The ancient working people divided a day and night into twelve periods, and each period was called an hour. Twelve o'clock can refer to either a day or any time. Twelve o'clock was created by the ancient working people in China according to the natural laws of the sun, the changes of the sky and the daily production activities and living habits.

This is the twelve-hour system used in the Western Zhou Dynasty. In the Han Dynasty, it was named Midnight, Crow, Pingdan, Sunrise, Food Time, Horn, Japan-China, Sundial, Sunset, Dusk and Man's Decision. It is also expressed by the twelve earthly branches, and it is the child time from 23: 00 to 1 at midnight, the ugly time from 1 to 3: 00, and the Yin Shi time from 3: 00 to 5: 00, which are recursive in turn.

Twelve o'clock direction

Twelve o'clock consists of twelve specific time nouns. People can find the source of these words from the ancient books of China in the pre-Qin period. Before the Han Dynasty, these appellations were different. Until the early Han Dynasty, China implemented the taichu calendar Law. "Twelve o'clock a day, the main branch is the subject." (Zhao Yi's Examination of Jade Cong, Volume 34) Basic stereotypes and naming.

The twelve o'clock calendar is unique and has a long history. It is an outstanding contribution of the Chinese nation to the astronomical calendar of mankind and one of the splendid treasures of Chinese culture. At twelve o'clock, the twelve-point regimen of Huangdi Neijing is integrated into people's daily life through timing tools, reminding people to keep healthy scientifically at any time and letting everyone know how to keep healthy with Huangdi Neijing.

Reference to the above content: Baidu Encyclopedia-Twelve o'clock