Authentic Edo period original, c.1836, Japanese erotic art shunga woodblock print picture by Kunisada Utagawa (1786-1865).  From the shunga series, Shunjo gidan mizuage-cho (Erotic Tales of Prostitutes and Deflowering).
 
Shunga picture measures 19.7 cm x 26.8 cm.  Excellent colors - especially in the rich deep blues of the water - and impressions!  Condition is good with a bit of wear and cropped borders.  Album backing on reverse.  Please see and judge from photos.
 
This composition cleverly frames the couple’s intimacy within the circular vignette of a telescope view, revealing that their act aboard the boat is being secretly observed from a distance.  The voyeuristic element adds both humor and tension, turning the shunga scene into a layered narrative rather than a purely private encounter.  Kunisada’s use of deep indigo blues in the water and garments, along with the dynamic placement of figures, underscores the sophistication of the woodblock print and the playful, theatrical quality typical of Edo-period shunga.