Concept
Korean units of measurement, called cheokgwan-beop () or cheokgeun-beop () in Korean, is the traditional system of measurement used by the people of the Korean peninsula. It is largely based on the Chinese system, with influence from Japanese standards imposed following its annexation of the Korean Empire in 1910. Both North and South Korea currently employ the metric system. Since 2007, South Korea has criminalized the use of Korean units in commercial contexts but informal use continues, especially of the pyeong as a measure of residential and commercial floorspace. North Korea continues to use the traditional units, although their standards are now derived from metric conversions. Customary Korean units are a local adaption of the traditional Chinese system, which was adopted at a very early date. They were imposed and adjusted at various times by royal statutes. The details of the system have varied over time and location in Korea's history. Standardization—to the extent it occurred—was accomplished by officially sanctioned rulers, ropes, odometers, triangulation devices, weights, cups, and basins. Although most of the measures operate on a decimal system, the standard form was to read out the units of each place (as, e.g., 3 cheok, 1 chon, 4 bun, 1 ri) rather than list them as a single number of the largest unit (as 3.141 cheok). Yi Dan established a Market Bureau (, ) or Bureau of Weights and Measures (, ) at the foundation of the Joseon dynasty in 1392. The Joseon Kingdom later attempted a standardization of length based on square brass rulers, which were used by magistrates and the secret police to fight commercial fraud. Under the Joseon, different classes of society were permitted different numbers of kan in their homes, but in its traditional sense—like the Japanese ken—of a bay between two pillars rather than as a set unit of length. The 1496 Great Codex of State Administration (Kyŏngguk Taejŏn) included a section on approved measures and their verification.