Heavenly Stems & Earthly Branches

The Heavenly Stems are ten in total. Each one represents one of the five elements — Wood, Fire, Earth, Metal, or Water — in either a Yang or Yin form. Yang is the active, outward, initiating side of an element. Yin is the receptive, inward, refining side. Together, the ten stems cover every possible expression of the five elements.

Here they are:

Each stem carries a distinct flavour even within its element. For example, Jia (Yang Wood) is like a tall tree — strong, upright, and growing upward. Yi (Yin Wood) is more like a vine or grass — flexible, adaptive, and able to work around obstacles. Same element, very different energy. This applies across all five elements: Yang is the raw, expansive force, and Yin is the refined, shaped version.

The Heavenly Stems sit on top of the pillars, and because they're in the open, their energy is considered more visible and external. When you look at someone's chart, the stems are what you see first — they're the surface expression of the energy in each pillar.

The Earthly Branches are twelve in total, and they're the reason you have a zodiac animal. Each branch corresponds to one of the twelve animals, and like the stems, each one carries an element and a polarity. But the branches go further — they hold more complexity beneath the surface, which we'll get to later.

Here they are:

The branches also represent the twelve months of the year and the twelve two-hour blocks of the day, so they carry a strong connection to natural cycles — seasons, daylight, the rhythm of growth and rest. This is part of why Bazi is so tied to the natural world: the branches aren't abstract symbols, they're rooted in the actual flow of time and nature.

While the Heavenly Stems are considered more visible and external, the Earthly Branches are deeper and more internal. They hold more going on beneath the surface — literally, because each branch contains hidden stems inside it. But that's a topic for its own page (Hidden Stems).

Stems and branches don't pair up randomly. They follow strict rules. A Yang stem always sits on top of a Yang branch, and a Yin stem always sits on top of a Yin branch. You'll never see a Yang stem paired with a Yin branch in a valid pillar.

Because of this rule, only 60 unique stem-branch combinations are possible out of the theoretical 120. This set of 60 combinations is called the Jiazi cycle (甲子, "Jia-Zi cycle"), named after the very first pairing: Jia (甲, Yang Wood stem) on top of Zi (子, Yang Water branch). The cycle runs through all 60 pairings and then starts over, which is why the Chinese calendar repeats on a 60-year cycle.

Every pillar in your chart — Year, Month, Day, and Hour — is one of these 60 combinations. So when you see a chart, you're not just looking at four random pairs. You're looking at four specific points in the Jiazi cycle, each one carrying a unique blend of stem and branch energy.

If the Four Pillars are the structure of a Bazi chart, the Heavenly Stems and Earthly Branches are the substance. They're what give each pillar its elemental identity. Without knowing what the stems and branches mean, you can't read a chart — it would be like trying to read a sentence without knowing the alphabet.

The stems tell you the outward energy of each pillar. The branches tell you what's going on underneath. And because each branch contains hidden stems inside it, the branches are actually carrying more information than they appear to on the surface. That hidden layer is one of the things that makes Bazi so detailed, and it's what we'll explore on the next page.