Authentic Edo period original, c.1800, Japanese erotic art shunga woodblock print picture by a member of the Kitagawa School. 
 
Shunga picture measures approximately 10.3 cm x 16 cm.  Very good colors and impressions.  Condition is good for its age with some wear, soiling, and wormage mainly on the white border to the right of the artwork.  No backing.  Please see and judge from photos provided.
 
Japanese original shunga woodblock print picture presenting two highly unusual, side-by-side studies of the “ideal” erect male phallus.  Rather than depicting a conventional erotic encounter, the artist isolates and compares the male genitalia, complete with written annotations and measurements, giving the composition the remarkable appearance of an Edo-period erotic anatomical guide.
 
This exceptionally unusual treatment is also significant within the history of shunga.  Such highly enlarged and anatomically focused imagery by the Kitagawa School directly influenced Keisai Eisen, who later copied this distinctive approach into his own celebrated anatomical erotic works of the early-to-mid 19th century.  A fascinating and rare example of the more instructional and distinctly homoerotic side of Edo-period shunga!