He became the second generation Santetsu YASUI upon the death of his father in 1652, but wrote the name YASUI with the characters '保井' because the family's adopted son, Sanchi YASUI (written 安井), had become the head of the family.
1652年、父の死によって2世安井算哲となるが、安井家はすでに1世算哲の養子安井算知が継いでいたため保井姓を名乗った。