Chinese astrology reads a birth year rather than a birth moment: which of the twelve animals that year falls under, and which of the five elements pairs with it on a repeating sixty year cycle. The animal is the familiar face of a much older calendrical system, the sexagenary cycle of ten Heavenly Stems and twelve Earthly Branches, and it shares its underlying cosmology of element, direction and change with the eight trigrams of the I Ching.

History

The sexagenary cycle, the pairing of ten Heavenly Stems with twelve Earthly Branches into sixty distinct combinations, is one of the oldest continuously used calendrical systems on record: Shang dynasty oracle bone inscriptions already use stem and branch pairs to name individual days, a practice going back to roughly 1250 BCE. The twelve Earthly Branches would later carry the animal names the system is now best known by, and the fullest early surviving statement of that animal list is a Han dynasty text, Wang Chong's Lunheng, from the first century CE, though the pairing itself may well be older than its first surviving written record.

The five elements, wood, fire, earth, metal and water, come from a separate but related correlative system, Wu Xing, systematised during the Han dynasty into a cycle in which each element generates the next and overcomes another, applied to seasons, directions, organs of the body and much else besides the calendar. Paired with the sexagenary cycle, each of the twelve animal years also carries one of the five elements and a yin or yang polarity, which is what turns a twelve year animal cycle into the full sixty year cycle popular astrology draws on: each element spans two consecutive years under the same animal, one yin and one yang, before the next element takes its turn.

The eight trigrams belong to an older and originally separate tradition, the I Ching, or Book of Changes, whose core layer is traditionally placed in the early Western Zhou dynasty, roughly the eleventh to eighth century BCE. Each trigram stands for a fundamental natural force, heaven, lake, fire, thunder, wind, water, mountain or earth, and each carries its own element and direction. A Chinese astrology reading commonly draws on this shared cosmology of element and direction as a further layer alongside the animal and element of the birth year itself.

The Twelve Animals

The twelve animals name the twelve Earthly Branches, and a birth year falls under exactly one of them in a fixed, repeating order.

• Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog and Pig, in order, are the twelve, and the cycle repeats every twelve years.

Each animal is held to carry its own temperament, and a reading names the animal a birth year falls in and what that pairing is traditionally held to emphasise, before layering in the element and polarity below.

The Five Elements And Yin And Yang

Wood, fire, earth, metal and water are the five phases of Wu Xing, read in two cycles: a generating cycle (wood feeds fire, fire makes ash and so earth, earth bears metal, metal collects water, water nourishes wood) and an overcoming cycle that runs a different order. Each birth year carries one of the five, which is what turns the bare twelve year animal cycle into the full sixty year cycle: with each element spanning two consecutive years under the same animal, one yin (receptive) and one yang (active), five elements times twelve animals gives the sixty distinct year combinations of the traditional calendar before it repeats.

• Wood, Fire, Earth, Metal and Water, the five, each paired in turn with every animal across the sixty year cycle.

The Eight Trigrams

The bagua, the eight trigrams of the I Ching, are a separate and older tradition that Chinese astrology shares its cosmology with rather than draws its animals from. Each trigram is a stack of three broken or unbroken lines standing for a fundamental natural force, and each carries its own element and compass direction, the same vocabulary of element and direction the animal years are read against.

• Qian (heaven), Dui (lake), Li (fire), Zhen (thunder), Xun (wind), Kan (water), Gen (mountain) and Kun (earth), the eight.

How A Reading Is Constructed

A reading starts from the birth year alone, converted to its place in the sixty year cycle to give one animal and one element, since the Chinese lunisolar new year does not fall on 1 January, a birth in January or February can belong to the animal year before the calendar year suggests. From the animal and element, the reading draws the traditional character and emphasis held to belong to that pairing, and folds in the shared element and direction cosmology of the eight trigrams as a further layer.

This report item reads at the birth year level, the accessible entry point into the system; a separate Ba Zi: The Four Pillars Of Destiny report item builds the fuller version of the same stem and branch mathematics, four pillars instead of one, for a birth year, month, day and hour together.

Where To Read More

• RatRat, first of the twelve.
• OxOx, second of the twelve.
• TigerTiger, third of the twelve.
• RabbitRabbit, fourth of the twelve.
• DragonDragon, fifth of the twelve, the only mythical animal in the cycle.
• SnakeSnake, sixth of the twelve.
• HorseHorse, seventh of the twelve.
• GoatGoat, eighth of the twelve.
• MonkeyMonkey, ninth of the twelve.
• RoosterRooster, tenth of the twelve.
• DogDog, eleventh of the twelve.
• PigPig, twelfth and last of the twelve.
• WoodWood, one of the five phases a birth year pairs with its animal.
• FireFire, one of the five phases.
• EarthEarth, one of the five phases.
• MetalMetal, one of the five phases.
• WaterWater, one of the five phases.
• QianQian, heaven.
• DuiDui, lake.
• LiLi, fire.
• ZhenZhen, thunder.
• XunXun, wind.
• KanKan, water.
• GenGen, mountain.
• KunKun, earth.
• JiaJia, the first of the ten Heavenly Stems the sexagenary cycle pairs with the twelve Earthly Branches.
• YiYi, the second Heavenly Stem.
• ZiWater BranchesZi, the first of the twelve Earthly Branches the animal Rat names.
• ChouEarth BranchesChou, the second Earthly Branch, named by the Ox.