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NEW: SANGAKU REFLECTIONS: A Japanese Mathematician Teaches

189 Sangaku Reflections
J. Marshall Unger
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About the Author

J. Marshall Unger is Emeritus Professor of Japanese at Ohio State University. His research has focused on the history of Japanese, teaching Japanese as a second language, and writing systems of East Asia. Two of his books, The Fifth Generation Fallacy and Literacy and Script Reform in Occupation Japan, are available in Japanese.

About the Book

During the period of national isolation, a mathematical tradition called wasan flourished in Japan. Though virtually unknown to Europeans before the Meiji Restoration, its practitioners, the wasanka, produced some results comparable to (and sometimes in advance of) those of mathematicians of the European Enlightment.  This volume, a companion to Unger’s earlier translation of solutions by Aida Yasuaki (1747–1817), focuses on problems that Aida most likely used as a teacher. Unger explains the reasons for believing this, and sheds further light on the intellectual milieu in which Aida worked by discussing other books by Aida, including one in which he describes Dutch techniques of navigation.  A specialist in the history of the Japanese language, Unger aims to make actual wasan materials accessible to bring fellow amateur mathematicians and interested professionals, and to explore new aspects of how wasan fit into the larger picture of premodern Japanese cultural history.


See also Sangaku Proofs: A Japanese Mathematician at Work (2015)

978-1-939161-55-0 hc $25

This interpretive translation of a suite of twenty-six related problems analyzed by Aida Yasuaki (1847–1817) gives readers unfamiliar with the premodern Japanese language access to a real wasan text. Instead of presenting and solving problems using modern techniques, Unger presents Aida’s own solutions, transcribing his calculations into familiar mathematical notation, highlighting connections between Aida’s work and both the mathematics of today and aspects of Japanese cultural history. A specialist in the history of the Japanese language, he aims to bring fellow amateur mathematicians and interested professionals into contact with actual wasan methods, and to initiate a discussion of how wasan fits into the larger picture of premodern Japanese history.


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