20 Facts About Seki Takakazu

Seki Takakazu, known as Seki Kowa, was a mathematician, samurai, and Kofu feudal officer of the early Edo period of Japan.

Seki Takakazu created a new algebraic notation system and, motivated by astronomical computations, did work on infinitesimal calculus and Diophantine equations.

Seki Takakazu calculated the value of pi correct to the 10th decimal place, having used what is called the Aitken's delta-squared process, rediscovered later by Alexander Aitken.

Seki Takakazu was influenced by Japanese mathematics books such as the Jinkoki.

Seki Takakazu's birthplace has been indicated as either Fujioka in Gunma Prefecture, or Edo.

Takakazu Seki was the second son of Uchiyama Shichibei Eimei, a samurai who served Tokugawa Tadanaga, his mother the daughter of Yuasa Yoemon, a servant of Ando Tsushima Mamoru.

Seki Takakazu was born to the Uchiyama clan, a subject of Ko-shu han, and adopted into the Seki Takakazu family, a subject of the shogun.

Seki Takakazu spent many years in studying 13th-century Chinese calendars to replace the less accurate one used in Japan at that time.

Seki Takakazu's mathematics was based on mathematical knowledge accumulated from the 13th to 15th centuries.

Seki Takakazu's work is more or less based on and related to these known methods.

Seki Takakazu learned this technique, most likely, through his close examination of Chinese calendars.

Seki Takakazu successfully applied it to problems suggested by his contemporaries.

In 1674, Seki Takakazu published Hatsubi Sanpo, giving solutions to all the 15 problems.

Seki Takakazu introduced the use of kanji to represent unknowns and variables in equations.

In 1683, Seki Takakazu pushed ahead with elimination theory, based on resultants, in the Kaifukudai no Ho.

Seki Takakazu developed his mathematics in competition with mathematicians in Osaka and Kyoto, at the cultural center of Japan.

Seki Takakazu is sometimes credited with Horner's method, which is not historically correct.

Seki Takakazu suggested an improvement to Horner's method: to omit higher order terms after some iterations.

Seki Takakazu studied the properties of algebraic equations for assisting in numerical solution.

Seki Takakazu obtained some evaluations of the number of real roots of a polynomial equation.