The ten heavenly stems and twelve earthly branches

A Four Pillars of Destiny (BaZi) chart is written in eight characters: four heavenly stems on top and four earthly branches beneath them, one pair for each of the year, month, day and hour pillars. Every stem and every branch belongs to one of the five elements and is either yin or yang. In the classical books the stems are the part that moves and acts, while the branches stay in place and keep the months and seasons in a fixed order.

The previous lesson covered yin and yang and the five elements. This lesson places them on the eight characters of a chart: which element each stem and each branch belongs to, whether it is yin or yang, and what part the stems and the branches each play.

Stems above, branches below

When The True Interpretation of Ziping (子平真诠; Qing dynasty, 18th century) discusses the ten stems and twelve branches, it first explains that every element has both stems and branches. Take Wood: Yang Wood and Yin Wood are the yang and yin of Wood as it flows through the sky, while the Tiger and the Rabbit are the yang and yin of Wood as it rests on the earth. The stems move above and the branches receive them below; the branches stay on the earth and the stems act on them from above. The book offers a comparison: Yang Wood and Yin Wood are like the official in charge of a region, and the Tiger and the Rabbit are like the territory that official governs. Yang Wood holds office in the Tiger and Yin Wood in the Rabbit, just as a prefect sits in his prefecture and a magistrate in his county, each presiding over one month of the year.

The True Interpretation of Ziping · On the Ten Stems and Twelve Branches

So the stems and the branches are not two unrelated sets of symbols. The same element is a flowing energy on the stems and a season set in place on the branches, and the two answer each other from above and below. When you look at a stem in a chart, it is worth checking whether the branches hold anything of the same element that answers it.

The ten stems: element and polarity

The ten heavenly stems divide each of the five elements into a yang and a yin side:

Counted in order, the first, third, fifth, seventh and ninth stems are yang, and the second, fourth, sixth, eighth and tenth are yin. Dripping Heavenly Marrow (滴天髓) opens its verses on the heavenly stems with the two poles of yin and yang: all five yang stems are yang, but Yang Fire is the most yang of them; all five yin stems are yin, but Yin Water is the furthest into yin. The original notes to Dripping Heavenly Marrow explain that Yang Fire receives the essence of yang, making it the yang within yang, and Yin Water receives the essence of yin, making it the yin within yin.

Dripping Heavenly Marrow · Heavenly Stems; Dripping Heavenly Marrow · Heavenly Stems, original notes

The difference between yang and yin stems is one of nature, not of strength. In the same chapter, Dripping Heavenly Marrow Elucidated (滴天髓阐微; Qing dynasty, 19th century) points out that Yang Wood and Yin Wood are one Wood, Yang Fire and Yin Fire one Fire, and so on: the yang and yin of an element are a single energy, and the difference is that yang is firm and yin is gentle, yang is vigorous and yin is yielding. It also holds that the ten stems are not best understood through fixed images alone, such as taking Yang Wood as dead wood and Yin Wood as living wood.

Dripping Heavenly Marrow Elucidated · Heavenly Stems

As the previous lesson noted, The True Interpretation of Ziping also says that in energy Yang Wood is the stronger, while in substance Yin Wood is the firmer. So a Day Master, the stem of the day pillar, is not weak just because it is a yin stem, nor strong just because it is a yang stem. The Day Master’s strength depends on the month branch and the branches, and is left to the lessons on Day Master strength; yin stems also move through the twelve life stages in their own way, covered in the lesson on the twelve life stages.

The True Interpretation of Ziping · On the Ten Stems and Twelve Branches

The twelve branches: element, polarity and month

The twelve earthly branches likewise each have an element and a polarity. They follow one another in a ring that matches the twelve months of the year: the Tiger is the first month, the Rabbit the second, and so on round to the Ox, the twelfth.

The months in the table are solar months, set by the solar terms, not the months of the lunar calendar; how they are set is covered in the lesson on setting up the four pillars. Wood, Fire, Metal and Water each hold one season. The four Earth branches, the Dragon, the Goat, the Dog and the Ox, each sit at the end of a season and carry the change into the next.

Commentary on the True Interpretation of Ziping · On the Ten Stems and Twelve Branches; Commentary on the True Interpretation of Ziping · On How to Use the Mixed Energies

There is more than one way to divide the branches into yin and yang. Dripping Heavenly Marrow Elucidated, in its discussion of the earthly branches, gives the division practitioners commonly use: the Rat, Tiger, Dragon, Horse, Monkey and Dog are yang; the Ox, Rabbit, Snake, Goat, Rooster and Pig are yin. The table above follows it. The book also points out a detail. The Rat and the Horse are yang branches, yet the Rat is ruled by Yin Water and the Horse by Yin Fire, both yin stems; the Snake and the Pig are yin branches, yet the Snake is ruled by Yang Fire and the Pig by Yang Water, both yang stems. The book calls the first pair yang in body and yin in use, and the second pair yin in body and yang in use. Which stems each branch holds inside it is the subject of the next lesson.

Dripping Heavenly Marrow Elucidated · Earthly Branches

Stems act, branches hold

The True Interpretation of Ziping sums up how the stems and the branches share the work in one line:

干动而不息，支静而有常。

Our translation: The stems move and never rest; the branches stay still and keep a constant order.

The stems keep moving, changing from year to year; the branches keep their places in a fixed order. The book goes on to say that every stem passes through the twelve months the branches stand for, and that the life stages, such as birth, peak, stored and spent, are set by this.

The True Interpretation of Ziping · On the Rise and Fall of Yin and Yang

In its chapter on the ten stems and twelve branches, the book gives a concrete example: a Tiger month is not always paired with Yang Wood, and a Rabbit month is not always paired with Yin Wood. The month branch never changes, since the first month is always the Tiger and the second always the Rabbit, but the stem placed above it changes every year. This is what "stems act, branches hold" looks like in a chart.

The True Interpretation of Ziping · On the Ten Stems and Twelve Branches

Where it discusses favorable and unfavorable elements, the book makes this division of work more concrete. The stems belong to heaven, moving and taking action; the branches belong to earth, staying still and waiting to be put to use. And a stem stands for one thing only, while a branch often holds more than one, so the same element works differently on a stem and on a branch. Commentary on the True Interpretation of Ziping (子平真诠评注; ROC, 1936) adds that each branch keeps to its own ground, and its force does not show while nothing stirs it; only when a clash or a combination sets it in motion does its effect appear. How branches combine and clash is covered in the lessons on combinations and clashes; how the stem and the branch of a decade phase work differently is left to the lessons on decade phases.

The True Interpretation of Ziping · On How Favorable and Unfavorable Differ Between Stems and Branches; Commentary on the True Interpretation of Ziping · On How Favorable and Unfavorable Differ Between Stems and Branches

Try it on your chart

1. Write your eight characters in two rows: the four stems on top and the four branches below.
2. Beside each character, note its element and polarity, for example "Yang Fire" for a stem or "yin Water" for a Pig branch.
3. Circle the Day Master and see whether it is a yang or a yin stem. Remember: a yin stem does not mean weak, and a yang stem does not mean strong.
4. Look at the month branch and write down its season. This is the season you were born in; later, when you judge strength and take the structure, the month branch always comes first.
5. Note whether your chart holds the Rat, the Horse, the Snake or the Pig: their polarity is the opposite of the stem that rules them, which you will see again when the next lesson lists the hidden stems.

See also: Hidden stems: what each branch holds

See also: Setting up the four pillars: solar months, the year boundary and the midnight hour

See also: The twelve life stages