The 28 lunar mansions (二十八宿) of classical Chinese astronomy — foundational reference for Tong Shu (通書) date selection, BaZi shen sha derivation, and the Four Symbols (四象) of the night sky. 28 mansions across 4 quadrants × 7 mansions each, with classical animal totems, elements, weekdays, and Tong Shu activity registers per mansion.
The 28 Lunar Mansions reference
This is the master directory for the 28 Lunar Mansions (二十八宿) reference. The 28 mansions are the foundational segmentation of the classical Chinese night sky — each mansion representing a specific arc along the celestial equator and carrying its own animal totem, element, weekday, and classical activity register. The mansions cycle through the calendar in a fixed seven-day rhythm, so each calendar date carries one mansion as its presiding register, used in classical Tong Shu (通書) date selection.
Voice constraint: these pages name each mansion and describe its classical register; they do not teach the procedure for determining which mansion governs a given calendar date, the day’s stem-branch pillar, or the integration of mansion + chart that determines whether a date is genuinely auspicious for a specific person. For chart-aware date selection, book the auspicious date selection consultation; for pre-computed dates by occasion, see the auspicious dates by month index.
Why the lunar mansion alone is not enough
The lunar mansion governing a candidate date is one signal in a complete date-selection reading — not the whole answer. Classical Tong Shu (通書) doctrine layers four inputs into any date selection.
The lunar mansion governing the date. The 28 Mansions cycle through the calendar in a fixed seven-day weekday-coupled rhythm, so each candidate date carries one mansion as its presiding register. This is the input these reference pages describe.
The day’s stem-branch pillar. Every calendar date is also a 60-jiazi day pillar — one of the 60 stem-branch combinations that cycle every 60 days. The day pillar carries its own register, classical activity associations, and clash-or-combination relationships with the chart of whoever the date is for.
The year and month context. The current Tai Sui (太歲, the year god), the month branch, and the running shen sha for the year all modulate the date’s register. A mansion classically auspicious for marriage may be partially neutralised if the date falls in a month that clashes with the bride’s zodiac.
The chart-specific question. The date is being selected for a specific person and a specific event. The combination of mansion + day pillar + year/month context + the person’s own BaZi chart determines whether the date is genuinely auspicious for them. The same date can be excellent for one person and contradicted for another.
This page describes the first input — the mansion's register. The reading is a useful starting reference. It is not a substitute for a chart-aware date selection that layers in the other three. Master Sean Chan’s auspicious date selection reads all four layers against your specific event question.
How the 28 mansions relate to other classical references
BaZi solar terms (24 節氣): the lunar mansions cycle independently of the solar terms, but both are read together in date selection. See the 24 Solar Terms reference.
BaZi shen sha (神煞): several BaZi auxiliary stars are derived from lunar-mansion positions. The mansion data is foundational to those derivations.
Auspicious dates by month: pre-computed favourable dates by occasion type (wedding, ROM, business opening, etc.) layer the mansion register together with the day’s stem-branch pillar and shen sha. See the index.
Chart-specific date selection: for events that warrant a date matched to your specific BaZi chart, book a date selection consultation.
Frequently asked questions
What are the 28 Lunar Mansions in Chinese astronomy?
The 28 Lunar Mansions (二十八宿) are the foundational segmentation of the classical Chinese night sky — 28 specific arcs along the celestial equator, each carrying a classical name, animal totem (the 二十八禽), element classification, and weekday association. The mansions are organised into 4 directional groups of 7 each, called the Four Symbols (四象): the Azure Dragon (east, spring), the Black Tortoise (north, winter), the White Tiger (west, autumn), and the Vermilion Bird (south, summer). The mansions cycle through the calendar in a fixed seven-day rhythm and are used in classical Tong Shu (通書) date selection.
How do the 28 Mansions relate to the Western zodiac?
The 28 Mansions are not analogous to the 12-sign Western zodiac — they are a different segmentation of the night sky entirely. Where Western astrology divides the ecliptic into 12 equal 30-degree arcs (the zodiac signs), Chinese astronomy divides the celestial equator into 28 unequal arcs (the mansions). Some mansions span 30+ degrees of right ascension; others as little as 1–2 degrees (the 觜 Zī mansion is famously narrow). The Four Symbols (四象) provide a 4-fold seasonal grouping but are not equivalent to the four cardinal zodiac signs.
How is the 28-mansion cycle used in date selection?
In Tong Shu doctrine, each calendar date carries one mansion as its presiding register. The mansion modulates the activity register of the date — some mansions are classically auspicious for marriages, others for business openings, others cautious for funerals or specific work. The 28-mansion cycle pairs with the 60-jiazi day-pillar cycle, the 12 Earthly Branch zodiac cycle, and the running shen sha for the year and month to produce the full date-selection calculus. The mansion is one of four major inputs; chart-specific application also requires the day pillar, the year/month context, and the BaZi chart of whoever the date is for.
Are the activity registers in this reference prescriptive?
No — descriptive. The classical Tong Shu activity registers per mansion (e.g., "Jiǎo days favourable for inaugurations and marriages") describe the mansion’s classical register in the absence of other modifying factors. Whether a Jiǎo day is genuinely auspicious for your specific marriage depends on the day’s stem-branch pillar, the month, the year, and your own and your partner’s BaZi charts. Use the reference to recognise classical doctrine; use a consultation for actually selecting a date.
AUSPICIOUS DATE SELECTION
Get a chart-aware auspicious date for your specific event.
Master Sean Chan’s date selection service reads your specific event against your own BaZi chart, the year and month context, the lunar mansion governing each candidate date, and the shen sha that activate. Zero generic almanac advice — every date is chart-specific.
A BaZi consultation reads your full four-pillar chart and identifies the shen sha that activate around career, relationship, and event-specific questions — the chart-side context that makes any date selection actually meaningful.
For pre-computed auspicious dates by occasion type and month — weddings, ROM, business openings, contract signing, moving house, renovation — see the master index of auspicious dates by month.