7th generation Chikusō Sōshitsu (1709-33) 竺叟 宗室
Second son of Omotesenke’s Iemoto, Gensô, was adopted by Rikkansai that probably intended for him to marry Rikkansai’s younger sister. However Rikkansai died before this could happen. Chikusō was eight at that time. Gensô Sôsa looked after the new head of the Urasenke family for the comming four years before passing away himself. Saisaisai died at the age of 25 still unmarried.