A Korean family in Japan has been exchanging letters with its only son for 50 years, ever since he moved to North Korea under a government-sponsored migration project.

The family recently marked the 50th anniversary of his move to North Korea on Aug. 5, 1960. One member, a 55-year-old woman who has asked to be identified by the pseudonym Kang Il Mae, said her only wish is that her brother will come back to Japan.

Kang, who lives in Tokyo, was 5 on that August day when she and her mother saw him off at Niigata port, as he boarded a ship to North Korea. He was one of about 93,000 ethnic Koreans who moved to the country from Japan between 1959 and 1984 through the so-called repatriation project.