At what time of year did China's ancient times have a tradition of differential DCs

The custom of sticking willows was associated with avoiding epidemics. The Tang believed that wearing a willow branch on one's head during rituals by the river would rid one's head of poisonous insects. The Qingming Festival is the time when willows sprout and green, and there are folk customs of folding, wearing and inserting willows. When people step on the green hand folded a few branches of willow, can be held in the hands to play, can also be woven into a hat to wear on the head, can also be taken home inserted in the lintel, eaves.

The Qingming Festival has absorbed the content of another earlier festival, the Shangsi Festival. In ancient times, the festival was held on the third day of the third month of the lunar calendar, and the main customs were trekking in the green and purifying purification (bathing in the river to pray for blessings and eliminate calamities), reflecting the psychological needs of people who were in urgent need of spiritual adjustment after a dreary winter. Lu Ji of the Jin Dynasty wrote in a poem: "Late late spring, the weather is soft and favorable. Yuan Ji Long early Si, Maundy tour of the Yellow River." That is, people in the Festival of Purification of Purification, trekking vividly portrayed.