In the early stages of the war, Japanese authorities recruited prostitutes through conventional means. In urban areas, conventional advertising through middlemen was used alongside kidnapping. Middlemen advertised in newspapers circulating in Japan and in the Japanese colonies of Korea, Taiwan, Manchukuo, and China. These sources soon dried up, especially in metropolitan Japan.;</ref> The Ministry of Foreign Affairs resisted further issuance of travel visas for Japanese prostitutes, feeling it tarnished the image of the Japanese Empire..</ref> The military turned to acquiring comfort women outside mainland Japan, mostly from Korea and from occupied China. An existing system of licensed prostitution within Korea made it easy for Japan to recruit females in large numbers.