Sin worked as a lathe operator.[2] She was separated from her father in 1950 during the Korean War. He lived in South Korea.[3] She was described as tall and long-striding.[2]
Excluding 1965, Sin was ranked in the top 10 in the world from 1959 to 1967 at 400 m,[4] and from 1960 to 1967 in 800m.[5] In October 1960, she surpassed the 400 metres world record with an unratified time of 53.0.[6] She won the 400 m at the Brothers Znamensky Memorial meeting in Lenin Stadium, Moscow, in 1961, 62, and 63.[7] At Pyongyang in 1962, she ran 400 m in 51.9 s, becoming the first woman to break the 53-second barrier and 52-second barrier.[8] Of her eight claimed world record marks, this would be the only one ratified.[9][10] A note in the 1964 British Athletics yearbook states, "The IAAF are withholding recognition of a time of 53.1 by Betty Cuthbert on 11.3.63 pending investigation of Sin Kim Dan's 51.9; meanwhile there is no official world record."[11]
Sin represented North Korea at the GANEFO (Games of the New Emerging Forces) in 1963 and 1966, winning gold in the 200 m, 400 m, and 800 m at both games.[12] Her 1963 times of 51.4 (400 m) and 1:59.1 (800 m) bettered the world records, the latter the first woman under 2 minutes.[13] They were never ratified by the IAAF, however, as GANEFO was not an approved competition.[14]
Sin's personal bests were set in 1964 in Pyongyang, at 51.2 for 400 m and 1:58.0 for 800 m.[1][14] The IAAF suspended GANEFO competitors, effectively barring Sin from the 1964 Summer Olympics in Tokyo.[3][15] Sin was reunited with her father at Haneda Airport for a few minutes before being turned back from Japan.[3]Ann Packer won the Olympic 800 m in a new official world record of 2.01.1.[16]
Finally there was Sin Kim Dan, a delicate little North Korean lass who broke the women's records at both 400 meters and 800 meters two years ago; some time later, an overjoyed elderly gentleman in South Korea recognized Sin as the son he had lost in the war.
^Schaffer, Kay; Smith, Sidonie (2000-08-01). "One Chromosome Too Many?". The Olympics at the Millennium: Power, Politics, and the Games. Rutgers University Press. p. 146. ISBN9780813528205. Retrieved 5 May 2012.
