Yasui Santetsu

安井 算哲 (1589/90–1652)

First head of the Yasui house.

He was the main rival to Nakamura Doseki the founder of the Inoue-house. According to traditional records, they are supposed to have played 120 games over a period of just a few years, with Doseki winning two thirds of them. They also played the very first castle game in 1626.

His two oldest sons, Santetsu II (Shibukawa Shunkai) and Chitetsu, were the leading disciples (together with Yasui Shunchi) of Yasui II Sanchi, but all of them were bested by Honinbo Dosaku.