From The Brooklyn Museum's HIROSHIGE ONE HUNDRED FAMOUS VIEWS OF EDO:  It is a murky winter night as the Oumayagashi ferry approaches its landing on the west bank of the Sumida just north of the Asakusa rice granaries of the bakufu.  Against this somber background, the white faces, red sashes and blue head-towels of the two women in the bow of the ferry stand out in bright relief.  These are yotaka, "night hawks," the lowest class of street prostitutes.  They are accompanied by their gyu, perhaps a father or brother, who served as bodyguard and tout.  This scene is the closest Hiroshige ever gets to depicting the harsh realities of lower-class life in Edo, and he does so in a way calculated not to offend.