Life is inseparable from rulers, building houses, measuring land, making clothes and so on. According to Lu Chunqiu Ji Gu Le, ancient Chinese people determined the length of rulers according to the length of musical instruments with "yellow bell" melody, so ancient rulers were also called musical ruler, metrical ruler and yellow bell ruler. It is the basis of measurement. Later generations had different scales.
Rulers exist in ancient and modern times, but the quantity (actual length) is different. For example, the article "Zou Ji satirizes the king of Qi and can be remonstrated" says: "Zou Ji has repaired more than eight feet." If calculated with a modern ruler, Zou Ji's body length is more than 2.66 meters, which is obviously too high.
Obviously, the ancient ruler is shorter than the modern ruler. The original ruler refers to the distance between a man's thumb and middle finger, which is about 20 cm. The ruler of the Zhou Dynasty is 19.8+0 cm in modern times. By the Warring States period, one foot was about 22. 12 cm in modern times, but at that time, countries were not completely consistent. For example, the Chu foot unearthed during the Warring States period is 22.7 cm long.