How to Calculate Luck-Pillar Start Time
Calculate the first Luck-Pillar start time from a verified birth instant, direction-selected solar term, exact elapsed interval, and documented conversion rule.
Overview
To calculate a Luck-Pillar start time, establish the precise birth instant in its historical time zone, determine direction, select the next or previous applicable solar term, measure the exact interval, and convert it under the chosen traditional ratio. Add that converted duration to birth to obtain a civil start date. The calculation should expose year, month, and day components and never substitute a rounded age for the dated boundary.
At a glance
- Time basis
- Historical local birth instant
- Direction
- Forward or reverse
- Reference
- Next or previous solar term
- Raw measure
- Elapsed days and hours
- Final output
- Civil start date
- Audit
- Versioned calendar method
Normalize the birth instant without losing provenance
Resolve the entered place to its historical time zone and retain the original civil time, offset, and any declared true-solar-time option.
Do not silently reinterpret daylight saving time or replace an unknown location with a default city.
- Keep civil and derived times separate.
- Record the time-zone source and options.
Select the correct solar-term instant
After direction is fixed, choose the relevant future or prior solar-term boundary required by the calculation convention.
Use an ephemeris instant rather than a date-only almanac label because hours near the boundary materially change the elapsed interval.
- Store the term name and timestamp.
- Use the same ephemeris across locales.
Convert the exact interval under one rule
Measure elapsed time first, then apply the documented days-to-years and smaller-unit conversion. Do not round before the final display step.
Adding the converted duration to birth yields the first start date; each following Luck Pillar boundary comes from the calculated period sequence.
- Convert after measuring exact duration.
- Persist the unrounded calculation result.
Protect deterministic parity and frozen reports
Test known forward and reverse examples, solar-term edge cases, leap years, historical offsets, and locale formatting without changing the absolute instant.
If the library or ephemeris changes, issue a versioned methodology update and preserve prior user reports rather than retroactively moving their boundaries.
- Use fixtures for calendar edges.
- Never mutate purchased historical reports.
Sources and editorial basis
- 《三命通會》 (Sanming Tonghui)《三命通會》卷二「論大運」按順逆量取生後未來或生前過去節氣，並以日數折算起運A historical compilation covering stems and branches, Ten Gods, Nayin, Shen Sha, and multiple classical pattern systems.
- 《淵海子平》 (Yuanhai Ziping)《淵海子平》起運法：節氣距離是換算輸入，須先定月柱與方向再求起點A foundational Ziping reference for branch months, hidden stems, roots, and stem-branch relationships.
- OpenFate Editorial Methodology起運時間頁保存歷史時區、節氣時間戳、未取整間隔、startYear/startMonth/startDay 與算法版本OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.