Si (Snake)

Earthly Branches

巳、蛇

Definition

Si is the sixth Earthly Branch, belonging to Yin Fire, associated with the Snake zodiac sign, and corresponds to the Si Hour (09:00–11:00). Si is the ‘birthplace’ of Fire, an advancing rather than peak fire (Dijian Sui: ‘Si Fire is yang within yin, its qi still growing’; Yuanhai Ziping: ‘Fire is born at Si’). It internally conceals Bing Fire, Wu Earth, and Geng Metal; its nature is warm yet reserved, symbolizing wisdom, strategy, and transformative power. Si Fire embodies the image of the snake—skilled in strategy and adept at concealing its true intentions.

How to Find

Si Fire is identified from the Earthly Branches of the Four Pillars in a Bazi chart. If Si appears in the Year Branch, the native belongs to the Snake zodiac; if Si appears in the Day Branch, the Spouse Palace is governed by Si Fire. Si Fire is strongest during the Si Month (lunar fourth month), when it is in season.

Attributes

elementFire

yinYangYin

zodiacSnake

seasonSummer

time09:00–11:00

Chart Meanings

Year Pillar：Si Fire in the Year Branch suggests ancestors or elders skilled in strategy; the native tends to think deeply during childhood.

Month Pillar：Si Fire in the Month Branch indicates strategic aptitude in career—suitable for professions such as planning or consulting.

Day Pillar：Si Fire in the Day Branch implies a spouse who is intelligent and strategic, though possibly reserved or deep-minded.

Hour Pillar：Si Fire in the Hour Branch suggests intelligent, strategic offspring and strong planning ability in later life.

Combinations

Si-Shen Combination forming Water

Si and Shen form a Six Harmonies; transformation into Water requires Ren/Gui stems to penetrate and induce the transformation—otherwise it becomes a punitive combination (xing he), signifying repeated fluctuations (as Ziping Zhenquan explicitly states). Omitting these conditions risks misjudgment.

Si-Hai Clash

The clash between Si and Hai signifies Water-Fire conflict, often manifesting as emotional instability and requiring attention to cardiovascular health.

San He Jin Ju (Si-You-Chou Triple Combination forming Metal)

The Si-You-Chou triple Metal combination forms a true Metal configuration only when You and Chou are both present, no Bing/Ding Fire penetrates, and no Wu/Ji Earth buries it—otherwise the configuration is damaged (per Ziping Zhenquan). It must not be stated absolutely.

Examples

A person born on a Gui-Si Day has Si Fire as Direct Wealth in the Day Branch—suggesting a spouse skilled in financial management and possessing a reserved disposition.