What does the great cold mean?

Twenty-nine means "twenty-nine" in the lunar calendar, and twenty here means twenty. The Great Cold, the last of the 24 solar terms, is the 29th of the twelfth lunar month.

The twenty-four solar terms are divided according to the position of the sun on the ecliptic, which reflects the changing law of the atmosphere. Everything grows in the atmosphere on the earth's surface and changes with the climate, with spring growing and summer growing, autumn harvesting and winter storage, and four seasons circulating. The change of the atmosphere is the change of the five elements, which reflects the change of the earth's surface climate.

The great cold solar term is located in the middle of ugly month, starting from the slight cold solar term and ending before beginning of spring. This period of time is the time when winter and spring alternate, that is, when winter water hides spring wood. Therefore, the slight cold solar term is the beginning of the hiding of water and the appearance of wood gas in winter, and there is a hidden and obvious relationship between them until the end of beginning of spring.

Before beginning of spring, it was the last day of ugly month, the last day of winter, and winter was water. Therefore, beginning of spring was short of water the day before, which shows that the water in winter is completely hidden and the wood is completely exposed. Wood gas replaced winter water, and the season entered spring. Then the great cold solar term is located in the middle of the ugly month, that is, when the winter water is Shimada Hanzo and the wood is half exposed.

Therefore, the winter water in the great cold solar terms is almost equal to Chunmu. Before the great cold, emerging winter water was stronger than spring wood, and after the great cold, emerging wood was stronger than winter water. Water is old yin, representing the cold in winter, and wood is shaoyang, representing the warmth in spring. As the saying goes, "After extreme cold, the weather will get warmer in the future", because after extreme cold, wood gas is stronger than winter water.