Jin (mass)

The jin (Chinese: 斤; pinyin: jīn)^[a] or catty (from Malay kati) is a traditional Chinese unit of mass used across East and Southeast Asia, notably for weighing food and other groceries. Related units include the picul (dan or shi), equal to 100 catties, and the tael (liang), which is 1⁄16 of a catty. The stone (also dan or shi) is a former unit used in Hong Kong equal to 120 catties, and a gwan (鈞) is 30 catties. The catty is still used in Southeast Asia as a unit of measurement in some contexts, especially by the significant Overseas Chinese populations across the region, particularly in Malaysia and Singapore.

The catty is traditionally equivalent to 1+1⁄3 pound avoirdupois, formalised as 604.78982 grams (g) in Hong Kong,^[1] 604.5 g (historically) in Vietnam,^[2] 604.79 g in Malaysia^[3] and 604.8 g in Singapore.^[4] In Taiwan,^[5] Japan, Korea,^[6] and Thailand, the unit is rounded to 600 g. In China, the jin is rounded to 500 g and called the market catty (市斤; shìjīn), to distinguish it from the kilogram (called the common catty; 公斤; gōngjīn), and is subdivided into 10 taels rather than 16.

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

The mass of the jin varies between different eras and regions, but its ratio to contemporaneous units is generally unchanged: one jin is equal to sixteen liang, or 1/120 of a dan. Starting from the late Qing dynasty, the jin was also written in English as catty or kan based on the Malay name for the unit.^[11]

Before the Qing dynasty, various regions and industries in China had their own weight standards for jin and liang. During the Qing, unified weights and measures were implemented. One late-Qing jin was 596.816 g according to the Beiyang government, and equal to 16 liang.^[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 on Qing definitions (营造尺库平制),^[12][13] with the liang as the base 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, the Nationalist government adopted and promulgated The Weights and Measures Act^[14] to adopt the metric system and limit the updated Chinese units of measurement to private sales and trade, effective 1 January 1930. The updated market units are based on rounded metric numbers, and jin is the base unit.^[15]

On June 25, 1959, the State Council of the People's Republic of China issued the Order on the Unified Measurement System, retaining the market system, with the statement of "the market system originally stated that sixteen liang is equal to one jin. Due to the trouble of conversion, it should be changed to ten liang per jin."^[16][17]

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

Until 1979, traditional Chinese medicine (TCM) generally kept the division of 16 liang 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-used qian was to be treated as exactly 3 g, with other units derived from the liang 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]

The jin, or kin, in Taiwan is called the Taiwan jin or taijin (台斤). The taijin is equivalent to the Qing-era Chinese jin. 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 the Taiwan system. 1 taijin is 600 grams, or 16 Taiwan liang, and 1 Taiwan liang is equal to 37.5 g.^[20]

According to the original Hong Kong law, Article 22 of 1884, one jīn is 1+1⁄3 British pounds (that is, 3 jīn is equal to 4 pounds). Currently,^[when?] Hong Kong law stipulates that one jīn is equal to one hundredth of a dan or sixteen liang, which is 0.604 789 82 kilograms^[1] (0.604 789 82 kg divided by 4⁄3 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 British troy 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 one jin, or catty, is also equal to 1 1⁄3 pounds, which is equal to sixteen liang (or taels) or 0.6048 kg.^[4]

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

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

In Vietnam, the jin is called the cân 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:

• The cân ('scale') is also called cân 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 (Chinese jin; lit. 'market jin'): Or simply called jin, also called Chinese pound. In the market system (市制) in use since 1930, 1 jin equals 500 g.
• 公斤 (kilogram, lit. 'common jin'): A metric unit, equivalent to 1000 g.^[37]
• 磅 (pound): A British Imperial unit, about 453.6 g.

1 Chinese jin equals 0.5 kg, or 1.1023 pounds in China.^[37]

The word catty comes from Malay kati, meaning 'the weight'. It has also been borrowed into English as caddy, 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 in Sanchong, New Taipei, Taiwan
• 
  Tea priced by the catty in Dadaocheng, Taipei, Taiwan
• 
  A spring scale in Hong Kong with conversions between the metric system (red), traditional Chinese units (green) and Imperial 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)