Takebe Kenko

In this Japanese name, the family name is Takebe.

Takebe Katahiro (建部 賢弘, 1664 – August 24, 1739), also known as Takebe Kenkō, was a Japanese mathematician in the Edo period.[1]


Takebe was the favorite student of Seki Takakazu[1] Takebe is considered to have extended and disseminated Seki's work.[2]

In 1706, Takebe was offered a position in the Tokugawa shogunate's department of ceremonies.[1]

In 1719, Takebe's new map of Japan was completed; and the work was highly valued for its quality and detail.[1]

Shogun Yoshimune honored Takebe with rank and successively better positions in the shogunate.[3]


Takebe played critical role in the development of the Enri (円理, "circle principle") - a crude analogon to the western calculus. He also created charts for trigonometric functions.[4]

He obtained power series expansion of in 1722, 15 years earlier than Euler. This was the first power series expansion obtained in Wasan. This result was first conjectured by heavy numeric computation.

He used Richardson extrapolation, about 200 years earlier than Richardson.

He also computated 41 digits of , based on polygon approximation and Richardson extrapolation.

Takebe Prizes

In the context of its 50th anniversary celebrations, the Mathematical Society of Japan established the Takebe Prize and the Takebe Prizes for the encouragement of young people who show promise as mathematicians.[4]

Selected works

In a statistical overview derived from writings by and about Takebe Kenko, OCLC/WorldCat encompasses roughly 10+ works in 1o+ publications in 3 languages and 10+ library holdings.[5]

This is a dynamic list and may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries.

See also



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