“A striking and distinguishing design featuring shunga within shunga. This may have been a self-advertisement by the artist himself, promoting shunga as a source of sexual knowledge to individuals and couples, and its ability to arouse desire.”
Reference: p.223 (Fig.10) in ‘Japonese Erotic Art, the Hidden World of Shunga’ by Ofer Shagan
Antique Japanese color woodblock. Shunga (Erotic print).