UC Santa Cruz

Japan in the Edo period (1603 - 1867) closed virtually all direct contacts with the Western countries and subsequently developed a unique style of mathematics independently of the West. We present a historical account of various mathematical problems described in ”sangaku” (mathematical tablets displayed in shrines and temples in Japan) that were hung by many mathematics aficionados from different socioeconomic classes. These tablets contain interesting mathematical problems and answers, and the contributors considered the tablets sacred because they spent years to solve their problems. Sometimes, interesting mathematical problems and theorems were discovered many years before the Western counter parts. We describe some of the problems and prove them, using a modern mathematical notation. We also mention the history of mathematics related to sangaku problems and discuss the mechanisms of mathematical education and communication in Japan at that time period.