Authentic Edo period original, c.1845, Japanese shunga erotic art woodblock print by Koikawa Shozan (1821-1907).  From the shunga series, Tokaido goju san tsugi, an erotic parody of Hiroshige's 53 Stations of the Tokaido.  Here, in this shunga series, one and the same man ventures to various stations of the Tokaido while having sex with a different woman at each station. 
Shunga picture measures 17.5 cm x 21.1 cm.  Very good colors and impressions.  Condition is decent with some wear and soiling.  No backing.  Please see and judge from photos.