yūkaku

thumb|right|A in Tokyo, 1872

were legal red-light districts in Japanese history, where both brothels and prostitutes - known collectively as , the higher ranks of which were known as oiran - recognised by the Japanese government operated. Though prostitution was, officially, legal to engage in and pay for only in these areas, there were a number of places where prostitutes and brothels operated illegally, known as , the generic name for all unlicensed red-light districts other than Yoshiwara (later including both Shimabara and Shinmachi).