Lìdōng

Lidong, the Start of Winter, is the nineteenth solar term, at the sun's longitude of 225 degrees, around the seventh of November. It is a sectional (jie) term and marks the astronomical beginning of winter. The harvest is stored, the fields lie fallow, and the year turns inward toward rest. In the farming almanac it signals the season of conservation, and its customs centre on nourishment against the cold, in the north the eating of dumplings, and more widely the winter practice of building up the body with warming, tonic foods. Being a solar marker, it falls near the same Gregorian date each year. These are the observances of the East Asian agricultural tradition, resting on the twenty-four-fold division of the tropical year into equal solar arcs anchored to the sun's position.

Lidong, the Start of Winter, falls at 225 degrees, around 7 or 8 November, and is a jie, or sectional, term, opening the fourth and last of the traditional calendar's four seasons. As with the start of the other three seasons, Lidong's astronomical date does not correspond to when winter conditions actually arrive across China's varied climate. The term carries one of the solar calendar's more widely kept folk customs: in northern China it is traditionally marked by eating jiaozi, dumplings, said in one popular explanation to be shaped like ancient Chinese ingots or to resemble ears, tied to a folk story about the physician Zhang Zhongjing distributing warming dumpling-like medicine to treat frostbitten ears among the poor.

The twenty-four solar terms divide the ecliptic into equal arcs of fifteen degrees, and this one falls at 225 degrees of the sun's apparent longitude. It is a sectional term, a jie, one of the twelve that fall in the odd positions of the twenty-four and open the twelve solar months. The sectional terms and the major terms alternate strictly around the year, so a jie is always followed by a zhong fifteen degrees later.

The twelve major terms are what make the Chinese calendar work as a lunisolar one. Each ordinary lunar month is expected to contain exactly one major term, and the month takes its number from the term it contains, so the eleventh month is by definition the one holding the winter solstice. When a lunar month falls entirely between two major terms and contains none, it is declared intercalary and repeats the number of the month before it, which is how a thirteenth month is inserted without any fixed rule about when.

Lidong opens the winter at 225 degrees, the last of the four season-opening terms. In several regions it carries its own food customs, and in northern China it is associated with the eating of dumplings, though the observances attached to the individual terms vary a great deal by place and the atlas does not present any single set as standard.