The unique characters that define the 12 zodiac signs in Chinese astrology.

In Feng Shui and Chinese metaphysics, the "independent" characters you see (like Zi 子 for Rat or Wu 午 for Horse) are called the Earthly Branches (地支).

The reason these special characters are used instead of the standard words for the animals (like Shu 鼠 or Ma 馬) is rooted in history, science, and the specific "job" these characters perform in a Feng Shui analysis.

1. They formulate the science and logic, not just symbolic.

In Feng Shui, the 12 signs aren't just "animals"—they are mathematical variables.

• The zodiac signs were added later as a mnemonic (memory aid) for the general public who couldn't read or write the complex calendar system.²

  
  

• The branches are technical terms used to calculate the movement of stars, the changing of seasons, and compass degrees. Using the character Zi (子) is like using a variables in algebra; it carries a specific weight, element (Water), and polarity (Yang) that the word "Rat" does not communicate to a practitioner.

  
  

2. Space and direction according to the Chinese compass - the Luo-Pan.

When you look at a Feng Shui compass (Luo Pan), you will see these 12 characters.³ They represent precise directional sectors of 30° each.

Zi (子) is exactly North (0°).

Wu (午) is exactly South (180°).

If a Feng Shui master simply said "The Rat Direction," it might sound like a folk tale. By using Zi, they are referencing a specific degree on the compass that interacts with the "Heavenly Stems" to form the 24 Mountains (the grid used to align buildings).

3. Time keeping - the odd hours straddling the divisions of the day.

The Earthly Branches were originally a system for measuring the 12 "double-hours" of a day and the 12 months of a year.

• Zi (子) represents 11:00 PM – 1:00 AM (the peak of Night/Yin).

  
  

• Wu (午) represents 11:00 AM – 1:00 PM (the peak of Day/Yang).

  Because Feng Shui is about balancing Qi over time, these characters allow a practitioner to calculate when a house’s energy is strongest or weakest throughout the day and year.

  
  

4. Secrets within the hidden stems.

This is the most "insider" reason: Each independent character actually "hides" other elements inside it.

For example, the character Chen (辰) is the Dragon.9 In Feng Shui logic, Chen isn't just "Earth"—it is a "tomb" or "storage" for Water and also contains a bit of Wood. Using the specific Branch character allows practitioners to see these hidden layers of energy that the simple animal name doesn't show.

Summary table.

Zodiac	Earthly Branch	Feng Shui Direction	Primary Element
Rat	Zi (子)	North	Water
Horse	Wu (午)	South	Fire
Rabbit	Mao (卯)	East	Wood
Rooster	You (酉)	West	Metal