Why did the ancients think the winter solstice was an auspicious day?

According to the ancient theory of yin and yang, the yin energy is at its strongest around the winter solstice. When it is the coldest, the yin energy almost reaches its peak, and the energy is pure yin. Because the height of the sun is the lowest in the year at this time, the sunshine is most southerly and the sunshine time is the shortest, so it is the coldest.

But the arrival of the coldest day also marks that the Yang Qi is about to be generated, and the weather will start to get warmer. As the saying goes, things must be reversed if they are not extreme. Therefore, the winter solstice is worth remembering because it is the time when the cold is extremely cold and it is also the beginning of spring.

Extended information

According to historical records, during the Zhou and Qin Dynasties, the winter solstice was the first month. It means the beginning of the new year. The ancients believed that the winter solstice is the beginning of the next cold and warm cycle and is an auspicious day. It is equally important as the "first day of the first lunar month" and is also called the "small year".

Celebrating the Winter Solstice as a festival began in the Han Dynasty, became popular in the Tang and Song Dynasties, and has been passed down to this day. We can also get a glimpse of the ancients' understanding and cultural interpretation of the winter solstice from some "winter solstice poems" written by poets (ci) of the Tang and Song Dynasties.