Shigekiyo Muramatsu

Japanese: 村松茂清 - むらまつ・しげきよ

Year of death: 1695 (Genroku 8)
Year of birth: Keicho 13 (1608)
A Japanese mathematician of the early Edo period. Commonly known as Kutayu. Born in Muramatsu Village, Naka County, Hitachi Province (Ibaraki Prefecture). A disciple of Hiraga Yasuhide of Mito, he served the Asano family of Ako in Harima Province (Hyogo Prefecture) (His adopted son Hidenao and his son Takanao later participated in the attack on the Kira family). He taught mathematics in Edo as he was stationed there. His students included Yabe Sadaharu, Higuchi Kanetsugu, Kataoka Toyotada, Yuasa Tokuyuki, and Nomura Masashige. His book Sanzō, published in 1663 (Kanbun 3), is a textbook that was developed and edited based on Chinese mathematical books and the Zhenghaloku. In this book, he calculated the perimeter of a regular 32768-polygon inscribed in a circle, and gave the value of pi as 3.1415926, accurate to seven decimal places. This was the first correct calculation of the value of pi in Japan. It is believed that the idea of piecewise quadrature was used to calculate the circumference and area of a circle, and the volume of a sphere.

(Kenichi Sato)

Source: Asahi Japanese Historical Biography: Asahi Shimbun Publications Inc. About Asahi Japanese Historical Biography

Japanese:

没年：元禄8(1695)
生年：慶長13(1608)
江戸前期の和算家。通称九太夫。常陸国(茨城県)那珂郡村松村の出身。水戸の平賀保秀の門人で,播磨国(兵庫県)赤穂の浅野家に仕えた(養子の秀直とその子高直はのち吉良家討ち入りに参加)。江戸詰のため江戸で数学の教育に当たった。弟子に矢部定玄,樋口兼次,片岡豊忠,湯浅得之,野村政茂がいる。寛文3(1663)年の著書『算俎』は中国の算書や『竪亥録』を基本にし,発展させて編集した教科書である。この書で,円に内接する正32768角形の周の長さを計算し,円周率を3.1415926と小数点以下7桁まで正しい値を示した。これは日本最初の円周率の正しい値の計算である。円の周や面積,球の体積を求める際に区分求積法の発想があったものと評価される。

(佐藤健一)

出典　朝日日本歴史人物事典：（株）朝日新聞出版朝日日本歴史人物事典について　情報

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