Thejin (Chinese:斤;pinyin:jīn)^[a] orcatty (fromMalaykati) is atraditional Chinese unit ofmass used acrossEast andSoutheast Asia, notably for weighing food and other groceries. Related units include thepicul (dan orshi), equal to 100 jin, and thetael (liang), which is1⁄16 of a jin. Thestone (alsodan orshi) is a former unit used inHong Kong equal to 120 jin, and agwan (鈞) is 30 jin. The jin is still used in Southeast Asia as a unit of measurement in some contexts, especially by the significantOverseas Chinese populations across the region, particularly inMalaysia andSingapore.

The jin is traditionally equivalent to1+1⁄3pound avoirdupois, formalised as 604.78982 grams (g) in Hong Kong,^[1] 604.5 g (historically) inVietnam,^[2] 604.79 g in Malaysia^[3] and 604.8 g in Singapore.^[4] InTaiwan,^[5]Japan,Korea,^[6] andThailand, the unit is rounded to 600 g. InChina, thejin is rounded to 500 g and called themarket jin (市斤;shìjīn), to distinguish it from the kilogram (called thecommon jin;公斤;gōngjīn), and is subdivided into 10 taels rather than 16.

In ancient China, the office ofSima (司馬) was in charge of military affairs. Because the management of military grain andfodder involved frequent weighing, mass units (such asjin andliang) were also calledsima jin (司馬斤),sima liang, and so on. The measuring tools used were calledsima scales (司馬秤). This is still true in Hong Kong. Onesima jin is equal to sixteensima liang, which is where theidiom "half a jin vs eight liang"^{[b][7][better source needed]} comes from.^[8][9]

The mass of thejin varies between different eras and regions, but its ratio to contemporaneous units is generally unchanged: onejin is equal to sixteenliang, or 1/120 of adan. Starting from the lateQing dynasty, thejin was also written in English ascatty orkan based on theMalay name for the unit.^[11]

Before the Qing dynasty, various regions and industries in China had their own weight standards forjin andliang. During the Qing, unified weights and measures were implemented. One late-Qingjin was 596.816 g according to theBeiyang government, and equal to 16liang.^[12]

On 7 January 1915, the Beiyang government promulgated a measurement law to use the metric system as the standard but also a system based directly onQing definitions (营造尺库平制),^[12][13] with theliang as thebase unit.

Market-unit system
A traditional Chinese scale
Chinese	市制
Literal meaning	market system
Transcriptions Standard Mandarin Hanyu Pinyin shìzhì Wade–Giles shih-chih
Alternative Chinese name
Chinese	市用制
Literal meaning	market-use system
Transcriptions Standard Mandarin Hanyu Pinyin shìyòngzhì Wade–Giles shih-yung-chih

On 16 February 1929, theNationalist government adopted and promulgatedThe Weights and Measures Act^[14] toadopt the metric system and limit the updated Chinese units of measurement to private sales and trade, effective 1 January 1930. The updatedmarket units are based on rounded metric numbers, andjin is the base unit.^[15]

On June 25, 1959, theState Council of the People's Republic of China issued theOrder on the Unified Measurement System, retaining the market system, with the statement of "the market system originally stated that sixteenliang is equal to onejin. Due to the trouble of conversion, it should be changed to tenliang perjin."^[16][17]

Legally, 1jin equals 500 grams, and 10liang equals 1jin (that is, 1liang is 50 g). Thetraditional Chinese medicine measurement system was unchanged.^[16][17]

Until 1979, traditional Chinese medicine (TCM) generally kept the division of 16liang to 1 (500-g)jin. In 1979, the State Council of China issued an order for the TCM trade to switch to metric units. The previously usedqian was to be treated as exactly 3 g, with other units derived from theliang scaled accordingly.^[18] Mass units in ancient TCM prescriptions should be interpreted using the metric (gram) conversions appropriate for the era, not the modern versions of these units.^[19]

Thejin, orkin, in Taiwan is called theTaiwan jin ortaijin (台斤). Thetaijin is equivalent to the Qing-era Chinesejin. In 1895 Taiwan was ceded to Japan, which implemented the metric system, but Taiwan continued to use the old weights and measures. Thus, after China stopped using the Qing system, it came to be known as theTaiwan system. 1taijin is 600 grams, or 16 Taiwanliang, and 1 Taiwanliang is equal to 37.5 g.^[20]

According to the original Hong Kong law, Article 22 of 1884, onejīn is1+1⁄3British pounds (that is, 3jīn is equal to 4 pounds). Currently,^[when?] Hong Kong law stipulates that onejīn is equal to one hundredth of adan or sixteenliang, which is 0.604 789 82 kilograms^[1] (0.604 789 82 kg divided by4⁄3 is 0.453 592 65 kg, the 1878 definition of the British Avoirdupois pound).

These are used for trading precious metals such as gold and silver, defined around the Britishtroy weight system.

Malaysia has the same regulations as it is a former British colony.^{[clarification needed]} The rounding is slightly different, as 0.604 79 kg. Similarly, Singapore law stipulates that onejin, or catty, is also equal to 1 1⁄3 pounds, which is equal to sixteenliang (ortaels) or 0.6048 kg.^[4]

In Japan, 1jin, orkin in Japanese, is equal to 600 grams, but is rarely used. An exception is thejin used for slices of bread. According to the fair competition regulations of the Japanese Bread Fair Trade Council, ajin only needs to be more than 340 g.^[25]

The base unit of Korean mass is thegwan.^[26] At the time ofKorea's metrication, however, thegeun (or Korean pound) was in more common use. Thegwan is usually considered equivalent to 600 g.^[27] Thenyang also sees some use among Koreantraditional Chinese medicine vendors.^[28]

In Vietnam, thejin is called thecân ta (lit. 'our scale'), and is equal to 604.6 grams. The following table lists common units of mass in Vietnam in the early 20th century:[34]

Notes:

• Thecân ('scale') is also calledcân ta ('our scale') to distinguish it from the kilogram (cân tây, 'Western scale').^[36]

The jin, pound and kilogram are all currently used in China. Their meanings and conversions in China are as follows:^[37]

• 市斤 (Chinesejin; lit. 'marketjin'): Or simply calledjin, also calledChinese pound. In themarket system (市制) in use since 1930, 1jin equals 500 g, equivalent to 1.1023 pounds.^[37]
• 公斤 (kilogram, lit. 'commonjin'): A metric unit, equivalent to 1000 g.^[37]
• 磅 (pound): A British Imperial unit, about 453.6 g.

The wordcatty comes from Malaykati, meaning 'the weight'. It has also been borrowed into English ascaddy, meaning a container for storing tea.

• wikt:幾斤幾兩 (jǐjīnjǐliǎng)
• wikt:半斤八兩 (bànjīnbāliǎng)
• wikt:缺斤少兩 (quējīnshǎoliǎng)
• wikt:斤斤計較 (jīnjīnjìjiào)

• 
  Fruit sold in catties in a market inSanchong, New Taipei, Taiwan
• 
  Tea priced by the catty inDadaocheng, Taipei, Taiwan
• 
  Aspring scale in Hong Kong with conversions between themetric system (red),traditional Chinese units (green) andImperial units (in blue)

• Chinese units of measurement
• Japanese units of measurement
• Korean units of measurement
• Taiwanese units of measurement
• Vietnamese units of measurement

From Chinese Wikipedia:

• 中國度量衡#衡 (Chinese mass units)
• 市制 (market system)
• 斤 (jin)

• Units of mass
• Chinese units of measurement
• Customary units of measurement
• Chinese units in Hong Kong

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