This paper examines the life of Kang Hang (1567–1618), a wartime prisoner who was taken to Japan during the second invasion of the Hideyoshi army in Korea. Contrary to popular belief, Kang was a Confucian hero who taught the Japanese neo-Confucianism and escaped to his homeland to prove his patriotism, I find that Kang had been surrounded by transnational diasporic groups of Koreans, Chinese, Westerners, and cosmopolitan Japanese. While neglecting Korean diasporic networks in Japan, especially a large number of Korean women who had been brought to Japan either as slaves or wives of noble Japanese men, Kang socialized with Japanese intellectuals, including Fujiwara Seika and Akamatsu Hiromitsu in order to gain financial and political support for his return to his imaginary homeland, where he thought he would be welcomed by his friends and king. Yet, after his return to Korea, he faced severe discrimination from his fellow Korean intellectuals who were suspicious of his life spent in the enemy country. Academics and court politicians refused to accept him into the main Seoul circles, and his life was therefore confined to solitary scholarly work such as writing books about Japan and teaching disciples