Births Near an Hour Boundary in Bazi
Calculate births near a two-hour boundary by resolving time-zone and solar-time settings before comparing the possible Hour Pillars.
Overview
The twelve Bazi hour branches are assigned to consecutive two-hour intervals, so a birth near a boundary can move from one Hour Branch to the next after time-zone, longitude or equation-of-time correction. The correct response is not to round the clock or choose the more appealing chart. Resolve the source interval using one declared time model, test the corrected interval against the exact branch boundary, and preserve each distinct candidate. Because the Hour Stem depends on the effective Day Stem, a simultaneous day-boundary crossing requires the entire Hour Pillar to be recalculated.
At a glance
- Hour structure
- 12 consecutive two-hour branch intervals
- Required basis
- Declared civil or solar-time method
- Possible change
- Hour Branch and Hour Stem
- Extra boundary
- Day rollover near Zi hour
- Safe result
- Distinct candidates with their time ranges
- Unsafe method
- Rounding or choosing by interpretation
Resolve the time basis before assigning an hour branch
A written civil time is first interpreted through its historical zone. Apply longitude and equation-of-time corrections only if the chart method explicitly uses them.
Comparing an uncorrected time in one candidate with a solar-corrected time in another creates a false difference. All candidates must share the same birthplace, source record and settings.
- Use one time model for every candidate.
- Keep civil and corrected readings visible.
Test the full uncertainty interval against the exact cutoff
Represent “about 09:00” or a rounded certificate as an interval supported by the source. Transform both ends and identify which portion belongs to each hour branch.
If the complete interval remains on one side, the Hour Branch is stable. If it straddles the cutoff, retain both outcomes rather than collapsing them to the midpoint.
- Do not test only the displayed minute.
- State the interval assigned to each branch.
Recalculate the Hour Stem from the effective Day Stem
Moving to the next branch changes the Hour Branch directly. Near the chart’s day boundary, the effective Day Stem may also change, which changes the Five Rats starting stem used for the hour.
A safe calculator derives the whole Hour Pillar from the resolved candidate timestamp. It never swaps only the branch label or carries an hour stem from the other day.
- Recompute stem and branch together.
- Apply the saved day-boundary convention.
Treat the result as input sensitivity, not two personalities
Candidate charts describe what the calculation does under unresolved time evidence. They do not prove that a person has two identities or that the boundary itself predicts instability.
Compare only the fields that differ and keep common evidence once. If later records narrow the interval, the audit trail should show why one candidate was retired.
- Separate shared from candidate-only findings.
- Keep correction evidence with the decision.
Sources and editorial basis
- Hong Kong Observatory: Heavenly Stems and Earthly Branches香港天文台列出十二地支標準次序與干支紀時基礎，作為時支區間與時柱推導的現代官方參考An official modern reference for the canonical stem and branch orders, the sexagenary cycle, and calendrical use.
- IANA Time Zone Database候選時間先以同一出生地歷史時區轉為有效瞬間，避免不同偏移或重複鐘點製造假的時辰差異The maintained reference for historical local-time rules, UTC offsets, and daylight-saving transitions by location.
- OpenFate Editorial Methodology產品以完整不確定範圍測試邊界，差異候選採相同設定重算完整時柱，且不依解讀感受選盤OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.