Solar-Term Depth in Bazi (節氣深淺)
Learn how solar-term depth measures a birth moment within a seasonal segment, which time inputs are required, and why hidden-stem day tables vary by method.
Overview
Solar-Term Depth (節氣深淺) places the birth instant between relevant solar-term boundaries. It can be expressed as elapsed time, a normalized fraction, or a school-specific hidden-qi stage. Correct calculation requires an exact timestamp, time zone, historical offset, and exact term instants. Traditional day-allocation tables are interpretive conventions; they should not be presented as a single universal astronomical formula.
At a glance
- Input
- Exact birth instant and location-aware time zone
- Boundaries
- Exact neighboring solar-term instants
- Output
- Elapsed duration or normalized position
- Possible use
- Hidden-qi staging and seasonal weighting
- Variation
- Day-allocation tables differ by school
- Limit
- A model parameter, not a life-event timer
Resolve the birth instant before measuring depth
Normalize the recorded local time using the correct IANA time zone and historical offset. Apply true solar time only if the chosen chart policy explicitly requires it.
Fetch or calculate the exact solar-term instants around that normalized birth moment. Calendar dates alone are too coarse near a boundary.
- Preserve the original and normalized time.
- Use exact term timestamps.
Measure position within the declared segment
A transparent engine can report time since the previous term, time until the next term, and their ratio. The denominator and term pair must be named.
If the method instead divides the month into fixed hidden-stem days, publish that table and how partial days are handled.
- Expose the interval formula.
- Version school-specific day tables.
Use depth to refine, not replace, seasonal evidence
Depth can distinguish residual qi near a transition from the more settled qi later in a segment. It should refine the Month Branch reading rather than create an independent pillar.
Roots, exposure, interactions, and whole-chart momentum can confirm or oppose the seasonal refinement.
- Treat depth as a modifier.
- Rejoin the whole-chart audit.
State precision and uncertainty honestly
Unknown minutes, uncertain birthplace, historical time-zone ambiguity, or disputed solar-time policy can move the calculated depth. Report that sensitivity.
Do not use a fractional depth score to predict exact dates, medical outcomes, or deterministic personality traits.
- Carry input uncertainty forward.
- No false precision from decimals.
Sources and editorial basis
- 《三命通會》 (Sanming Tonghui)《三命通會》按節候先後與月中氣勢深淺分析旺衰，顯示同一月支仍須區分節內位置A historical compilation covering stems and branches, Ten Gods, Nayin, Shen Sha, and multiple classical pattern systems.
- 《子平真詮》 (True Explanations of Ziping)《子平真詮》月令論法重視節氣交接、透藏及氣勢是否已定，不把民用月份代替精確節入A major reference for month-command, structure, and contextual Bazi interpretation.
- OpenFate Editorial Methodology節氣深淺頁保留原始時間、IANA時區、歷史偏移與精確節入，分日表另行版本化並揭露邊界不確定性OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.