Traditionally, most East Asian countries have had few scruples with regard to extramarital sex as far as males were concerned, but before 1900, Japan was remarkable in the development of commercial prostitution on a grand scale.Koreans may want to blame Japan for commercializing prostitution in Korea, but Japan can hardly be blamed for the growth of prostitution everywhere else in East, Southeast, and South Asia, except insofar as it led the way in creating a model of economic growth that spread the wealth beyond a narrow elite.
In this regard it was different from Korea, where in old times only the rich and famous could afford to buy expensive sexual services from gisaeng girls, while the "low orders" usually had no access to commercial sex whatsoever.
The Korean nationalists love to stress this fact, explaining it as another indication of the alleged "spiritual purity" of Koreans. Well, less lofty explanations are more likely, but it is difficult to deny that the large-scale prostitution industry was created by the Japanese presence.
In the 1850s, Japan was "opened" to the world, but for decades afterward it remained a very poor place, so ``export-oriented'' prostitution became a major industry there.
The Japanese working girls, known as "karayuki-san" ("those going overseas"), plied their trade across Asia, from Sydney to Vladivostok, from Shanghai to Singapore, usually supervised by Japanese brothel owners.
A Japanese prostitute and brothel remained ubiquitous components of urban life in the Asia-Pacific for the decades between 1870 and 1920, and remittances from these girls, who duly sent their earnings back home, were said to be the third biggest foreign currency earner for Japan at the turn of the 20th century.
Of course, neighboring Korea became one of the areas where Japanese prostitution flourished. Contrary to the now common misperception, typical commercial sexual encounters in Korea before 1900 did not involve a poor Korean girl serving some lusty Japanese male.
If anything, the situation in which a Korean male purchased sex from a Japanese female was probably more common. Until the 1910s, the vast majority of prostitutes operating in the country were Japanese.
via The Marmot