"Twenty-four solar terms" is the product of ancient farming civilization, and farming production is closely related to the rhythm of nature. It is a knowledge system formed by ancient ancestors following the farming season, observing the movement of celestial bodies and understanding the changing laws of seasons, climate and phenology throughout the year.
Initially determined by the bucket handle rotation direction of the Big Dipper, the Big Dipper rotates circularly, which is closely related to the 24 solar terms. China is located in the northern hemisphere, and the Tropic of Cancer runs through our territory.
The Tropic of Cancer is a special latitude with astronomical significance. With the seasonal changes in the Japanese sense, the phenology and climate of the Tropic of Cancer (Cape Yellow Cross) and its surrounding areas are also changing gradually. In ancient astronomy, bucket handle, the Big Dipper, was called the "sword", and bucket handle, the Big Dipper, was used as the standard to determine the month, and was called the sword fighting (also known as the "moon sword").