Li (unit)

The li, also known as the Chinese mile, is a traditional unit of distance used in East Asia. It serves as a way to measure how far apart places are. The name of the unit comes from two characters. One character represents "field" and the other represents "earth." This combination suggests the li was once considered the length of a single village. While it is a traditional unit, its actual length has changed many times throughout history. Today, the li is standardized to exactly 500 meters, which is half a kilometer.

To understand how the li works, we must look at its smaller components. One li is divided into 1,500 chi, which are often called "Chinese feet." This hierarchical system allows for more precise measurements of shorter distances. Historically, the li was not always a fixed value. As late as the 1940s, a li could vary depending on the effort required to travel a certain distance. This meant the measurement was sometimes tied to the difficulty of the terrain. This is similar to how a Western league was used in the past.

Measurement standards have shifted through many different Chinese dynasties. Legend says the Yellow Emperor established these measures around 2600 BC. Later, Yu the Great of the Xia dynasty standardized them roughly 600 years later. During the Spring and Autumn and Warring States periods, the value varied by state. Before the Qin dynasty, historians estimate the li was about 405 meters. The Qin dynasty attempted to impose a standard, setting the li at 360 paces, or bu. However, they changed the number of chi per bu from 6 to 5, which shortened the unit.

Following the Qin, the Han dynasty standardized the li at 415.8 meters. This value remained stable through the Qin and Han periods. In 1924, researchers discovered a bronze imperial standard measure in Beijing. This artifact dates to AD 9 and was kept in the Imperial Palace. This discovery allowed historians to make very accurate conversions to modern metric units. These findings were confirmed by archaeological rulers and measurements between known geographic points. The work of scholars like Dubs helped confirm the precise Han li measurement.

The value of the li continued to evolve through the centuries. During the Tang dynasty, the li was approximately 323 meters. In the Qing dynasty, the number of chi per li increased from 1,500 to 1,800. This made the Qing li much longer, measuring about 644.6 meters. The Qing also added a larger unit called the tu, which equaled 150 li. In the 20th century, the Republic of China adopted the metric system in 1928. Later, the People's Republic of China used the traditional units to show cultural pride. They officially restandardized the li to the modern 500-meter value in 1984.

The li appears frequently in Chinese culture, literature, and geography. It is often used to describe massive or immeasurable distances. For example, one name for the Great Wall is the "Ten-Thousand-Li Long Wall." This is a figurative use of the number ten thousand. In reality, the modern Great Wall is about 42,000 li long. The unit also appears in famous proverbs. One famous saying from the Tao Te Ching states that a journey of a thousand li begins with a single step. Even mythical creatures like the "thousand-li horse" use this unit to show incredible speed.

Other East Asian nations also use versions of the li. Japan and Korea adopted measurements based on the Tang dynasty li. In Japan, the ri evolved to represent the distance a person could walk in one hour on mountain roads. By the Edo period, the Tokugawa shogunate defined 1 ri as 36 cho. In 1891, the Japanese government fixed the ri to the metric system at about 3.93 kilometers. In Korea, the term "Three Thousand Li" is a poetic name for the entire peninsula. This is because the distance from the north to the south is roughly 1,200 km.