Around 1830, the slave trade almost disappeared and was replaced by the rise of China and Indian laborers. China workers and Indian laborers generally go alone, and where they stay, young and middle-aged men are highly concentrated, and the ratio of male to female is seriously out of balance. Hard and boring work and life need to find an outlet to solve physical desires. A large number of Chinese laborers and Indian laborers flow to form an urban society, which provides a broad market for the existence and development of prostitutes. Because of this, the expansion of "Nanyang Sister" to all parts of the world basically overlaps with the areas where Chinese workers and Indian laborers are active. On the other hand, in the view of European colonists as managers, the existence of Japanese prostitutes is a kind of "soft" lubricant, which can adjust the boring and monotonous life of workers and let them work with peace of mind. For this reason, for a long time, they acquiesced in and even welcomed and supported Japanese prostitutes. At that time, Japanese media also organically put China, a "world labor country", and Japan, a "world prostitution country", and expounded the profound "karma" relationship between China and Japan.