Grand ceremony
Ancient people used divination to predict the temperature in winter. They believed that if it is crystal clear on lidong, there would be a cold winter; a cloudy lidong would herald a mild winter. Start of Winter announces officially that everything has entered a state of recuperation and collection. The entire period of lidong, which spans 15 days, is divided into three minor phases. Through observation ancient people discovered interesting bits of nature corresponding to each phase.
During the first five days of the solar term, water begins to freeze; during the second phase, the ground begins to freeze. The combination of ice and water always makes for an interesting twist. Frozen soil is an attraction during this period. China's permafrost area is about 2.1 million square kilometers, nearly 90 percent of which is located on the Qinghai-Tibet Plateau.
During the third phase, the saying goes, "pheasants transform into large clams". In the old days, people saw fewer pheasants at that time of the year, but large clams with similar color stripes showed up by the seaside, so they assumed that pheasants had turned into clams after lidong. They also believed that a mirage was formed by clams exhaling cool air.