Ancient Huangdi calculated solar terms.

This calendar should be called China Lunar calendar. The China lunar calendar is the most scientific calendar in the world at present, and its essence is neither a pure lunar calendar nor a pure solar calendar, but a combined calendar of yin and yang. Simply put, the lunar calendar is a calendar in which the moon changes periodically, and the solar calendar is a calendar in which the sun changes according to the period of revolution of the Earth. Generally speaking, the Chinese lunar calendar adopts the method of 19 to set 7 leap, which successfully takes into account the visual cycle of the sun and the moon, so it is a yin-yang calendar. At present, the only official calendar in the world that has been formulated and implemented for a long time is the lunar calendar in China. The formation of China's lunar calendar is taichu calendar in the Western Han Dynasty, which originated from the Zhuan Xu calendar used in the Qin Dynasty. The lunar calendar of China in later generations has been improved many times, mainly about the setting of inserting related solar terms in leap months, but the basic idea has not changed.

The first month of the lunar calendar is usually around beginning of spring. Modern beginning of spring Day is the day when the sun reaches the longitude of 3 15 degrees, but the phases of this day are different every year, so the interval between the first day of the first lunar month and beginning of spring Day is not fixed.

In addition, Huangdi Neijing is a medical work, but due to the unique thinking characteristics of China ancient medicine, it also records a lot of astronomical and phenological characteristics, and other chapters also involve some clinical psychological summaries and views on ancient You Zhu. However, the question of "how did mankind come, the thinking of all mankind, etc." It is not involved, and the so-called "mystery of meridians" is just a misunderstanding of the world. The main authors of this book are China ancient medical workers and enthusiasts from the late Zhou Dynasty to the Western Han Dynasty, and also compiled some works in the Sui and Tang Dynasties. Finally, knowing that this book is as hard as being a migrant worker is true.