Resolve the city
The selected city supplies latitude, longitude and an IANA time-zone identifier. Free-text city names are not silently accepted.
Calculation transparency
How Bazi Clarity calculates a BaZi chart.
This page documents the rules, data inputs, confidence limits and automated checks used by the free tools and 65-page report. It is a reproducibility record—not a claim of scientific prediction.
Calculation sequence
From civil birth details to Three or Four Pillars
Recover historical time
The IANA zone determines the UTC offset and daylight-saving rule that applied on the birth date—not merely the city’s current offset.
Apply true-solar correction
Longitude relative to the standard meridian and an equation-of-time approximation adjust civil wall time. The correction is displayed in the result.
Apply calendar boundaries
The year changes at Li Chun; months change at solar-term boundaries; the configured day rollover is midnight.
Build Pillars
Year, Month and Day Pillars are generated from the corrected calendar input. The Hour Pillar is created only when a birth time is supplied.
Calculate chart evidence
Visible stems, branch elements and weighted Hidden Stems are adjusted by seasonal strength. Every report page references calculation evidence IDs.
Unknown birth time
No time means no invented Hour Pillar.
When time is missing or marked unknown, the system uses the Year, Month and Day Pillars only. Hour-dependent interpretation and Luck Pillars are omitted or marked conditional. Noon may be used internally only to obtain date-level calendar context; it is never presented as the client’s birth hour.
Confidence labels
High means directly calendar-derived from verified inputs. Medium means a disclosed interpretive weighting model is applied. Conditional means a required birth detail is unavailable or the conclusion depends on school-specific conventions.
Source and implementation references
External data is separated from interpretation.
- IANA Time Zone Database for historical civil-time rules.
- Hong Kong Observatory: 24 Solar Terms for an astronomical description of solar terms.
- NOAA solar calculation details as a published reference for solar-time equations and their limitations.
- lunar-javascript as the calendar implementation used for Pillar and Luck-cycle primitives.
These sources do not endorse Bazi Clarity or metaphysical prediction. They support only the time, calendar and implementation layers identified above.
Interpretive limits
What the calculation cannot prove
BaZi is a traditional symbolic framework. A deterministic chart calculation does not make personality claims, future events or life outcomes scientifically established. Interpretation is presented as structured self-reflection and planning language. It must not replace medical, legal, financial, psychological, relationship or other qualified professional advice.