Keicho 18 (1613) - Kanbun 12 (1672). The fourth Iemoto of Omotesenke. He was the third son of Genpaku Sotan and went to work as tea master for the Tokugawa family of Kii Province. He became head of the Sen family, inherited the Fushin'an tea room and strengthened the foundations of Omotesenke. From the time of Koshin, Omotesenke's Iemotos were called 'Sosa'.