in the US and in Japan. Asia outside Japan The Yakuza have been engaged in Southeast Asia since the 1960s; they are working there to develop sex tourism and drug trafficking. This is the area where they are still the most active today. In addition to their presence in Southeast Asian countries such as Thailand, the Philippines, and Vietnam, Yakuza groups also operate in South Korea, China, Taiwan, and in the Pacific Islands (mainly Hawaii). Yakuza groups also have a presence in North Korea; in 2009, Yakuza member Yoshiaki Sawada was released from a North Korean prison after spending five years there attempting to bribe a North Korean official and smuggle drugs. Constituent members According to a 2006 speech by Mitsuhiro Suganuma, a former officer of the Public Security Intelligence Agency, around 60 percent of Yakuza members come from burakumin, the descendants of a feudal outcast class and approximately 30 percent of them are Japanese-born Koreans, and only 10 percent are from non-burakumin Japanese and Chinese ethnic groups. Burakumin The burakumin is a group that is socially discriminated against in Japanese society, whose recorded history goes back to the Heian period in the 11th century. The burakumin are descendants of outcast communities of the pre-modern, especially the feudal era, mainly those with occupations considered tainted with death or ritual impurity, such as butchers, executioners, undertakers, or leather workers. They traditionally lived in their own secluded hamlets and villages away from other groups. According to David E. Kaplan and Alec Dubro, burakumin account for about 70% of the members of Yamaguchi-gumi, the largest Yakuza syndicate in Japan. Ethnic Koreans While ethnic Koreans make up only 0.5% of the Japanese population, they are a prominent part of Yakuza because they suffer discrimination in Japanese society along with the burakumin. In the early 1990s, 18 of 90 top bosses of Inagawa-kai were ethnic Koreans. The Japanese National Police Agency suggested Koreans composed 10% of the Yakuza proper and 70% of burakumin in the Yamaguchi-gumi. Some of the representatives of the designated Bōryokudan are also Koreans. The Korean significance had been an untouchable taboo in Japan and one of the reasons that the Japanese version of Kaplan and Dubro's Yakuza (1986) had not been published until 1991 with the deletion of Korean-related descriptions of the Yamaguchi-gumi. Japanese-born people of Korean ancestry who retain South Korean nationality are considered resident aliens and are embraced by