Main Street of Yoshiwara, Tokyo in 1896, from “Yankees of the East”

The Yoshiwara district was bordered on all sides by a moat and accessed by gates on either side. Although the bordellos of yesteryear are no more, the sex-trade persists, now in the form of ‘soaplands’, which serve a similar function. See: A walk in the sex park: Yoshiwara and the Tokyo bordello