Kogetsu Sogan (1574-1643) was the son of famous tea master, Tsuda Sogyu, and became the abbot of Daitokuji Temple, Kyoto. He had a very close relationship with Shokado and Kobori Enshu (1579-1647) through Kyoto tea circles in the late Momoyama and early Edo period. His poem describes this scene of making ink.
The Tang-dynasty eccentric monks, Kanzan and Jittoku, have been a popular subject in Japanese painting since the Muromachi period. For similar examples of Jittoku grinding ink on a stone and Kanzan writing a poem on a rock, see Tochigi Prefectural Museum of Art, ed., Kanzan Jittoku: Egakareta fukyo no soshi tachi (Kanzan and Jittoku: Paintings of eccentric monks) (Tochigi: Tochigi Prefectural Museum of Art, 1994), pls. 24, 26, 73 and 84.