Chi (unit)

The chi (Tongyong Pinyin chih) is a traditional Chinese unit of length. Although it is often translated as the "Chinese foot", 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 (shaku), Korea (ja/cheok), and Vietnam (thước). Its present value is standardized at around one-third meter (1 ft 1 in), 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 (the "Chinese inch"). 10 chi are equal to 1 zhàng.