Earthly Branch · Hài
Hài (亥)
the opening of winter — broad Water carrying the seed of next year's Wood
- Zodiac correspondence:
- Pig / Boar
- Element:
- Water
- Season:
- early winter
- Hours:
- 21:00–23:00
- Lunar month:
- the 10th lunar month
- Hidden stems:
- Yang Water (壬) · Yang Wood (甲)
The twelfth Earthly Branch — early winter, rising Water with hidden Wood. Its zodiac animal is the Pig.
Overview
Hai (亥) is the twelfth and last Earthly Branch, and the rule holds one final time: Hai is the branch; the Pig — also rendered Boar — is the popular Chinese-zodiac animal that corresponds to it. Hai is not 'the Pig'; it is Hai, a calendrical unit, with the Pig as its familiar label.
As a branch, Hai is the opening of winter — the 10th lunar month, late evening, the year turning inward. Its element is Water, broad and rising, and one of the four 'growth-opening' branches that begin a season. What makes Hai distinctive is the Wood hidden in it: this Water branch is where Wood is born, the seed of next spring already forming as the cycle closes and prepares to begin again.
As a unit of time
As time, Hai rules 21:00–23:00 (the 亥時 double-hour), the 10th lunar month at winter's opening, and a north-northwest position. Its pillar placement fixes which layer of the chart this rising Water colours.
Hidden stems (藏干)
Hai's hidden stems (藏干) are Yang Water (壬) as the main qi, with Yang Wood (甲). The buried Wood is the key: this Water branch is the birthplace of Wood (Water generates Wood), so Hai closes the cycle of twelve while already carrying the seed of the next spring. The hidden stems hold that renewal inside the branch.
Clashes, trinities, combinations
Hai's clash (六沖) is with Si (巳, the Snake) — the Water-against-Fire, winter-against-summer axis. It opens the Wood trinity (三合) 亥卯未 (Hai–Mao–Wei), and its six-combination (六合) is with Yin (寅, the Tiger), combining toward Wood. These are structural relationships between chart positions, not predictions.
Cross-system reference
| System | Closest archetype | Note |
|---|---|---|
| Zi Wei Dou Shu | One of the twelve fixed cells of a Zi Wei chart — the 亥 position a palace sits on | In Zi Wei the twelve Earthly Branches are the chart's twelve fixed cells: every palace occupies a branch, and a chart's 命宮 (Life Palace) can land on 亥. Its Bazi clash partner 巳 (Snake) sits in the cell directly opposite — what Zi Wei reads as the 對宮 (opposite palace) on the same axis. Same twelve branches, used as the spatial frame for the palaces, not as a Bazi pillar. |
| Chinese zodiac (生肖) | The Pig / Boar — the popular animal label for the branch Hai | The Pig is the everyday zodiac's name for Hai; the branch Hai — its Water element, hidden Wood, time and interactions — is the technical unit a Bazi chart reads. |
| Western astrology | A loose structural parallel only — twelve divisions of a cycle | No sign maps to a branch; the branches are calendrical, not personality signs. The only parallel is the shared twelve-fold division. |
The Chinese zodiac animal is a popular label for the branch, not the branch itself, and there is no branch-to-Western-sign mapping. Cross-system anchors are a loose heuristic; an Earthly Branch is a calendrical unit with hidden stems, which neither the zodiac nor Western astrology shares.
Reading this descriptively
Hai describes a position in time and its elemental character — early-winter rising Water — not a personality, not a destiny, and not 'you are a Pig'. It is read against the rest of the chart, and the same branch plays out very differently across different lives.
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