. ISBN 069112745X; OCLC 181142099 Horiuchi, Annick. (1994). Les Mathematiques Japonaises a L'Epoque d'Edo (1600–1868): Une Etude des Travaux de Seki Takakazu (?-1708) et de Takebe Katahiro (1664–1739). Paris: Librairie Philosophique J. Vrin. ISBN 9782711612130; OCLC 318334322 __________. (1998). "Les mathématiques peuvent-elles n'être que pur divertissement? Une analyse des tablettes votives de mathématiques à l'époque d'Edo." Extrême-Orient, Extrême-Occident, volume 20, pp. 135–156. Kobayashi, Tatsuhiko. (2002) "What kind of mathematics and terminology was transmitted into 18th-century Japan from China?", Historia Scientiarum, Vol.12, No.1. Kobayashi, Tatsuhiko. Trigonometry and Its Acceptance in the 18th-19th Centuries Japan. Ogawa, Tsukane. "A Review of the History of Japanese Mathematics". Revue d'histoire des mathématiques 7, fascicule 1 (2001), 137-155. Restivo, Sal P. (1992). Mathematics in Society and History: Sociological Inquiries. Dordrecht: Kluwer Academic Publishers. ISBN 9780792317654; OCLC 25709270 Selin, Helaine. (1997). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Dordrecht: Kluwer/Springer. ISBN 9780792340669; OCLC 186451909 David Eugene Smith and Yoshio Mikami. (1914). A History of Japanese Mathematics. Chicago: Open Court Publishing. OCLC 1515528; see online, multi-formatted, full-text book at archive.org

… excerpt ends here. Continue reading the full article.

Illustrations

Japanese mathematics: Replica of Katsuyo Sampo by Seki Takakazu. Page written about Bernoulli number and Binomial coefficient.
Replica of Katsuyo Sampo by Seki Takakazu. Page written about Bernoulli number and Binomial coefficient.

Worked examples

Example 1 — a first encounter with Japanese mathematics

Start with the simplest possible case. Write down what Japanese mathematics claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Japanese mathematics before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Japanese mathematics ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Japanese mathematics

In research
Japanese mathematics appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Japanese mathematics in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Japanese mathematics is common in secondary-school and first-year university syllabi. It links to neighbouring topics Japanese mathematics, Science and technology in Japan, so understanding it makes those chapters shorter.
In everyday life
Look for Japanese mathematics outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Japanese mathematics in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Japanese mathematics means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Japanese mathematics out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Japanese mathematics in simple terms?

Japanese mathematics (和算, wasan) 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 mathematical theory from Western…

Why does Japanese mathematics matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Japanese mathematics?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Japanese mathematics.

Tags

  • Japanese mathematics
  • Science and technology in Japan

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