evidence: Efforts have been made throughout North Korea’s history to increase low labour productivity. In the late 1950s the state adopted a mass-mobilization measure called the Ch’ŏllima ("Flying Horse") movement that was patterned on China’s Great Leap Forward of 1958–60. Subsequently, in the early 1960s, programs were instituted in agricultural and industrial management, called respectively the Ch’ongsan-ni Method and Taean Work System. In the late 1990s the country adopted the official goal of building a strong military and a prosperous economy, adopting the motto "Kangsŏng taeguk" ("Strong and prosperous nation"). Under this slogan Kim Jong Il paid meticulous attention to the military, his primary base of power, while opening parts of the economy to accommodate foreign investment and trade. North Korea even allowed parts of its territory to be used by foreign (South Korean) businesses, including the sightseeing areas around Mount Kŭmgang, in the southeast, and the Kaesŏng Industrial Complex, in the southwest. However, the operation of these enclosed and restricted areas, known as special economic districts (gyŏngje t’ŭkgu), was conducted strictly under North Korean supervision and was only for the purpose of collecting foreign currencies (mainly U.S. dollars), not as part of the country’s overall economic activity.