The Four Symbols of Chinese Astronomy (Sìxiàng)

The Four Symbols of the Chinese Sky

Dragon, Bird, Tiger, Tortoise

To a Chinese astronomer of the Han dynasty, the first star to rise on a spring evening was not Spica, as we call it, but the horn of a great dragon, with the rest of its giant body emerging as night progressed. Over the next few hours, the dragon’s neck would follow, then its body, then its heart (the red star we call Antares), and finally its long tail, curving up out of the southern horizon. By the time the dragon had fully risen, the entire creature would cover nearly a quarter of the night sky, spanning seven separate star groups that Western astronomy calls Virgo, Libra, Scorpius, and Sagittarius.

This is the logic of the four symbols of Chinese astronomy, sìxiàng (四象), a system that makes the Greek tradition of dozens of separate constellations look almost piecemeal by comparison.

What the Four Symbols Are

Chinese astronomy divides the equatorial band of the sky (the band the Moon and planets travel through) into 28 uneven segments defined by the stars within. Each segment is called a mansion. The four symbols group the 28 mansions into four sets of seven, with each set anchored to a cardinal direction, a season, a color, and one of the Five Phases.

Each symbol is a mythological creature whose body is mapped onto the seven mansions of its quadrant. Together, the four symbols organize roughly half of the visible sky. The other half, the circumpolar region around the celestial pole, is organized as the three enclosures, mirroring life on Earth in the domain of the emperor.

The fifth direction in Chinese cosmology is the center of the circle, associated with earth, yellow, and the Yellow Dragon. The center corresponds to the polar enclosures, not to a fifth symbol of the equatorial band. The four symbols are the wheel, with the center as the hub.

The Azure Dragon (青龍)

The Azure Dragon is the easiest to visualize, and the one that carried the most political weight. The dragon was a symbol of the emperor, the largest and most important of the four.

Here is the dragon, mansion by mansion, from west to east:

• Horn (角 Jiǎo, mansion 1): anchored at Spica (α Virginis). The dragon’s horns rise first.
• Neck (亢 Kàng, mansion 2): stars in northern Virgo, connecting horns to body.
• Root (氐 Dī, mansion 3): stars in Libra. The dragon’s foundations, the base of the body.
• Room (房 Fáng, mansion 4): stars in Scorpius, around π Scorpii. The body cavity.
• Heart (心 Xīn, mansion 5): anchored near Antares (α Scorpii). The brightest star of the dragon, glowing red at the very center of the creature.
• Tail (尾 Wěi, mansion 6): the long curving line of stars that Western astronomy reads as Scorpius’s stinger. Here it is the dragon’s tail, sweeping behind the body.
• Winnowing Basket (箕 Jī, mansion 7): stars in Sagittarius. The dragon’s foot, or in some readings the basket the dragon shakes to scatter the wind.

The body is contiguous. If you trace the seven mansions in order, you are tracing an actual creature laid out across the sky from horns to tail. Antares, that fierce red star at the center, is the dragon’s heart.

In modern Western terms, the dragon’s body crosses Virgo, Libra, Scorpius, and the head of Sagittarius. Where Greek astronomy saw four separate constellations with four separate myths, Chinese astronomy saw one body.

The White Tiger (白虎)

The White Tiger rules the autumn sky in the west. Its anatomy is partly mapped, partly suggested.

• Legs (奎 Kuí, mansion 15): stars in Andromeda.
• Bond (婁 Lóu, mansion 16): stars in Aries.
• Stomach (胃 Wèi, mansion 17): more stars in Aries.
• Hairy Head (昴 Mǎo, mansion 18): the Pleiades. The bristling fur of the tiger, in the most evocative traditional reading.
• Net (畢 Bì, mansion 19): the Hyades and Aldebaran. A hunting net, or the tiger’s open mouth, depending on the source.
• Beak (觜 Zī, mansion 20): the head of Orion. The smallest mansion of all twenty-eight, only about two degrees across.
• Three Stars (參 Shēn, mansion 21): Orion’s belt and the bright stars around it.

The Vermilion Bird (朱雀)

The Vermilion Bird rules the summer sky in the south. A word about translation first: the bird is sometimes called the phoenix in English, but this is loose. The Chinese phoenix, the fenghuang, is a separate mythological creature, and the Vermilion Bird is something else, more specifically the red bird of the south, associated with fire and yang energy. “Vermilion Bird” or “Red Bird” is the accurate name.

• Well (井 Jǐng, mansion 22): stars in Gemini.
• Ghost (鬼 Guǐ, mansion 23): stars in Cancer, including the Beehive Cluster (M44).
• Willow (柳 Liǔ, mansion 24): the head of Hydra.
• Star (星 Xīng, mansion 25): Alphard, the lone bright star of Hydra.
• Extended Net (張 Zhāng, mansion 26): the middle of Hydra.
• Wings (翼 Yì, mansion 27): stars in Crater.
• Chariot (軫 Zhěn, mansion 28): stars in Corvus.

