Chi (unit)
The chi is a traditional Chinese unit of length. Although it is often translated as the "", its length was originally derived from the distance measured by a human hand, from the tip of the thumb to the tip of the forefinger, and is similar to the ancient span. It first appeared during China's Shang dynasty approximately 3,000 years ago and has since been adopted by other East Asian cultures such as Japan, Korea, and Vietnam. Its present value is standardized at around, although the exact standards vary among the mainland of the People's Republic of China, its special administrative region of Hong Kong, and Taiwan.
In its ancient and modern forms, the chi is divided into 10 smaller units known as cun. 10 chi are equal to 1 zhàng.
Modern values
In mainland China, the chi is been defined as exactly 1/3 of a meter, i.e.,. However, in Hong Kong the corresponding unit, pronounced tsek in Cantonese, is defined as exactly, or. 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.,.
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, the value of the chi varied between. 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 the 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 the chi, depending on the part of the country and the application, varied between. According to an 1864 British report, in most of China the chi used by engineers in public works was equal to, the surveyors' chi was, while the value generally used for measuring distances was. In Guangzhou, however, the chi used for local trade varied from – 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.
In 1905 the Korean Empire defined the cheok as 10000/33000 of a meter. In 1964, South Korea fully adopted SI units.
Usage in Chinese language
Due to its long history and its widespread usage, chi 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 jìn chǐ" means "extremely greedy".In informal use in China, chi is also sometimes used to refer to the United States customary foot or British imperial foot.