Raku IX Ryonyu (1756-1834)
楽九代 了入

Raku Ryonyu was the most prolific and longest-lived member of the Raku house. Ryonyu had responsibility thrust upon him at the young age of fourteen, when his sickly older brother Tokunyu (1745-1774) retired at the age of twenty-five and died four years later. Ryonyu occupied the position of Kichizaemon from 1770 to 1825, when he retired and received the name of Ryonyu from the head of the Omotesenke school of tea, Ryoryosai (1775-1825). Ryonyu continued to produce ceramics, both with his son and successor, in Kyoto, and at his retirement residence in Ishiyama in Omi Province.

References:
Pitelka, Morgan: Handmade Culture; Raku Potters, Patrons, and Tea Practitioners in Japan, Honolulu 2005, p.141.
Signature and seal of Ryonyu, see: Encyclopaedia of Signatures and Seals (落款花押大辞典 Rakkan Kao Daijiten), Kyoto 1982, p.1436.