The Bird’s anatomy is the most abstract of the four. The mansion names (Well, Ghost, Willow, Star, Net, Wings, Chariot) do not directly read as a bird’s body. Only Wings is clearly avian. The other names are objects or features that belong to the bird’s territory rather than to its anatomy. The Vermilion Bird is less a body laid out across the sky than a presiding presence over the southern summer quadrant.

Not every quadrant of the Chinese sky is as well mapped as the others. The Dragon got the most fully realized body, presumably because of its imperial association. The Bird and Tortoise got cosmological roles more than anatomical maps.

The Black Tortoise (玄武)

The Black Tortoise rules the winter sky in the north, and it is the strangest of the four symbols. The Black Tortoise is not actually a tortoise. It is a tortoise entwined with a snake, the two creatures joined together in a single image.

This dual-creature pairing is among the most visually striking figures in Chinese cosmology. The tortoise is hard, slow, ancient, the embodiment of stability and longevity, a creature whose shell was historically used for divination. The snake is fluid, fast, vital, the embodiment of change and energy. Together they are joined opposites at the cold dark pole of the year, a yin-yang image cast onto the sky. The Black Tortoise is the cosmic ancestor, the watcher in the deep north.

• Dipper (斗 Dǒu, mansion 8): stars in Sagittarius. Note: this is the Southern Dipper, not the Big Dipper of Ursa Major.
• Ox (牛 Niú, mansion 9): stars in Capricornus.
• Girl (女 Nǚ, mansion 10): stars in Aquarius.
• Emptiness (虛 Xū, mansion 11): more stars in Aquarius.
• Rooftop (危 Wēi, mansion 12): stars in Aquarius and Pegasus.
• Encampment (室 Shì, mansion 13): stars in Pegasus, including Markab.
• Wall (壁 Bì, mansion 14): stars in Pegasus and Andromeda, including Algenib.

The mansion names (Dipper, Ox, Girl, Emptiness, Rooftop, Encampment, Wall) read almost like the inventory of a winter settlement. There is no anatomical mapping at all. The Black Tortoise does not lie across these mansions as a body. The Tortoise presides over them as a guardian, watching from the still cold pole of the sky.

What the Four Symbols Are Not

A common point of confusion: the four symbols are not the Chinese zodiac. The Chinese zodiac is the twelve-animal cycle (rat, ox, tiger, rabbit, dragon, snake, horse, goat, monkey, rooster, dog, pig), and it is a twelve-year cycle tied to Jupiter’s orbit and the system of earthly branches. It is a calendar and divination system, not a sky-mapping system.

The four symbols, by contrast, are a sky-mapping system. They organize space (cardinal directions) and seasons (the rotation of the night sky through the year). The Dragon appears in both systems, which is the source of much of the confusion, but the imperial Azure Dragon of the sky is a different cultural figure from the Dragon of the twelve-year cycle.

The Seasonal Cycle

The rotation of the four animals is the function of the whole system. Each symbol has its season, and the sky reveals which season you are in.

At sunset in spring, the Azure Dragon dominates the eastern sky, rising as the Sun sets. By midnight, the dragon is overhead. At sunset in summer, the Vermilion Bird is high in the south, and the Dragon has already moved west. At sunset in autumn, the White Tiger is rising in the east, and the Dragon is setting. At sunset in winter, the Black Tortoise dominates the night, and the Tiger has rotated to the west.

The sky is a calendar. The four symbols rotate through the year like a wheel, each having its season of prominence. For a farmer planning planting, a fisherman planning his catch, or a court astronomer preparing the imperial calendar, this was vital information.

A Tradition Still Alive

Western readers sometimes encounter Chinese astronomy and wonder how it is used today.

Temple complexes are oriented to the four directions, with the appropriate symbol guarding each gate. Tang and Song dynasty tomb paintings show the four symbols on the four walls. The bronze mirrors of the Han dynasty often have the four symbols arranged around the rim. The symbols appear in feng shui, in traditional martial arts forms, and as design motifs in contemporary East Asian fantasy fiction, anime, and video games.

In Japan, the four symbols are called Shijin (四神): Genbu (the Black Tortoise), Suzaku (the Vermilion Bird), Byakko (the White Tiger), and Seiryu (the Azure Dragon). They are central to Shinto and Buddhist iconography and to the traditional orientation of Japanese cities (Kyoto was laid out with the four symbols guarding its four directions). In Korea, similar versions exist as the Sa-shin, and Goguryeo-era tomb murals show them in detail.