Authentic Edo period original from the Kansei era, c.1789, Japanese erotic art shunga woodblock print picture book by Maruyama Ōkyō (1733 - 1795).  Title of book is Ehon Meoto Zue. 
Shunga picture book measures 15.4 cm x 21.3 cm closed.  Very good impressions and good condition with some wear and soiling; one shunga close-up scene has some added coloring to it.  That being said, both the shading and coloring are quite nice and clearly done by an artist with some know-how and expertise.  All pictures are shown here (16 total picture pages) with remaining pages being kanji text pages.  Please see and judge from photos.
 
A very rare antique Japanese shunga book featuring some skillfully well-done, extra-large coitus close-ups!
 
About the artist:  Maruyama Ōkyō (1733–1795) was a pioneering Edo-period artist and the founder of the Maruyama-Shijō school, renowned for his innovative blend of Western realism and traditional Japanese aesthetics.  While he is celebrated for his lifelike depictions of landscapes and animals, Ōkyō also created shunga (erotic art) that reflect his mastery of detail and expressive composition.  His shunga works are notable for their refined elegance and subtle sensuality, combining naturalistic anatomy with dynamic storytelling.  As a visionary who pushed the boundaries of Japanese art, Ōkyō’s influence endures, and his works—both conventional and erotic—are highly prized for their technical brilliance and artistic sophistication.