Chinese Star Chart: The 28 Lunar Mansions Explained

The Chinese sky is divided into 28 lunar mansions (宿), grouped into four symbols of seven mansions each. They mark the strip of sky the moon passes through in one month, so the system works like the Western zodiac — but it divides the same path into 28 stations rather than 12 signs, and it was built for calendars, timekeeping and navigation before it was ever used for fortune-telling.

The four symbols and their seven mansions

Read clockwise from the east and you have the whole system: 28 stations, four animals, four directions, four seasons. A chart that prints only the Chinese characters is beautiful and almost useless to a Western viewer; the ones that work in a shop print the character, the romanisation and the constellation it maps to.

Why 28, and not 12

The moon completes one circuit of the sky in about 27.3 days — the sidereal month. Divide that circuit by the number of days and you get a natural ruler: roughly one mansion per night. Stand outside on any evening, note which mansion the moon sits in, and you can tell what day of the month it is without a calendar. That is the original function, and it is why the mansions are of very uneven size — the divisions follow groups of stars that were easy to recognise, not an abstract geometry.

The Western zodiac solves the same problem differently, using the sun's path across twelve equal 30-degree segments (roughly 12 solar months). The Chinese system uses the moon's path across 28 unequal star groups (roughly 28 lunar nights). Both are calendars. Neither is more "correct" — they answer different questions.

What the mansions were used for

• Calendars and seasons. The four symbols are tied to the four seasons, so the position of a mansion told an agricultural society where it was in the year.
• Timekeeping. Along with the Big Dipper, which the charts place at the centre of the sky, the mansions served as a clock at night.
• Navigation. Sailors and travellers used the mansions and the Pole Star together to hold a bearing.
• Astrology and state ritual. Because the sky was read as a comment on the emperor's mandate, the mansions carried political meaning: an eclipse or a comet in a particular mansion was a message about the court.
• A parallel naming system. Each mansion can carry an associated animal and element in later astrological traditions, which is where the system most often gets confused with the twelve-animal zodiac.

How the system differs from the Chinese zodiac

This is the single most common mix-up, and it is worth stating plainly.

They coexist and they are unrelated. A person born in the Year of the Goat has no lunar mansion associated with their birth; the two systems answer different questions and were used by different specialists.

When the system appears in the record

The four symbols are attested on archaeological material from the Warring States period, and complete lists of the 28 mansions appear in Han-era texts — among them the Huainanzi, a compilation from the second century BCE, and the astronomical chapter of the Records of the Grand Historian. The system therefore predates the telescope by roughly two thousand years and was already old when it was written down. Those dates are the ones a chart should carry; a chart that presents the 28 mansions as an undated tradition is leaving out the most interesting part.

What to look for in a star chart

• The four symbols placed by direction, not as decoration. The dragon belongs to the east, and a chart that puts it anywhere else is a pattern rather than a map.
• The Big Dipper marked. It is the anchor of the northern sky and the key to finding the Pole Star.
• The 28 mansions in sequence, numbered or lettered, so the order is legible without prior knowledge.
• Romanisation alongside the characters. Without it, the chart is unreadable to the audience most likely to buy it.
• A note on the epoch. Star positions move with precession; a chart drawn for a historical epoch should say which.

Frequently asked questions

What are the 28 lunar mansions?

A division of the sky into 28 unequal stations along the moon's monthly path, grouped into four symbols of seven: the Azure Dragon in the east, the Black Tortoise in the north, the White Tiger in the west and the Vermilion Bird in the south. In order, starting from the east, the mansions are Jiao, Kang, Di, Fang, Xin, Wei, Ji, Dou, Niu, Nü, Xu, Wei, Shi, Bi, Kui, Lou, Wei, Mao, Bi, Zi, Shen, Jing, Gui, Liu, Xing, Zhang, Yi and Zhen.

Are the 28 mansions the same as the Chinese zodiac?

No. The zodiac is a 12-year cycle of animals applied to birth years. The 28 mansions divide the sky along the moon's path within a single month. They were used for calendars, timekeeping, navigation and state astrology; the zodiac is used for birth-year fortune. They are separate systems with separate specialists.

Why do the mansions have different sizes?

Because they were defined by groups of visible stars rather than by even geometry. A mansion's extent ran from one recognisable asterism to the next, so some cover a few degrees and others much more. The unevenness is a record of how the sky was actually observed, which is why the system remained practical for nearly two millennia.

What is the Black Tortoise?

The northern symbol (玄武), a tortoise entwined with a snake, associated with winter and with the seven northern mansions from Dou to Bi. In Chinese cosmology the four symbols correspond to the four cardinal directions; the tortoise takes the north, the dragon the east, the tiger the west and the bird the south.

Do Chinese star charts show constellations?

Not in the Western sense. The mansions are star groups used as measuring stations, and Chinese astronomy also recognised a large number of named asterisms with their own boundaries and lore — considerably more than the 88 modern constellations. A good chart shows the mansions and the major asterisms without pretending the two systems map onto each other.

Next: The Chinese dynasties in order covers the historical timeline, and The 64 hexagrams of the I Ching covers the third strand of Chinese reference material.

The chart described here is The Twenty-Eight Mansions Star Chart, printed in three sizes on 240gsm matte art paper. Trade tiers begin at 12 pieces — sign in for pricing.