Bornchart is not AI guessing.
Your chart is computed from calendrical rules — the same rules Chinese practitioners have used for over a thousand years. AI, if used at all, is reserved for explaining the result, never for guessing the chart itself.
What the calculation actually does
A BaZi chart is not a personality quiz. It is a deterministic mapping from a moment in time to eight Chinese characters — your Four Pillars. Given the same birth date and time rules, the result is identical every time, for every person who computes it. There is no randomness, no large language model, no probabilistic guess.
Bornchart performs four steps:
- Convert your Gregorian birth date into the Chinese solar calendar.
- Apply true solar time — timezone, historical daylight saving, birthplace longitude, and the Equation of Time.
- Map the year, month, day, and hour onto the 10 Heavenly Stems and 12 Earthly Branches — the building blocks of every Chinese astrological system.
- Derive your Day Master, Five Elements distribution, Ten Gods, and Luck Pillars from those eight characters using the rules documented in classical sources like 渊海子平 (Yuanhai Ziping) and 三命通会 (Sanming Tonghui).
The libraries we use
Bornchart is built on two open-source libraries that the serious Chinese metaphysics community relies on:
lunar-javascript— handles the Chinese calendar, solar terms (节气), Heavenly Stems, Earthly Branches, and date conversions.iztro— handles Zi Wei Dou Shu (紫微斗数) chart construction, including the 12 palaces and the 14 main stars.
Both are publicly auditable. If you compute your chart on Bornchart and on a reputable Chinese desktop tool, you should get the same Four Pillars. If they differ, one of us has a bug — and ours is fixable.
About time and location
The time printed on your birth certificate is civil time — the time used by clocks in your time zone. Bornchart first removes daylight saving time when it applies, then adjusts by birthplace longitude against the time zone's standard meridian.
For BaZi, this matters because the Hour Pillar changes every two hours. If your birth happened near the boundary of a two-hour window — say, 14:55 civil time — a five-minute correction can shift your entire Hour Pillar. That single change can flip your Day Master strength assessment, alter your Ten Gods configuration, and rewrite the structure of your chart.
The adjustment covers timezone, historical daylight saving time, birthplace longitude, and the Equation of Time — full apparent solar correction. Year and month pillars stay anchored to standard time (the solar-term axis), matching classical convention.
Where the words come from
The names you see on your result page — Day Master, Five Elements, Ten Gods, Luck Pillars, Annual Luck — are not marketing labels. They are translations of established Chinese terminology:
- Day Master = 日主 (rì zhǔ) — the Heavenly Stem of your Day Pillar, considered the core of your chart.
- Five Elements = 五行 (wǔ xíng) — Wood, Fire, Earth, Metal, Water; the elemental categories that every Stem and Branch belongs to.
- Ten Gods = 十神 (shí shén) — the ten relational roles other characters play in relation to your Day Master.
- Luck Pillars = 大运 (dà yùn) — the ten-year cycles your chart moves through across your lifetime.
- Annual Luck = 流年 (liú nián) — the energetic context of any given year.
These are not invented categories. They are how the system has been taught and recorded in classical Chinese texts for centuries.
Where AI fits in (and where it does not)
The chart itself is computed by deterministic rules. No language model is involved in deciding what your Day Master is or how many Wood characters you have. The math is the math.
If we use AI — for example, to help generate the prose in a written reading report — it is for explanation, not for calculation. The underlying chart always comes first, and the AI only translates the deterministic result into plain English. This distinction matters: it is the difference between describing what your chart says and inventing what your chart says.
"The chart is computed. The reading is written. We never let one masquerade as the other."
What this is not
Bornchart is a research and educational tool. The interpretations are based on classical metaphysical literature, not on clinical evidence. We do not claim to predict your future, diagnose your health, advise on your finances, or guarantee the outcome of any decision. All content on this site is for educational and entertainment purposes only — please make important life decisions with the help of qualified professionals.