"It is just like consciousness and unconsciousness, intelligence and desire...By depicting both sides of the coin, giving the same weight to the front and the back, the artists are saying 'people have both. That's what makes us human. Be sure you look at both sides equally.'"[1]
 

- Monta Hayakawa, professor at the International Research Center for Japanese Studies

Whether assuming impossibly contorted positions or tenderly entangled, the myriad couples depicted in shunga indulge both facets of sexual pleasure explained by Hayakawa. The lovers faces convey the conscious, whether that be incredible pleasure or a palpable fear of being caught in the act, while the exaggerated genitalia capture the unconscious, the undeniable, visceral expression of desire. This enlargement is characteristic to shunga, often matching the face sizes of the couples to emphasize the equal importance of the mental and the physical aspects of eroticism. From wild passion and forbidden forays to humorous sexual fumbles and head-scratching acrobatics, shunga celebrates sensual pleasure in every imaginable form.

Translating directly to "spring pictures," shunga first appeared in Japan during the Heian period. Sex scandals of the court or monastery were painted onto to handscrolls and circulated throughout the courtier class. By the Edo period, the genre spread across medium and class, reveling in world of ukiyo-e and widening its audience to nearly every level of society. Released in single-sheet prints or as enpon (books containing twelve images, usually the beginning with suggestive image and becoming increasingly explicit), shunga was an enjoyable and important facet of ukiyo-e printmaking. From landscape to bijin-ga print masters, almost all ukiyo-e designers produced shunga.

While Confucian law ruled public life, shunga joined the sumptuous clothing, lavish prints and forbidden pleasures of the "floating world." Though officially censored by the Shogunate between 1600 and 1900, shunga was not considered impolite or taboo until the rapid modernization and Western influx of the Meiji period. Before this shift, the art form was enjoyed by men and women alike, shared between close friends and lovers, and passed down from parent to child. While some prints might serve an educational purpose, others provided mere titillation or entertainment. Beyond visual enjoyment, shunga also served amuletic purpose: passed from mother to bride as a good luck charm, carried by warriors to protect themselves from death and kept in warehouses to protect stored goods from fire. Evidence shows even lending libraries carried these playful prints, spreading the fun to even the most remote parts of Japan.

[1] Masuda, Aiko. "Shunga: A Unique Treasure Trove of Eroticism from Edo Period." AJW by The Asahi Shimbun. Asahi Shimbun, 12 April 2014. Web. 28 Jan. 2015

Select Sources
http://ajw.asahi.com/article/cool_japan/style/AJ201401040030
http://www.britishmuseum.org/whats_on/past_exhibitions/2013/shunga/about.aspx