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BaZi · 地支 亥

The Hai Branch (亥) — Pig, Water

Hai is the last branch and the first month of winter — the point at which the cycle has completed its work and turns inward to rest. It hides 壬 and 甲: Yang water as the main voice and Yang wood as its middle qi, which makes Hai a resting position that still contains the seed of the next spring.

The Hai branch — Pig line art
Branch
Hai 亥
Animal
Pig
Element
Water 水
Polarity
Yin
Hours
21:00–23:00
Season
early winter
Direction
north-west
Body
kidneys, bladder and the head
Classical image — the first freeze on a river that is still moving underneath

What the 亥 branch is

亥藏壬、甲. Ren is Yang water — the great river, carrying force without effort. Jia is Yang wood, the tree, stored inside. Water generates wood, so Hai's structure is generative even though the season is one of contraction. This is the branch's central paradox and the reason classical texts treat Hai as a fertile branch rather than a barren one: the year is over, and the next one is already in the ground.

Because Hai closes the cycle, it is the branch of the long view. Charts with prominent Hai tend to describe people for whom a decade is a reasonable unit of planning — not because they are patient by temperament, but because they genuinely experience time that way and are puzzled by people who do not.

Hai also carries the branch's well-known pairing with Yin (the Tiger branch): 寅亥六合, the six-harmony combination of early spring and early winter. Wood and water in harmony is the system's clearest image of support — one gives, the other receives — which is why charts with the pair often describe unusually effective long-term collaborations.

From the inside

From the inside, Hai feels like living at one remove from the pace of the people around you. You are aware of the longer arc: what this year is for, what the project is really building, what the relationship is actually becoming. That perspective is genuinely useful and it is genuinely isolating, because most conversations happen at a shorter timescale than the one you find interesting. You also tend to be more private about your own plans than your openness in conversation would suggest — the water is moving, but very little of it is on the surface.

Hidden stems in Hai

Hidden stemElementEnglishPolarityRank
RenWaterYangmain qi
JiaWoodYangmiddle qi

亥藏壬、甲. Ren (Yang Water) is the branch's own voice — force that does not need to be visible. Jia (Yang Wood) is the middle qi and the reason Hai can supply wood to a chart; water generating wood inside a winter branch is the system's image of potential held in reserve.

How Hai relates to the other branches

RelationshipPartnersWhat it means
Six Harmony (六合)Yin 寅A fixed pairing read as natural rapport — the classical “good match” relationship between two branches.
Three Harmony (三合)Mao 卯 · Wei 未Same elemental trine. Two branches of a three-branch combination share an element and are read as reading each other's instincts correctly.
Clash (冲)Si 巳Direct opposition, six positions apart. Read as movement and friction rather than as misfortune — the branches pull in opposite directions.
Harm (害)Shen 申Harm. A quieter relationship than clash — small ongoing friction that compounds if unaddressed.
Break (破)Yin 寅Break. The least discussed of the branch relationships: a destabilising pairing, classically read as undermining rather than opposing.
Self-punishment (自刑)Hai 亥 (repeated)The same branch repeating. For Chen, Wu, You and Hai this is self-punishment — read as an internal dynamic rather than a clash with another person.
A relationship between branches is not a verdict. It describes where energy moves and where it meets resistance — which only means something once the day master and the season are known.

Where Hai is strong

Where it goes wrong

The 21:00–23:00 birth hour

The Hai hour (21:00–23:00) is the last hour of the traditional day and begins the transition into the Zi hour. Hour-pillar Hai charts often describe people who come alive late in the evening, when the demands of the day have finished.

In traditional medicine the branch is also assigned to kidneys, bladder and the head, which is why classical texts read chronic conditions through the branch that governs the season they began in.

Questions about Hai

What element is the Hai branch?
Hai is Yin Water — the second water branch, associated with early winter and the north-west direction. Its main hidden stem is Ren, which is Yang Water, so the branch pairs a Yin container with a Yang content — the mirror image of Zi.
Why does Hai contain wood?
Water generates wood, so Hai's middle qi is Jia (Yang Wood). This means a chart short on wood can draw it from Hai, but the wood arrives mixed with a great deal of water — useful for growth, less useful for structure.
What happens when Hai clashes with Si?
巳亥相冲 is water against fire. Classical readings connect the pair to sudden changes of plan driven by outside events rather than by personality, which is why it often appears in charts describing relocations or abrupt career turns.
Is Hai the same as the Pig?
The Pig is the year animal; Hai is the branch. The branch also appears in the hour pillar of anyone born between 21:00 and 23:00, and in the day branch for those born on a Hai day.

The other branches

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Traditional systems, written for self-reflection. Not a substitute for professional advice.