Birth Data Required for a Bazi Chart
Prepare the birth date, local clock time, birthplace, calendar type and source uncertainty needed for a reproducible Bazi chart.
Overview
A reproducible Bazi chart needs the recorded birth date, local clock time, birthplace, calendar type and enough source detail to resolve the historical time zone. The original record should be preserved separately from any calendar conversion or solar-time correction. Sex is not needed to calculate the Four Pillars themselves, although a declared tradition may use it for later luck-cycle direction. If an input is unknown or approximate, the chart should retain that uncertainty instead of inventing precision.
At a glance
- Required date
- Recorded year, month and day with calendar type
- Required time
- Local clock time plus precision or uncertainty
- Required place
- Birth location sufficient to resolve zone and longitude
- Preserve
- Original record before any conversion
- Optional context
- Source document, recorder and confidence
- Not a pillar input
- Name, personality claims or desired outcome
Date, clock time and birthplace form the minimum calculation input
The date must identify whether it is Gregorian or Chinese-calendar input. A Chinese-calendar date also needs its leap-month flag, because the same month number can occur twice in one year.
The clock time must be the time written or remembered at the birthplace. The place should be specific enough to select the correct historical time-zone region and, when enabled, the longitude used for solar-time correction.
- Record the calendar before converting it.
- Use the birthplace, not the reader’s current location.
Keep source data separate from normalized calculation data
A birth certificate, hospital record or family note may use a local legal clock that later changed. Store that original wording first, then derive the UTC instant, solar time and Four Pillars as separate fields.
This separation makes later corrections auditable. A newly discovered time-zone rule can update the derived chart without rewriting what the source actually said.
- Never overwrite the original date and time.
- Attach source and confidence where available.
Approximate or missing input must remain visible
“Around dawn,” a rounded hour and a completely unknown birth time are different evidence states. Convert each into an explicit range or missing value rather than a fabricated minute.
If the possible interval crosses a pillar boundary, compare the distinct candidate charts and label which conclusions remain stable. If it does not cross a boundary, report that the uncertainty did not alter the pillars.
- Preserve the stated precision.
- Do not default an unknown hour to noon.
Separate pillar calculation from later interpretive settings
The Four Pillars come from the normalized birth instant and the declared calendar rules. A person’s name, occupation, desired answer or reported life events must not alter those deterministic symbols.
Some traditions use sex or another declared rule when choosing luck-cycle direction. That is a downstream method setting and should be documented separately from the birth data required to calculate the natal pillars.
- Calculate first; interpret second.
- Name every downstream doctrine that changes results.
Sources and editorial basis
- IANA Time Zone DatabaseIANA 依代表地點維護歷史民用時間規則；出生地點與日期是還原出生瞬間的必要輸入The maintained reference for historical local-time rules, UTC offsets, and daylight-saving transitions by location.
- Hong Kong Observatory: The Chinese Agricultural Calendar香港天文台曆表與中國農曆說明提供公曆、農曆、閏月與干支日對照，曆法種類與閏月標記不可省略An official overview of how the Chinese agricultural calendar combines solar and lunar cycles, including months, leap months, and solar terms.
- OpenFate Editorial Methodology產品分開保存原始出生紀錄、日曆轉換、歷史時區、太陽時設定與日界；缺失時辰為 null，不補造分鐘OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.