Korean units of measurement, calledcheokgwan-beop (Korean: 척관법;Hanja: 尺貫法) orcheokgeun-beop (척근법;尺斤法) in Korean, is thetraditional system of measurement used by the people of theKorean peninsula. It is largely based on theChinese system, with influence fromJapanese standards imposed followingits annexation of theKorean Empire in 1910. BothNorth andSouth Korea currently employ themetric system. Since 2007, South Korea has criminalized the use of Korean units in commercial contexts, but informal use continues, especially of thepyeong 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 thetraditional Chinese system, which was adopted at a very early date.^[1] They were imposed and adjusted at various times by royal statutes.^[2] The details of the system have varied over time and location in Korea's history.^[3][4] Standardization—to the extent it occurred—was accomplished by officially sanctioned rulers, ropes,odometers,triangulation devices,^[5] weights, cups, and basins.

Although most of the measures operate on adecimal 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).^[1]

Taejo of Joseon established a Market Bureau (시사;市司) or Bureau of Weights and Measures (평시서;平市署) at the foundation of theJoseon dynasty in 1392.^[6] TheJoseon Kingdom later attempted a standardization of length based on square brass rulers, which were used bymagistrates and thesecret police to fight commercial fraud.^[7] Under theJoseon, different classes of society were permitted different numbers ofkan in their homes, but in its traditional sense—like the Japaneseken—of abay between twopillars rather than as a set unit of length.^[7]

The 1496 Great Codex of State Administration (Kyŏngguk Taejŏn) included a section on approved measures and their verification.^[1] It employed ali of 360 paces or 2160 feet but did not explicitly mention that conversion until its 1746 supplement.^[1]

The 1897 Law on Weights and Measures uniting Korea's various local systems was the first legislation enacted upon the Joseon's establishment of theKorean Empire.^[8]

During the Japaneseoccupation from 1910 to 1945, Japan imposedits standards on Korea. Two of the most common "traditional" units in Korea—thepyeong offloorspace and the jeweler'sdon—were among those given their modern value by the Japanese.^[9]

South Korea signed theMetre Convention in 1959^[10] and notionallyadopted the metric system underPark Chung Hee on 10 May 1961,^[11][12] with a strict law banning the use of the Korean pound, li,gwan, anddon^[13] effective as of 1 January 1964^[11] and—after metric conversion of theland registries—thepyeong.^[8] The metrication was not applied to imported or exported goods^[11] and remained so generally spotty as to be considered a failure,^[9] with the government abandoning its attempts to enforce the statute by 1970.^[8] The traditional units feature in manyKorean sayings^[a] and much of its literature and poetry, including thenational anthem, which mentions Korea's "three thousand lis of rivers and mountains".^[9] Further attempts to fully metricate occurred in 1983,^[15][13] 2000,^[8] and 2001,^[9] with publicity campaigns praising themetric system and condemning traditional units through TV and radio ads, brochures, signs, and contests.^[16] A common theme was the origin of the present values of the units underJapanese occupation; Yun Byeong-su of theKorea Association of Standards & Testing Organizations noted that "even Japan has forsaken thedon for the units of grams and ounces but here we are standing around like idiots still blathering on aboutdon."^[8] Nonetheless, strong opposition from the construction and jewelry industries and negative media coverage forced Korean politicians to avoid the topic and regulators to settle for dual use of conventional and metric measures.^[8]

A 2006 study found 88% of real estate companies and 71% of jewelers in 7 major markets were still using thepyeong anddon,^[9] after which thegovernment decided simply to criminalize further commercial use of traditional units. (Another important factor was theEuropean Union regulation mandating the use of metric in all imported goods by 2010.)^[17] The sale ofrulers marking Korean feet was ended^[8] and a Measure Act effective 1 July 2007 empowered theKorean Agency for Technology and Standards^[13] of theMinistry of Commerce to begin immediately levying fines of up to₩500,000 for commercial use of thepyeong anddon, with less common units enjoying a longergrace period.^[9] The ban also included use ofAmerican units, such as describing thedisplay size of televisions andcomputer monitors in terms of inches.^[18][b] The "serving size" used as an informal and variable measure of meat cuts was standardized to 100 g.^[8] Knowledge of the fine remained low for years, and it was later increased to a maximum of₩1,000,000 (about$800) for users of illegal units^[16] and₩3,000,000 for sellers of measuring devices marked with unapproved units.^[13] South Korea's measurement standards are now maintained by theKorea Research Institute of Standards and Science.^[13]

Despite this strong official discouragement, some use continues in retail, manufacturing, and farming.^[16] Even among those who have adopted metric units, informal use of awkward metric fractions equivalent to round amounts of the former units is common, especially with regard to the very commonpyeong offloorspace.^[18][8] (Such treatment was avoided in the gold market by laws requiring pricing and denomination in even amounts of grams.)^[8] Another dodge has been to treat the traditional units as a nondescript 'unit', such as marketing an air conditioner appropriate for a 20 py home as a "20-Type".^{[18][unreliable source?]}

