Lidong occurs at celestial longitude 225°, around November 7-8. The astronomical start of winter in the traditional almanac. Water element strengthens; yin energy moves toward annual peak.
Tradition: "tonifying winter" (補冬) — eating warming foods like mutton stew, ginger duck. In northern China, dumplings are traditional. Climate: noticeable cold settles in.
The name Lidong (立冬 Lì Dōng) is attested in pre-Qin sources, and the Yuan-dynasty Collected Interpretations of the Seventy-Two Pentads (月令七十二候集解) glosses winter as an ending, the season in which the ten thousand things are gathered and stored. The emphasis falls on storage, not on cold. The Monthly Ordinances chapter of the Book of Rites describes the sovereign leading his ministers out to greet winter at the northern suburb. The Huainanzi treatise on celestial patterns (淮南子·天文訓) preserves the earliest surviving complete list of all twenty-four terms, Lidong among them, which shows the scheme was already fixed by the Western Han. Lidong belongs to the four beginnings alongside Lichun, Lixia and Liqiu; together with the two solstices and two equinoxes they form the eight nodes, the oldest layer of the whole system. In sequence it follows Shuangjiang and opens toward Xiaoxue, and the last eighteen days before it are traditionally assigned to earth, after which authority passes to Hai water. The winter-supplementing custom noted above rests on this same idea of storing.
In Bazi (八字 bā zì, Four Pillars) practice Lidong switches the month pillar, not the year pillar. The moment the term is crossed the month branch becomes Hai (亥). This makes births near Lidong unusually delicate: two people born on the same calendar day can fall into the Xu (戌) month and the Hai month respectively, which changes the month stem as well and can rewrite the whole structure of a chart. Practitioners therefore look up the exact crossing minute for that year and allow for the gap between the birthplace and the standard meridian.
Lidong is not the meteorological start of winter. Modern climatology waits for five consecutive days averaging below 10°C; by that yardstick most of China has not entered winter on the day of Lidong, and the far south may wait another month or two. A solar term marks the sun's position on the ecliptic, not a temperature threshold. For the same reason, the classical note that water begins to ice and the ground begins to freeze describes the Yellow River valley. Read literally in Guangdong or overseas, it simply makes the term look inaccurate.
Hai stores Ren (壬) water as its governing hidden stem and Jia (甲) wood as a residual one, with some lineages counting Wu (戊) earth as well. That gives the Hai month a duality easy to overlook: water is in command, yet Jia wood reaches its growth stage precisely here, so wood finds a root in deep winter. Hai also combines with Yin (寅) toward wood, clashes with Si (巳), and joins Zi and Chou to assemble the northern water direction. In the Hai–Mao–Wei wood trinity, Hai is where wood is generated. These relationships usually explain a chart better than the flat remark that winter water is strong.
The twelve waxing-and-waning hexagrams assign the Hai month to Kun (坤), six yin lines with no yang at all, and one traditional reading concludes that yang is wholly absent from Lidong onward. Another points out that Jia wood is hidden inside Hai and begins its growth phase there, so yang has already stirred underground and cannot be called absent. The two positions are not a contradiction to be resolved but a difference in vantage point: one describes what is visible above ground, the other what is latent within the branch.
The three pentads of Lidong are given as water beginning to ice, the ground beginning to freeze, and pheasants entering the great waters to become shen (蜃, large clams). The first two are direct observation; the third is inference. Pheasants vanish in winter, and the iridescent markings on coastal clam shells resembled their plumage, so a transformation was supposed. The value of such records is not zoological accuracy but the method they preserve: visible phenomena used as checkpoints against which a calendar could be verified.
In the traditional almanac, yes. Lidong is winter's official start, when the sun reaches 225° of celestial longitude, usually 7–8 November. In modern meteorology, no: winter is declared only after five consecutive days averaging below 10°C, a threshold much of China has not met on that date and southern China may not meet for another month. The two systems answer different questions, one about astronomical position and one about measured temperature.
Only the month pillar. Lidong is a sectional term and not a mid-term, so at the crossing moment the month branch turns from Xu (戌) to Hai (亥), and the month stem follows from the year stem by the standard rule. The year pillar does not change until the following Lichun. Anyone born on the day of Lidong needs the crossing time to the minute, or the month pillar may be set wrongly.
No, and the two are not fixed relative to each other. Lidong is defined by the sun's ecliptic longitude and lands on 7 or 8 November every year, while the first day of the tenth lunar month is defined by the new moon and drifts. Lidong usually falls between late in the ninth lunar month and the middle of the tenth. Calling the Hai period the tenth month refers to the solar-term month, not the lunar one, which is the most common source of confusion here.
The custom follows from the idea of winter as a season of storing: the harvest is in, outdoor labour pauses, and warm dishes mark the turn of the season. Ginger duck and mutton hotpot are common in Fujian and Taiwan, dumplings in northern China. This is a long-standing culinary tradition described here as cultural practice, not as dietary or medical advice.
Mainstream Ziwei Doushu (紫微斗數 zǐ wēi dǒu shù) sets the Life and Body palaces and the stars from the lunar month, day and hour, so Lidong does not enter the calculation. Solar terms belong to Bazi, where they fix the month pillar and the start of the luck cycles. A minority of lineages do define the month by solar term instead, a genuine divergence, so it is worth checking which convention a given chart tool follows.