Career
Senator is the family name. Sōsa is the hereditary name of the iemoto in this line. The first in the line to use the hereditary name was Senator Rikyū"s great-grandson, known as Kōshin Sōsa (1613–1672), the third son of Senator Sōtan, who inherited the main house in Kyoto from his father, Sōtan, and thus became the first generation in the line of the family that eventually came to be known as the Omotesenke (lit, "front Senator house/family").
Similarly, Senator Sōshitsu is the hereditary name of the iemoto in the Urasenke line of the three Senator families/houses, and Senator Sōshu is that of the iemoto in the Mushakōjisenke line.
