How BaZi charts and archetypes are calculated.

There are 10 sky signs and 12 animal signs (the Chinese zodiac animals). They pair up in a repeating cycle of 60. Your year, month, day and hour are each one sky sign over one animal sign: 8 characters in all. These four pairs are called the four pillars.

• Sky signs are the five elements, each in a Yang (outward) and a Yin (inward) form.
• Animal signs each hide one to three elements inside them, and we count those too.
• Your hour is adjusted to where the sun really was in your birth city, when we know the city. For births between 11 pm and midnight, the hour counts as the first hour of the night, but your day stays the calendar day.

The top character of your day pair is your core element, the one that stands for you. There are 10: Yang and Yin Wood, Fire, Earth, Metal and Water, from the tall tree to the quiet rain. Every other character is read by how it pulls on your core element. Those pulls are the forces in your chart.

To work out how much of each element you carry, we weigh all 8 characters, including the elements hiding inside the animal signs. Your birth month weighs the most, because the season you are born in colours everything.

The classical books are clear that your birth month sets the theme of your chart. In their words, “八字用神，專求月令”: look for the key to a chart in its month. So we read the strongest force in your chart from your birth month, not from a count of which force appears most.

Every chart lands on one of 8 forces: the Leader, Warrior, Builder, Adventurer, Scholar, Mystic, Creator or Rebel. We checked this rule against 51 worked charts in a classical handbook (子平真詮). All 51 match, and 3 more cases where the book uses two forces at once are noted in our tests.

Next we ask whether your core element has a lot of backup in the chart or a lot of pressure on it. We look at three things: whether your birth season suits it, whether it has roots in the animal signs, and whether the other sky signs support it. The answer places your chart on a scale from very strong to very gentle.

This shapes the detail in the full reading. It never changes your guardian.

The old books also weigh the weather of your birth season. A chart born in deep winter needs warmth, so Fire. A chart born in high summer needs moisture, so Water. When that element is also the one that balances your chart, and you have little of it, we name it as an element that brings you balance. We never call any element bad for you.

Very rarely, a core element is so alone in a chart that the old books say it stops resisting and simply goes with the strongest force, like a leaf on a river. We call this only when the evidence is overwhelming, so it is rare on our site by design.

BaZi is not one single rulebook. Over 1,000 years, different Chinese masters wrote different books, and they sometimes read the same birth chart in different ways.

We follow one of them: a classical handbook written about 300 years ago, building on rules that are about 1,000 years old. Your guardian spirit comes from two things these rules agree on well: your core element and the strongest force in your chart.

Your “elements that bring you balance” and “elements to use in moderation” are a finer point, and here the old books often disagree. We tested our engine against charts printed in classical books. On charts from the same tradition as our handbook, our suggestions matched the book in most cases. On books from other traditions, they matched only about half the time. That is not a bug we can fix by tuning. It is how the tradition works.

So please read your balance elements as a gentle suggestion from one school, not as a verdict. Nothing in your chart is “good luck” or “bad luck”. It is a mirror for reflection, not a forecast.

10 core elements times 8 forces gives 80 guardians: 8 for each core element and 16 for each element. The force is your chart's theme; your core element is the voice it speaks in. Yang Fire, the sun, with the Creator as its strongest force is The Fire Creator. With the Builder it is The Fire Harvester.

Two more forces, the Friend and the Rival, are your own element showing up again. They never lead a chart by themselves: months that carry them take their theme from another force, as described above. Meet all 80 guardians.

Every BaZi tool makes choices. These are ours, listed so you can see where our reading is a choice rather than a rule. They use classical terms, so skip them if you are new.

• Ren Yuan Si Ling (人元司令), which hidden stem rules the month depending on days since the solar term, is not implemented. We use revealed stems and the main qi only.
• Keeping an officer or seal main qi over a revealed middle or residual qi (outside storage months) is a rule we inferred from the book's worked charts, not a sentence in it.
• When several stems are revealed in a storage month, we take the first in order; the book sometimes uses both.
• Combinations are listed, not transformed. Stem combinations (天干五合), six harmonies and three harmonies never change an element in our count.
• Follow-structure thresholds are program thresholds. We do not separate true from false follows, and transformation and other special structures are not implemented.
• Climate covers only the winter and summer extremes. Month-by-month tables for each Day Master, and dry or damp earth, are not modelled.
• Strength weights (month 4, the 0.8 / 0.15 / 0.05 split, the directional 1.5) and the cut-offs are calibrated.
• Historic time-zone and daylight-saving edge cases can still be off by one hour.

BaZi is a traditional way of reading people, not a scientific instrument. Our guardians and element readings are for self-reflection and fun. They are not medical, financial, legal or psychological advice, and they make no claims about health. A wrong birth time changes your hour pair and can change the strength reading.

Read our editorial policy, the sources we work from, and who we are.