While a portrait of a lovely courtesan may seem to be an unlikely subject for a Zen painting, there are actually a number of works like this. Most of the inscriptions say, in essence, "Watch out!" but Zen masters know that most men will ignore that advice and in fact need to have the experience of loving a women. That is the only way one learns about the "Form" aspect of the "Form is Emptiness, Emptiness is Form" equation. Also, such great masters as Ikkyu, Hakuin, and Sengai had courtesan disciples and they did not treat them differently from their other students. They were just doing their (important) job. No information on the painter Nanpo.
Shogetsu was the pen name of the Chuho So-u, 406th abbot of Daitoku-ji. Shogetsu was a tea master as well as a Zen master, and he was one of the major cultural figures in Kyoto during his lifetime. Shogetsu was an excellent and productive Zen artist. Shogetsu is especially known for his calligraphy and enso paintings; he often joint pieces with other artists as well.