Six times since World War II the good women of Japan have tried to strip the cloak of legal protection from the backs of their scarlet sisters.

Each time, their efforts have been frustrated, though less and less firmly; male legislators perversely refused to outlaw the ancient profession of prostitution that, with some 500,000 practitioners, flourishes in Japan as it does almost nowhere else. Infamous the world over, Tokyo's thriving red-light districts, ranging from the lacquered pleasure domes of Yoshiwara to the noisome and disreputable turmoil of Shinjuku and Kamedo, have felt the chill winds of reform blow closer and...