Sixty Jiazi (六十甲子) — The 60 Stem-and-Branch Pillars

Why the ten stems and twelve branches make sixty pillars, how a pillar is read, and the first twelve of the cycle — Jia Zi through Yi Hai — in full.

Quick answer

What is the sixty jiazi cycle?

The ten heavenly stems and twelve earthly branches pair up in a sixty-step cycle, because only sixty of the possible combinations repeat. Every year, month, day and hour in the Chinese calendar is one step in this cycle, which is what a four pillars chart is built from.

Why sixty, and not a hundred and twenty

A stem and a branch can only sit together when they share a polarity. There are five yang stems and five yin stems, six yang branches and six yin branches, and a yang stem never pairs with a yin branch. Each stem therefore works with six of the twelve branches rather than all twelve, and ten times six is sixty.

The consequence is that the cycle repeats as a whole only after sixty steps. A year pillar takes sixty years to return; a day pillar takes sixty days. This is the reason two people born in the same zodiac year can have entirely different year pillars — the animal tells you the branch and says nothing about the stem above it.

The sixty jiazi laid out as ten stems by six branches. A stem and a branch can only sit together when they share a polarity, which is why the grid is half empty and the full cycle takes sixty steps rather than a hundred and twenty. The twelve highlighted cells are the pillars covered on this site.

The first twelve

Each pillar below is read as a unit: the stem above, the branch below, what the branch hides inside it, and how the two characters meet. The dates on each page are calculated from the same engine that runs the chart calculator, so they stay current.

甲子

Jia Zi

Yang Wood over the Rat branch (Water). Gold in the Sea.

Wood / Water · nayin Gold in the Sea

乙丑

Yi Chou

Yin Wood over the Ox branch (Earth). Gold in the Sea.

Wood / Earth · nayin Gold in the Sea

丙寅

Bing Yin

Yang Fire over the Tiger branch (Wood). Fire in the Furnace.

Fire / Wood · nayin Fire in the Furnace

丁卯

Ding Mao

Yin Fire over the Rabbit branch (Wood). Fire in the Furnace.

Fire / Wood · nayin Fire in the Furnace

戊辰

Wu Chen

Yang Earth over the Dragon branch (Earth). Wood of the Great Forest.

Earth / Earth · nayin Wood of the Great Forest

己巳

Ji Si

Yin Earth over the Snake branch (Fire). Wood of the Great Forest.

Earth / Fire · nayin Wood of the Great Forest

庚午

Geng Wu

Yang Metal over the Horse branch (Fire). Earth by the Roadside.

Metal / Fire · nayin Earth by the Roadside

辛未

Xin Wei

Yin Metal over the Goat branch (Earth). Earth by the Roadside.

Metal / Earth · nayin Earth by the Roadside

壬申

Ren Shen

Yang Water over the Monkey branch (Metal). Metal of the Sword's Edge.

Water / Metal · nayin Metal of the Sword's Edge

癸酉

Gui You

Yin Water over the Rooster branch (Metal). Metal of the Sword's Edge.

Water / Metal · nayin Metal of the Sword's Edge

甲戌

Jia Xu

Yang Wood over the Dog branch (Earth). Fire on the Mountain Top.

Wood / Earth · nayin Fire on the Mountain Top

乙亥

Yi Hai

Yin Wood over the Pig branch (Water). Fire on the Mountain Top.

Wood / Water · nayin Fire on the Mountain Top

How a pillar is read

Four things are checked before a single judgement is made. First the two characters themselves — a stem has an element and a polarity, and so does a branch. Second the hidden stems inside the branch, because a branch is not one element but up to three, with a main qi and lesser ones. Third whether the stem has a root in that branch, which decides whether the quality of the stem is actually available to the chart. Fourth how the stem and branch relate — whether the branch feeds the stem, drains it, or constrains it.

Only after those four are settled does a practitioner ask what the pillar means in the chart it belongs to. The same pair in the year pillar and in the day pillar are not the same statement, because the year is read as background and the day as the self.

Common questions

Why are there sixty combinations and not a hundred and twenty?

Because only half of the ten-by-twelve grid is possible. A stem and a branch can sit together only if they share a polarity — yang with yang, yin with yin — so each stem pairs with six branches rather than twelve. Ten times six is sixty, and that is the whole cycle.

Is the sixty-year cycle the same as the sixty-day cycle?

The arithmetic is the same but the clock is different. A year pillar advances once per year, so the same pair returns in sixty years. A day pillar advances once per day, so the same pair returns every sixty days — which is why the same stem-and-branch pair shows up in a chart as a year and, twenty-odd years later, as a day.

Is the sixty-jiazi cycle the same as the zodiac?

No. The zodiac uses the twelve branches only, which is why the animal repeats every twelve years. The sixty-jiazi cycle uses the branches with the ten stems, which is why each animal year comes in five different varieties and a full cycle takes sixty years.

Where does the nayin table come from?

It is a fixed classical table, not a calculation: each neighbouring pair of pillars is assigned an image in one of the five elements, thirty images in all. It is one of the oldest layers of reading a pillar as a picture rather than as two characters, and it is read alongside the stems and branches rather than instead of them.

Where this sits in the system

Stems and branches explained The four pillars The ten day masters The sixty-year cycle Hidden stems Rooting

See your four pillars

The calculator is free and lives on the reports page: enter your birth date, time and time zone and it builds the full chart. The written readings below it are optional — one payment each, yours to keep.

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