関孝和墓（浄輪寺）

所在地　新宿区弁天町95　（浄輪寺）

東京都指定史跡
　関孝和墓せきたかかず
　　　　　昭和33年（1958）10月7日指定

　和算を大成した関孝和は、駿河大納言徳川忠長に仕えた内山七兵衛永明の次男として生れました。出生地や生年は未詳ですが、その後甲府藩士の関五郎左衛門の養子となり、藩主綱豊が6代将軍家宣となったのちは、幕臣として納戸組頭を勤めました。
　孝和は従来の算木を用いた「天元術」を改良して「点竄術」と呼ばれる筆算式代数学を創案し、和算が高等数学として確立する礎を築きました。著述には『発微算法』等があり宝永5年（1708）に没した後は、門人により『括要算法』や「大成算経」等が著され、世に「算聖」と称されました。
　現存する2代目の墓石は舟形、高さ158センチ、鳳凰丸紋に「法行院殿宗達日心大居士、宝永五戌子年十月二十四日卒」、左側に「姓藤原、諱孝和、称関新助」とあります。
　平成20年（2008）3月設置　東京都教育委員会　

        Seki Takakaza Haka
 Seki Takakazu was a mathematician from the Early and Middle Edo Period,whoelaborated the Japanese mathematics.He was born as a second son to Uxhiyama Shichibe nagaakira who served for Tokugawa Tadanaga also known asa Suruga Ddainagon.The date of birth and brithplace of the great mathematician is unknown.He was then adopted by Seki Gorozaemon who served for a lord of Kofu domain at thet time,and after lord of Kofu domain Tsunatoyo was appointed as the sixth shogun and renamed Ienobu,he served as a Head of Accounting Department in the shogunate administrative system.
 Takakazu deeply studiedtianyuan shu or procedure of the celestial elemant,which were remarkably developed under the Song-Chin-Yuan dynasties;he also radically improved th procedure.He further foundations for the Japanese mathematics' way to advancedmath.His works include Mathematical Methods for Finding Details (1674);further after his death in 1708,his writings Compendium of Mathematics and Comprehensive Classic of Mathematics were published by his disciples,and the great mathematician was called a saint of mathematics.The extant second tombstone is shaped in a shape of ship and 158 cm tall,with a crest of Phenix openingwings in a circulara shepe,accompanied by an inscription stating Hogyo-inden Sodatsu Nisshin Daikoji died on October 24,1708,the Year of Boshi,as well as  aleft-side inscription He was of Fujiwara clan,and given an abtual name Takakazu,also known as Seki Shinsuke.
 Tokyo Metropolitan Board of Education