Despite the importance of theSoviet Union inestablishing North Korea,Kim Il Sung continued official use of Korean units until the DPRK's notionalmetrication under National Standard 4077–75 on 14 April 1975.^[19][c] It joined theMeter Treaty in 1982^[10] or 1989,^[20] although it was removed from theInternational Bureau for Weights and Measures and related organizations in 2012 for its years of failure to pay the necessary fees.^[21] North Korea has long used the metric system in its state-run media and international publications,^[22] but continues to use traditional units alongside the metric system^[23] in sectors approved by the government.^[24] North Korea's standards are administered by theCentral Institute of Metrology^[19] under theState Administration of Quality Management in accordance with the Law on Metrology^[25] ratified by theSupreme People's Assembly on 3 February 1993.^[26] North Korea uses thepyeong in various regulations, such as the 50 py per person allowed for private farming in 1987,^[27] despite guides who disparage the unit as a historical relic of the South to foreign tourists visiting the country.^[28] The metric system is thought not to have spread to domestic factories or stores prior toKim Jong Un's metrification initiative, announced in May 2013.^[22] The change was part of Kim's policy of stressing the importance of science and technology and its "universal trends".^[22] His announcement in the state-run quarterlyCultural Language Study said that increasing use of the metric system would "strengthen international exchange and cooperation... in the fields of industry, science, and technology and even in the area of general social life".^[22]

The base unit of Korean length is the foot,^[29] with other units changing over time based on its dimensions and multiples. Different ancient Korean kingdoms had different exact measurements;^[7] that ofSejong the Great (r. 1418–1450) was 31.22 cm.[29] Under the earlyJoseon Kingdom, the value of the foot varied by trade, with different lengths used for the carpentry foot and the fabric foot.^[7]

The biggest difference between the traditional Korean and Chinese units of length is that the Korean equivalent of thebu uses a different character and its pre-Tang composition of six Korean feet rather than five. (Thebu was usually treated as a synonym of this unit within Korea but sometimes distinguished as a length of 4 feet). In 369 CE, during the reign ofKing Geunchogo ofBaekje, his realm seems to have used a foot of about 28.85 cm.^[4]

The Korean li previously bore values around 434.16 m (3rd century), 531.18 m (6th–7th), 559.8 m (7th–10th), 552.96 m (10th–14th),^[30] and 450 m (19th);^[31] it was also reckoned based on travel time and therefore varied in length between the plains and mountains.^[31] It was standardized as⁠1/10⁠ of theJapanese ri of3⁠51/55⁠ km in 1905.^[30][d]

The base unit of Korean area is thepyeong,^[29] equivalent to a squarekan or 36 square Korean feet. It comprised about 3.158 m² duringKorea's Three Kingdoms Era;^[7] the present value derives from the units established by the Japanese.^[7] Despite being notionally illegal, thepyeong remains particularly common when discussing residential and commercialfloorspace^[34][35][18] and tiles.^[15] A separatepyeong of 0.09 m² was used for selling glass.^[8] The floorspacepyeong is still prevalent enough that it continues to be glossed in the government's promotional material for foreign investors.^[36]

Farms and large estates were formerly generally measured inmajigi, which is notionally not based on multiples of thepyeong but on the amount of land suitable for the planting of onemall of rice or grain seed.^[37] In practice, it was standardized to thepyeong system but varied in size from province to province based on the average richness of their soil.

The base unit of Korean weight is thegwan.^[29] At the time of Korea's metrification, however, the Geun was in more common use. Although it was usually taken as equivalent to 600 g,^[17] as withred pepper and meats,^[8][7] a separate pound of 400 g was used for fruits^[8][7] and another of 375^[29] or 200 g was used for vegetables.^[8] Thenyang also sees some use among Korea's vendors oftraditional Chinese medicine.^[42]

The "bag" (kama) was a variable unit usually figured as 54 kg ofunhusked rice or 60 kg ofpolished rice, although 90 kg "bags" were also used.^[39]

The base unit of Korean volume or capacity is thedoi.^[29]

In 3rd-centuryGaya, themal was reckoned at about 2 L, the size of the present-daydoe.^[4] In the early 17th century, theJoseon picul was reckoned as 15 or 20mal, but similarly only comprised 89.464 or 119.285 L owing to the smaller size of themal at that time.^[47]

TheUnited Nations also reported a "small mal" half the size of the standardmal.^[32] In contexts involving volume, two cubic forms of "pyeong" were also formerly used. The pyeong of gravel was a cubicgan (about 6.01 m³);^[15] the pyeong of firewood was1⁄3 as much (about 2.0035 m³).^[15]Palais reports alternateseoks of 15 and 20mal each.^[49]

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