With the assistance of Satsuma clan, Ryoma together with his peers who also fled from Tosa clan established shachu (Kameyama-shachu, later Kaientai (ronin's association)) in Nagasaki and carried on trade of goods and arms.
薩摩藩の援助により、土佐脱藩の仲間と共に長崎で社中（亀山社中・のちに海援隊_(浪士結社)）を組織し、物産・武器の貿易を行った。