Kikuchi Dairoku

Mathematician. Born as the second son of the Western scholar Mitsukuri Shuhei at the Tsuyama Domain residence in Edo, he inherited his father's family, the Kikuchi family. He entered the Bansho Shirabesho (Institute for the Investigation of Foreign Documents) at the age of six, and became a Tobunnosuke (temporary assistant) professor of punctuation at the age of nine. At the age of eleven, he studied in England at the order of the shogunate, but returned to Japan due to the collapse of the shogunate. In 1870 (Meiji 3), he studied in England again at the order of the Meiji government, and returned to Japan after graduating from Cambridge University in 1877. In June of the same year, when the University of Tokyo was founded, he became the only Japanese professor at the Faculty of Science of the University of Tokyo. For the next twenty years, he taught mathematics and contributed to the advancement of mathematics by writing many books and enlightening treatises, and he trained world-famous mathematicians who would lead the next generation of Japanese mathematics, such as Fujisawa Rikitaro and Takagi Teiji. He served as president of Tokyo Imperial University in 1898, Minister of Education in 1901 (Meiji 34), president of Kyoto Imperial University in 1908, and president of the Imperial Academy in 1909. He also served as the first director of the RIKEN Institute when it was established in 1917 (Taisho 6), making great contributions to the improvement of education and culture in Japan.

His main works include "Mathematical Commentary" (1886, Hakubunsha), a translation of a book by Clifford William K. (1845-1879) and Pearson, and "Textbook of Elementary Geometry" volumes 1 and 2 (1888 and 1889, Henshukyokyoku, Ministry of Education). The former is an important enlightening book, containing the contents of a British-style introduction to mathematics. The latter is a book on Euclidean geometry, which also describes the theory of proportions. It contained theoretical content that was world-class at the time, and was of great significance in informing the academic world of how deep consideration was required to properly understand mathematics. This book was also the first officially published book to be written horizontally, and was famous for being written with divided words. In 1912, he wrote " Analytic Geometry ", a textbook on analytical geometry for high schools, which was widely used.

[Junro Komatsu]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

数学者。洋学者箕作秋坪(みつくりしゅうへい)の次男として、江戸の津山藩邸で生まれ、父の実家菊池家を継いだ。6歳で蕃書調所(ばんしょしらべしょ)に入り、9歳で句読(くとう)教授当分助(とうぶんのすけ)となる。11歳のとき幕命でイギリスに留学したが、幕府瓦解(がかい)のため帰国。1870年（明治3）明治政府の命で再度イギリスに留学し、1877年ケンブリッジ大学を卒業して帰国した。同年6月、東京大学創設に際し、日本人としてただ一人の東京大学理学部教授となり、以降20年間、数学を教授するとともに、多くの著書、啓蒙(けいもう)論文を著して数学の進歩に尽くし、藤沢利喜太郎(ふじさわりきたろう)、高木貞治(たかぎていじ)ら、次代の日本の数学を担った世界的にも著名な数学者を育てた。1898年東京帝国大学総長、1901年（明治34）文部大臣、1908年京都帝国大学総長、1909年帝国学士院院長などを歴任し、1917年（大正6）理化学研究所の設立とともに初代所長となるなど、日本の教育・文化の向上に大きな功績を残した。

　おもな著作には、クリッフォードWilliam K. Clifford（1845―1879）とピアソン著の本の翻訳書『数理釈義』（1886・博聞社刊）と、菊池著の『初等幾何学教科書』巻1、2（1888、1889・文部省編輯局(へんしゅうきょく)刊）がある。前者はイギリス流の数学序説の内容で啓蒙書として重要である。また後者はユークリッド幾何の本で、比例理論まで述べたものであるが、当時世界的にも有数な理論的内容をもち、数学を正しく理解するためにはいかに深い考察を要するかを学界に知らせた意義は大きい。また、この本は官版の本としては初めての横書きで、分かち書きの本として有名であった。1912年には高校の解析幾何の教科書『Analytic Geometry』を著し、多く使われた。

［小松醇郎］

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