Earthly Branch · Sì
Sì (巳)
rising summer Fire — the forge, bright and coiled, Metal hidden in the heat
- Zodiac correspondence:
- Snake
- Element:
- Fire
- Season:
- early summer
- Hours:
- 09:00–11:00
- Lunar month:
- the 4th lunar month
- Hidden stems:
- Yang Fire (丙) · Yang Earth (戊) · Yang Metal (庚)
The sixth Earthly Branch — early summer, rising Fire with hidden Metal. Its zodiac animal is the Snake.
Overview
Si (巳) is the sixth Earthly Branch, and the distinction stands: Si is the branch; the Snake is the popular Chinese-zodiac animal that corresponds to it. Si is not 'the Snake' — it is Si, a calendrical unit, with the Snake as its familiar label.
As a branch, Si is the rising fire of early summer — the 4th lunar month, late morning, the heat beginning to build. Its element is Fire, bright and coiled like a forge, and one of the four 'growth-opening' branches that begin a season. What makes Si distinctive is the Metal hidden in its heat — the forge that will, by autumn, produce Metal.
As a unit of time
As time, Si rules 09:00–11:00 (the 巳時 double-hour), the 4th lunar month at summer's opening, and a south-southeast position. Its pillar placement fixes which layer of the chart this rising Fire colours.
Hidden stems (藏干)
Si's hidden stems (藏干) are Yang Fire (丙) as the main qi, with Yang Earth (戊) and Yang Metal (庚). The buried Metal is the surprise: this Fire branch is also where Metal is born (the 'long life' stage of Metal), so Si carries the seed of the element its heat seems to oppose. The hidden stems hold that paradox inside the branch.
Clashes, trinities, combinations
Si's clash (六沖) is with Hai (亥, the Pig) — the Fire-against-Water, summer-against-winter axis. It opens the Metal trinity (三合) 巳酉丑 (Si–You–Chou), and its six-combination (六合) is with Shen (申, the Monkey), combining toward Water. 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 巳 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 巳. Its Bazi clash partner 亥 (Pig) 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 Snake — the popular animal label for the branch Si | The Snake is the everyday zodiac's name for Si; the branch Si — its Fire element, hidden Metal, 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
Si describes a position in time and its elemental character — early-summer rising Fire — not a personality, not a destiny, and not 'you are a Snake'. It is read against the rest of the chart, and the same branch plays out very differently across different lives.
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