Over recent decades, economic living conditions have dramatically improved in South Korea, which now represents one of the most developed nations. At the same time, its twin in the North remains one of the poorest countries on earth. Thus, the Korean peninsula represents a unique historical experiment that allows for study of the effects of environment on human development under a variety of ceteris paribus cultural, genetic and climatic conditions. Previous studies comparing the biosocial performances of the two Koreas have focused on indicators such as weight, height, mid-upper arm circumference and age at menarche. The purpose of the present study was to investigate longevity based on the number of centenarians living in the two Koreas by drawing on censuses implemented around 1925 and 2010. The study found that North Korea had some 0.7 centenarians per one million persons in 1925, and this rate moderately improved to 2.7 around 2010. Conversely, rates skyrocketed in South Korea from 2.7 in 1925 to 38.2 around 2010. This suggests that the rate of centenarians in North Korea around 2010 corresponds to that of South Korea in 1925, suggesting a chronological lag in delayed human development of some 85 years. The prevalence of centenarians is fourteen times higher in contemporary South Korea compared with the North - broadly confirming previous biosocial studies on the two Koreas and two Germanies reporting improved human development in market-oriented systems compared with socialist ones.