Chi (unit)
Encyclopedia
The chi is a traditional Chinese
unit of length
, approximately equal to one foot. Its length is derived from the length of human forearm and has first appeared during the Shang Dynasty
approximately 3000 years ago. Since then it has spread to and adopted by other East Asian cultures, such as Japan, Korea and Vietnam. It is further divided into 10 smaller units called cun
, analogous to an inch
; 10 chi make up one zhang .
chi has been defined since 1984 as exactly 1/3 of a meter, i.e. 33 1/3 cm (approximately 1.094 ft). However, in the Hong Kong SAR the corresponding unit, pronounced chek in Cantonese, is defined as exactly 0.371475 m (exactly 14 5/8 in).
The two units are sometimes referred to in English as "Chinese foot" and "Hong Kong foot".
In Taiwan
, chi is the same as the Japanese shaku, i.e. 10/33 of meter (30 1/3 cm).
to Han Dynasty
to Kingdoms of Wu
and Wei
), the value of the chi varied between 23.1 to 24.3 cm. Even earlier, during the Warring States era, the value of chi was essentially the same.
It is thought that the ancient Chinese astronomers also used chi as an angular unit; modern analysis of historical records indicates that it may have been equal to one degree
.
In the 19th century, the value of chi, depending on the part of the country and the application, varied between 31 and 36 cm. According to an 1864 British report, in most of China the chi used by engineers in public works was equal to 12.71 English inch (32.28 cm), the surveyors' chi was 12.058 inch (30.62 cm), while the value generally used for measuring distances was 12.17 inch (30.91 cm). In Guangzhou
, however, the chi used for local trade varied from 14.625 to 14.81 inch (
37.15-37.62 cm) - i.e., very close to the modern chek; the value fixed by a Sino-British treaty for the purposes of customs duties in Hong Kong was 14.1 inch (35.81 cm).
Chinese units of measurement
Chinese units of measurement are the customary and traditional units of measure used in China. In the People's Republic of China, the units were re-standardised during the late 20th century to make them approximate SI units. Many of the units were formerly based on the number 16 instead of 10...
unit of length
Length
In geometric measurements, length most commonly refers to the longest dimension of an object.In certain contexts, the term "length" is reserved for a certain dimension of an object along which the length is measured. For example it is possible to cut a length of a wire which is shorter than wire...
, approximately equal to one foot. Its length is derived from the length of human forearm and has first appeared during the Shang Dynasty
Shang Dynasty
The Shang Dynasty or Yin Dynasty was, according to traditional sources, the second Chinese dynasty, after the Xia. They ruled in the northeastern regions of the area known as "China proper" in the Yellow River valley...
approximately 3000 years ago. Since then it has spread to and adopted by other East Asian cultures, such as Japan, Korea and Vietnam. It is further divided into 10 smaller units called cun
Cun (length)
The cun is a traditional Chinese unit of length. Its traditional measure is the width of a person's thumb at the knuckle, whereas the width of the two forefingers denotes 1.5 cun and the width of all fingers side-by-side is three cuns...
, analogous to an inch
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
; 10 chi make up one zhang .
Modern values
In People's Republic of ChinaPeople's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
chi has been defined since 1984 as exactly 1/3 of a meter, i.e. 33 1/3 cm (approximately 1.094 ft). However, in the Hong Kong SAR the corresponding unit, pronounced chek in Cantonese, is defined as exactly 0.371475 m (exactly 14 5/8 in).
The two units are sometimes referred to in English as "Chinese foot" and "Hong Kong foot".
In Taiwan
Taiwanese units of measurement
Taiwanese units of measurement are the customary and traditional units of measure used in Taiwan. Many of the units derive from Japanese units of measurement and have similar names as Chinese units of measurement but different conversions than in China or Hong Kong...
, chi is the same as the Japanese shaku, i.e. 10/33 of meter (30 1/3 cm).
Historical values
The study of ancient rulers and other artifacts whose size in the contemporary chi was known allowed modern researchers to surmise that during the 2nd century BC to 3rd century AD the (Qin DynastyQin Dynasty
The Qin Dynasty was the first imperial dynasty of China, lasting from 221 to 207 BC. The Qin state derived its name from its heartland of Qin, in modern-day Shaanxi. The strength of the Qin state was greatly increased by the legalist reforms of Shang Yang in the 4th century BC, during the Warring...
to Han Dynasty
Han Dynasty
The Han Dynasty was the second imperial dynasty of China, preceded by the Qin Dynasty and succeeded by the Three Kingdoms . It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han. It was briefly interrupted by the Xin Dynasty of the former regent Wang Mang...
to Kingdoms of Wu
Eastern Wu
Eastern Wu, also known as Sun Wu, was one the three states competing for control of China during the Three Kingdoms period after the fall of the Han Dynasty. It was based in the Jiangnan region of China...
and Wei
Cao Wei
Cao Wei was one of the states that competed for control of China during the Three Kingdoms period. With the capital at Luoyang, the state was established by Cao Pi in 220, based upon the foundations that his father Cao Cao laid...
), the value of the chi varied between 23.1 to 24.3 cm. Even earlier, during the Warring States era, the value of chi was essentially the same.
It is thought that the ancient Chinese astronomers also used chi as an angular unit; modern analysis of historical records indicates that it may have been equal to one degree
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
.
In the 19th century, the value of chi, depending on the part of the country and the application, varied between 31 and 36 cm. According to an 1864 British report, in most of China the chi used by engineers in public works was equal to 12.71 English inch (32.28 cm), the surveyors' chi was 12.058 inch (30.62 cm), while the value generally used for measuring distances was 12.17 inch (30.91 cm). In Guangzhou
Guangzhou
Guangzhou , known historically as Canton or Kwangchow, is the capital and largest city of the Guangdong province in the People's Republic of China. Located in southern China on the Pearl River, about north-northwest of Hong Kong, Guangzhou is a key national transportation hub and trading port...
, however, the chi used for local trade varied from 14.625 to 14.81 inch (
37.15-37.62 cm) - i.e., very close to the modern chek; the value fixed by a Sino-British treaty for the purposes of customs duties in Hong Kong was 14.1 inch (35.81 cm).
Usage in Chinese
Due to its long history and its widespread usage, chi (along with cun) has also seen metaphorical usages in the Chinese language. For example, chi cun , a word made up of the units chi and cun, refers to the dimensions of an object, while the idiom "dé cùn jùn chǐ" means "extremely greedy".See also
- Shaku (unit) - the corresponding unit in JapaneseJapanese languageis a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
- Chinese units of measurementChinese units of measurementChinese units of measurement are the customary and traditional units of measure used in China. In the People's Republic of China, the units were re-standardised during the late 20th century to make them approximate SI units. Many of the units were formerly based on the number 16 instead of 10...
- Taiwanese units of measurementTaiwanese units of measurementTaiwanese units of measurement are the customary and traditional units of measure used in Taiwan. Many of the units derive from Japanese units of measurement and have similar names as Chinese units of measurement but different conversions than in China or Hong Kong...