The Chinese Almanac

Open a traditional Chinese almanac — the Huangli or Tong Shu that families have kept for centuries — and every day carries a small block of notes: a lunar mansion, a day officer, a god of the Yellow or Black Path, the animal the day clashes with. Together they were used to pick good days for weddings, moves, openings and journeys. This guide explains what each entry means and how Fate Hall calculates them.

Four cycles running side by side

The almanac does not use one system but several cycles that turn at different speeds:

• The 28 lunar mansions repeat every 28 days, exactly four weeks, so each mansion always falls on the same weekday.
• The twelve day officers follow the day's earthly branch, counted from the branch of the solar month.
• The twelve day gods of the Yellow and Black Paths also follow the day branch, but start from a different point in each solar month.
• Clash and sha come straight from the day branch.

Because the officers and day gods depend on the solar month, the almanac uses the solar terms, not the lunar calendar, to decide where each month begins — the same months as a BaZi chart.

The 28 lunar mansions (二十八宿)

Long before the zodiac reached China, astronomers divided the sky along the Moon's path into 28 "lodges", seven in each of four quarters guarded by the Azure Dragon, Black Tortoise, White Tiger and Vermilion Bird. In the almanac each day is assigned one mansion in an unbroken sequence. Each mansion carries one of the seven luminaries and an animal — Jiao is 角木蛟, "Horn, Jupiter, flood dragon" — and the seven luminaries line up with the days of the week, so Jiao always falls on a Thursday.

Fate Hall counts the mansions continuously from the Julian day number, so the sequence never skips. Tradition sorts them into favourable and unfavourable days for big undertakings:

The twelve day officers (建除十二神)

The day officers are the almanac's most practical entry. Each solar month starts its count on the day whose branch matches the month: in the Tiger month (from the Beginning of Spring) a Tiger day is "Establish", the next day "Remove", and so on through all twelve. One detail follows from this: on the day a new solar month begins, the officer repeats the previous day's name, which is why almanacs show two "Establish" days, or two "Full" days, in a row around each solar term.

An old rhyme sums up their reputation: "Establish, Full, Balance and Receive are black; Remove, Danger, Stable and Hold are yellow; Success and Open are usable for anything; Close and Destruction are not." Fate Hall follows that rhyme for its Yellow and Black marks.

Yellow Path and Black Path days

A second set of twelve, the day gods, decides whether a day is on the Yellow Path (黃道), traditionally an auspicious day, or the Black Path (黑道). Six are yellow — Green Dragon, Bright Hall, Golden Coffer, Heavenly Virtue, Jade Hall and Life Controller — and six are black. The sequence always runs in the same order; what changes from month to month is where the Green Dragon starts.

"Choosing a Yellow Path day" (黃道吉日) became a common phrase for picking an auspicious date, long after most people stopped following the rest of the almanac.

Clash and sha

Every day branch clashes with the branch opposite it on the circle of twelve, so each day "clashes" with one animal sign. Almanacs print it so that people born in that year can avoid starting important things on that day. The sha (煞) is an unlucky direction for the day, set by the day branch's three-harmony group; traditionally you would not travel or face that way for important business.

How Fate Hall scores a day

Fate Hall turns the entries into a simple score: 45 points to start, plus 15 when the day officer is yellow, 20 when the day god is on the Yellow Path and 10 when the mansion is favourable, minus 10 on a Destruction day. Days of 75 or more are listed as good days. Traditional date selection weighs many more symbolic stars, and serious practitioners check each person's own chart as well; treat the score as a quick summary of the four main entries, not a full almanac reading.

Solar months are dated in Korea Standard Time. Very occasionally, when a solar term falls just after midnight in Korea, a Chinese almanac printed for Beijing time will show that month change one day earlier. Fate Hall's almanac calculations have been checked against an independent almanac implementation for every day from 1950 to 2049: the mansions, clashes and sha directions match on all 36,525 days, and the officers and day gods differ only on those time-zone boundary days.

Common questions

Do I need to enter my birth date? No. The almanac is the same for everyone. If you have entered your birth date, Fate Hall adds a note when the day clashes with your own animal sign or Day branch.

Why does my printed almanac show a different "good for" list? Full almanacs combine dozens of symbolic stars to produce their lists of activities, and editions differ. Fate Hall shows the traditional meaning of the day officer, which is the core of those lists, rather than reproducing any one publisher's tables.

Is this the same as the Korean "son eomneun nal" (days without spirits)? No. Those are a separate Korean folk tradition based on the lunar day number. The entries here come from the Chinese almanac tradition shared across East Asia.

Related guides

• The Twelve Earthly BranchesThe twelve branches from Zi (Rat) to Hai (Pig): their element, solar month, double hour and hidden stems, and the harmonies and clashes between them.
• True Solar TimeWhy BaZi uses the Sun's position instead of clock time: longitude correction, the equation of time and daylight saving, with tables for major cities and every month.
• Clashes and CombinationsHow the twelve branches combine and clash: the Three Harmonies, Six Harmonies, clashes and the Korean Yuan Jin, with a full lookup grid and the punishments and harms of classical texts.
• Plum Blossom NumerologyShao Yong’s Plum Blossom method: Early Heaven numbers, casting by time or by numbers, the primary, nuclear and changed hexagrams, and reading the body and use trigrams — with the classic worked example.