The Twenty-Eight Lunar Mansions (Er Shi Ba Xiu)
In a Nutshell
Twenty-eight groupings of fixed stars along the ecliptic, rotating in turn with the Seven Luminaries.
Quick facts
| Item | Detail |
|---|---|
| Belongs to | The ancient system of astronomy and calendrical science |
| Composition | Twenty-eight groupings of fixed stars along the ecliptic and celestial equator |
| Four Symbols | Azure Dragon of the East, Black Tortoise of the North, White Tiger of the West, Vermilion Bird of the South |
| Calendrical use | Paired with the Seven Luminaries; each day one mansion takes its turn, called the "duty mansion" |
What are the Twenty-Eight Lunar Mansions?
The Twenty-Eight Lunar Mansions are an ancient system for dividing the sky into groupings of fixed stars — twenty-eight star groups along the ecliptic and the celestial equator. Observing the backdrop of stars against which the sun and moon travel, the ancients divided the full circuit of heaven into twenty-eight regions, each named for its most prominent star group — Jiao, Kang, Di, Fang, and so on. This system was one of the foundations of ancient astronomy and calendrical science.
The mansions are arranged by direction into four groups of seven: the Azure Dragon of the East — Jiao, Kang, Di, Fang, Xin, Wei, Ji; the Black Tortoise of the North — Dou, Niu, Nu, Xu, Wei, Shi, Bi; the White Tiger of the West — Kui, Lou, Wei, Mao, Bi, Zi, Shen; the Vermilion Bird of the South — Jing, Gui, Liu, Xing, Zhang, Yi, Zhen. The Four Symbols were matched to the four seasons and the Five Elements — the ancients' way of mirroring earthly order in the starry sky.
In calendrical use, the mansions are paired with the Seven Luminaries — the Sun, Moon, Mars, Mercury, Jupiter, Venus, and Saturn — with one mansion taking its turn each day, called the duty mansion. The mansions advance one per day in order, cycling endlessly. Traditional almanacs print the day's duty mansion beneath each date, a practice that continues to this day and is one of the common notations in the Chinese almanac.
The Twenty-Eight Mansions are at root a coordinate-like division of the sky, used by the ancients to record the positions of the sun and moon; later generations attached many elaborations to it. When studying it, keep calendrical astronomy separate from later accretions — the two should not be confused. This page introduces it only as traditional almanac culture, to help readers understand the concept, and serves as the basis for no judgments about practical matters.
Classical sources
"The twenty-eight mansions govern the twelve provinces."
(Rendered from the classical Chinese original.)
Source: *Shi Ji* (Records of the Grand Historian), *Tian Guan Shu* (Treatise on the Celestial Offices)
Plain-language reading: The ancients matched the twenty-eight mansions to the twelve provinces of the human world, reflecting the astronomical idea of dividing territory by the stars. Note: the original here uses the character "She" — the form this chapter of the *Shi Ji* habitually uses for "mansions."
*For entertainment purposes only.*