The Japan that makes public for some time afore is invaded China during company limited of China north traffic in thousands of pieces of photograph, a group of caption are " outside front door first-class prostitute house " photograph. These photographs should be to film at the south main at that time prostitute house area outside front door, what basically center over there is first-class with second-class advanced place. Nevertheless those photographs are black and white, the chromophotograph that everybody sees today is by " love history " exclusive later period connects those who undertake chromatically is handled through computer. According to be opposite at that time the standard of room of Beijing prostitute shop administers regulation, first-class place makes an appointment with 80, second-class place 100, third class place makes an appointment with 180, the 4 limitation that wait for 20 to undertake an amount go up. The main reason with concentrated house of the prostitute outside front door is here is next to commerce and hotel area, have safeguard to consuming a crowd. According to Germany Buddhist nun. Of Gan Bo " the society of Beijing is investigated " , 1919 when Beijing is registered at that time have from woman of course of study 3130 people, prostitute house 377, but actual number far this over number. Pleasant rich estimation should exceed 7000 people, plus dark door child was to exceed 10 thousand people more. So that Gan Bo sighs with emotion,is in 81 people of Beijing at that time from woman of course of study, there is one person in every 21 women is from woman of course of study, the scale of other big city on outclass world. At that time the transmission to prevent venereal disease, ever asked each wait to want to have regular examination from woman of course of study. But the delegate of first-class prostitute house puts forward to avoid check to the police however, think first-class receive a visitor from woman of course of study relatively high end, sicken number is so less. Final police still accepted the demand of first-class firework woman really, they need every months to issue guarantee only, and pay earnest money, lest grant every months,can accept an inspection.