Unknown Birth Hour in Bazi
See what a Bazi chart can still calculate without a birth hour, which readings must be withheld, and when a candidate or rectification workflow helps.
Overview
If the birth hour is unknown, do not default to noon or fabricate an Hour Pillar. With a reliable date and place, the Year, Month and Day Pillars can often still be calculated under declared boundary rules, but hour-based relations, some timing details and any conclusions that depend on the Hour Pillar must remain unavailable. OpenFate should label the chart as three-pillar or unknown-hour, then offer broad candidate comparison or optional rectification without promising recovery.
At a glance
- Do not do
- Default silently to noon or midnight
- Often available
- Year, Month and Day Pillars from reliable inputs
- Unavailable
- Confirmed Hour Pillar and hour-dependent relations
- Display status
- Unknown-hour or three-pillar chart
- Optional workflow
- Candidate ranges or rectification
- Boundary
- No promise to reconstruct the exact time
Calculate only the pillars supported by the record
A known date and birthplace can support Year, Month and Day calculations once calendar, zone and day-boundary assumptions are clear. The Hour Pillar has no evidence and should be null.
Showing an invented pillar makes downstream relations look deterministic. An explicit blank is more useful because readers can see which evidence is missing.
- Keep the Hour Pillar empty.
- Label all calculations that remain convention-sensitive.
Suppress interpretations that require the Hour Pillar
Ten-God relations, hidden stems, interactions and palace symbolism involving the hour cannot be confirmed. Timing methods that use the hour also need to be withheld or marked conditional.
The other three pillars are not invalidated, but their reading must not quietly borrow hour-dependent claims from a complete-chart template.
- Gate every claim by required inputs.
- Do not average all twelve hours into one result.
Candidate comparison can show what remains stable
The system can calculate twelve branch-hour candidates, or fewer distinct charts after day-boundary handling, and summarize the findings shared by all of them.
If family records narrow the range, use only those supported intervals. A rectification workflow is optional and should keep lower-ranked candidates visible.
- Compare unique candidates transparently.
- Use evidence to narrow, not intuition alone.
Missing time is not a defect to hide
Many historical or family records simply do not preserve an exact hour. The product should remain useful without pressuring a user to guess.
No inferred hour should become medical, financial, legal or relationship evidence. The saved chart must continue to show that the source hour is unknown.
- Normalize uncertainty as a valid state.
- Never present an estimate as the original record.
Sources and editorial basis
- Hong Kong Observatory: Heavenly Stems and Earthly Branches香港天文台天干地支次序支持已知年、月、日的干支表示；沒有出生時刻便沒有可驗證的時支與時干輸入An official modern reference for the canonical stem and branch orders, the sexagenary cycle, and calendrical use.
- 《三命通會》 (Sanming Tonghui)《三命通會》日上起時法以已知日干及時支推時干，規則本身不能從未知時刻反推出唯一時柱A historical compilation covering stems and branches, Ten Gods, Nayin, Shen Sha, and multiple classical pattern systems.
- OpenFate Editorial Methodology產品把未知時辰保存為 null，不以正午或午夜填補；只發布不依賴時柱的資訊，時柱相關內容標示為缺失或條件式OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.