The winter solstice is the shortest day and longest night of the year in the Northern Hemisphere, and it is also the day when the yin and yang energies transition. From then on, the yin and yang energies become extremely strong and weak, and the yang energy begins to sprout. The activity of life will slowly turn from decline to prosperity and from stillness to stillness. Therefore, the winter solstice is also known as "one yang born", and there is also a folk saying "one yang born on the winter solstice".

At the winter solstice, "counting nine cold days" begins, which is commonly known as "entering nine.". Since ancient times, there has been a custom of "counting nine" in Chinese folk culture, also known as "winter nine nine" or "jiao nine". Starting from the winter solstice, every nine days counts as one "nine", and the number of "nine" is 81 days, commonly known as "consecutive winter nine". After the nine peach blossoms bloom, the cold winter is almost over and the warm spring is about to come.

Regarding the concept of "counting nine", many different versions of "Nine Songs", "Counting Nine Songs", "Nine Cold Elimination Songs", and "Cold Elimination Map" have been passed down from ancient times to the present day. Among them, the well-known "Counting Nine Songs" are: In 1929, no action was taken; in 3949, walking on the ice; in 5969, watching the willows along the river; in 799, the river opened; in 899, geese came; in 999, one and nine, oxen walked everywhere.

In addition to "counting nine", there are also people who take nine characters with nine strokes to form a sentence, and draw them in red every day. After drawing nine characters, it is the day when spring returns after the cold is over. Common sentences include "Cherish the weeping willows in front of the pavilion and wait for the spring breeze (wind)".

On the winter solstice, people have special dietary customs. In the past, it was emphasized that the winter solstice is as big as the new year, while also praying for health, happiness, and auspiciousness.