Though there has been much scholarly research of the ukiyo-e, woodblock prints from premodern Japan, one sizable genre within this field has been notoriously neglected. This is the "shunga," the so-called spring pictures that were always erotic and, as this seminal study proves, often pornographic as well.
These prints were intended to arouse, and the author's reasons for believing this are irrefutable. Among them is that their major appearance coincides with the massive urbanization of Japan beginning in the 17th century.
The cities were demographically artificial, none more so than Edo. It was two-thirds male, and Saikaku called it a "city of bachelors": a million people, few of whom had been born there. At the same time the city was severely disciplined and not many could afford what pleasure quarters there were.