As early as 2,500 years ago, around the Spring and Autumn Period (770-476 BC), Chinese people determined the winter solstice by observing movements of the sun with sundials. It falls on December 22 or 23.
In the Chinese idea of Yin and Yang, Yin symbolizes feminine, negative and dark qualities of the universe, and yang masculine, positive and fiery qualities, and when something goes to one extreme it then goes to the opposite. Winter solstice in the northern hemisphere is the shortest day and longest night. After it, days become longer, which ancient Chinese thought meant yang qualities would become stronger, so should be celebrated.
The winter solstice became a festival during the Han Dynasty (206 BC-AD 220) and thrived in the Tang and Song dynasties (618-1279). Han officials organized celebrations and it was recognized as a holiday; frontier fortresses closed and business and travel stopped. In the Tang and Song dynasties, it was a day to make offerings to heaven and people＊s ancestors, something both emperors and common people did. According to records from the Qing Dynasty (1644-1911), the day was regarded to be as important as Spring Festival (Chinese Lunar New Year).
Though Winter Solstice Festival used to be considered the second most important festival after Spring Festival, its importance has decreased with urbanization and growing interest in Western festivals
