Source first
The local date, clock time, birthplace and historical timezone form the starting record.
Scope of this page
This is a method reference, not a promise that one BaZi school is the only valid school. A calculation layer can be made reproducible: the date, local time, location, calendar boundary and branch assignment can be stated. An interpretation layer may still differ across practitioners, especially around useful elements, day-boundary conventions and how much weight to give a symbol.
Calculation layers
| Birth record | Local date, local clock time, birthplace and source confidence. |
|---|---|
| Time normalization | Historical timezone and daylight-saving status for the birthplace and date. |
| Solar-time check | Birthplace longitude correction when the method is enabled or relevant to a boundary. |
| Calendar conversion | Solar-term month logic and the Li Chun annual boundary. |
| Pillar assignment | Year, Month, Day and Hour stem-branch rules, including the Zi-hour convention. |
| Interpretation | Day Master, Ten Gods, Five Elements, useful factors, Luck Pillars and the user’s question. |
What the calculator should show
- The original local record before correction.
- The birthplace and timezone used.
- Whether DST was active or requires a historical check.
- The corrected time and whether the Hour Pillar boundary moved.
- The day-change rule when the birth is in the Zi-hour window.
- A confidence note when birth time or birthplace is uncertain.
What remains a school choice
Different BaZi schools can disagree about the exact treatment of early and late Zi hour, some hidden-stem weighting, useful-god selection and interpretation emphasis. Those differences should be named instead of presented as a hidden algorithmic fact. If a chart depends on one disputed convention, preserve the alternative and explain what changes.
Unknown or approximate birth time
Without a reliable birth hour, the Year, Month and Day layers may still support a partial chart, but the Hour Pillar is not confirmed. If the record gives a range, build candidate charts. State which observations are stable across the candidates and avoid precision claims that depend on the missing hour.
Next step
Build a chart · Compare competing results · Handle an uncertain hour with the method visible.
FAQ
- Does this methodology guarantee a correct interpretation?
- No. It makes the calculation basis reproducible; interpretation still depends on method and context.
- Does the calculator always apply true solar time?
- The result should state whether a correction was applied and whether it changed the Hour Pillar boundary.
- What happens when the birth hour is unknown?
- Use a partial chart or candidate Hour Pillars and lower the confidence of hour-specific claims.
Related guides
Free BaZi Calculator
BaZi Calculator with True Solar Time
BaZi Birth Data Source Checklist
BaZi Luck Pillars
Why BaZi Calculators Differ
BaZi Li Chun vs Chinese New Year
bazi calculation methodology
four pillars calculation rules
bazi chart accuracy
bazi solar terms
bazi timezone method