Chongryon organises trips by members to North Korea , usually to visit relatives , as well as educational visits for students of Korean schools . They operated '' Mangyongbong-92 '' , a passenger and cargo ferry which linked Niigata in Japan to Wonsan in North Korea , which served as the only direct link between the two countries , and is a subject of much controversy . The ferry was barred from entering the Japanese port for six months in response to North Korea 's July 2006 missile tests and was banned indefinitely following the 2006 North Korean nuclear test
2006 North Korean nuclear test
2006 North Korean nuclear test
Chongryon