The square grid of the Yoshiwara bordello district in Edo (now Tokyo). The 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. Also, the street grid is identical to the way it was in the past, except now there no moat. See: A walk in the sex park: Yoshiwara and the Tokyo bordello