Calculation register · P0
Every chart keeps its method attached.
MingWeave calculates Four Pillars deterministically in the browser. This page names the inputs, datasets, conventions, boundaries, and uncertainty rules behind the current engine.
Defaults are choices, not hidden truths.
Which birth inputs does MingWeave use?
The engine receives a Gregorian birth date, a known local clock time or an explicit unknown-time state, a resolved birthplace with latitude, longitude, and IANA time zone, a traditional Luck Pillar calculation category, and one approved Method Profile.
The place query and chart are held in browser memory. A known-time calculation also requires an explicit choice when a daylight-saving clock label occurred twice. No name, email, account, or free-text biography is needed.
Why is birthplace required?
Place resolves the historical time-zone rules needed to turn a local clock record into a physical UTC instant. It also supplies longitude for optional Local Apparent Solar Time. Latitude supports place confirmation and audit but does not enter the P0 solar-time offset.
The bundled city search works locally. If a locality is absent, manual entry preserves the same required fields and marks the reduced coordinate precision in the result.
How are IANA time zones and DST handled?
MingWeave uses versioned IANA time-zone data rather than assuming today’s offset. The engine enumerates valid instants for a local clock. One candidate is normal, two candidates require a first-or-second occurrence choice, and zero candidates identify a nonexistent spring-forward time.
Historical sub-minute offsets and pre-1970 uncertainty produce warnings. A modern UTC-offset lookup is not silently substituted for the historical zone.
What is True Solar Time, and is it enabled by default?
It is Local Apparent Solar Time. The engine converts the resolved UTC instant to Local Mean Solar Time with utcMinutes + 4 × longitudeDegrees, then adds the versioned NOAA-style equation-of-time approximation mw-eot-noaa-v1.
It is off by default. When enabled, it affects the working date used for the Day Pillar and the clock used for the Hour Pillar. It does not alter the physical birth instant or move Year and Month solar-term boundaries.
Why does the Year Pillar change at Li Chun?
This is MingWeave’s declared Four Pillars convention. The engine compares the physical birth instant with the exact Li Chun solar-term instant. At the boundary the new sexagenary year begins; January 1 and Lunar New Year are not used as substitutes.
A known birth within thirty minutes produces a solar-term warning. If Li Chun occurs during a date with unknown birth time, the engine returns the possible Year Pillars instead of choosing one.
Which solar-term boundaries define the Month Pillar?
The twelve monthly Jie are Li Chun, Jing Zhe, Qing Ming, Li Xia, Mang Zhong, Xiao Shu, Li Qiu, Bai Lu, Han Lu, Li Dong, Da Xue, and Xiao Han. The latest Jie at or before the birth instant selects the month ordinal and branch.
The comparison uses exact UTC instants from the versioned solar-term dataset. Gregorian month starts, Lunar month starts, and date-only solar-term labels are not used.
How do midnight and Zi-hour Day Pillar rules differ?
The standard profile advances the effective date at civil midnight. The Zi-start profiles advance it at 23:00. Their Day Pillars differ only when the selected civil or apparent-solar clock lies from 23:00 through 23:59.
The Hour Stem is derived from the effective Day Stem, so it can change too. The Hour Branch remains Zi throughout 23:00–00:59. Profile comparison keeps the birth input fixed and highlights the changed pillars.
How are Luck Pillar direction and starting age calculated?
Direction combines Year Stem polarity with the selected traditional category: male with Yang or female with Yin proceeds forward; male with Yin or female with Yang proceeds backward. “Compare both” returns both sequences. Each sequence moves from the Month Pillar through eight sexagenary steps.
Forward measures to the next monthly Jie; backward measures to the previous one, using actual UTC duration. Three real days equal one age year, one day equals four age months, and one hour equals five age days. The result preserves decimal age, normalized years-months-days, and an approximate local start date.
What are the limits of the Five Elements quantity?
P0 uses the versioned visible-and-hidden-unweighted-v1 structural model across visible pillars and the approved Hidden Stem table. The distribution makes its included components auditable but is not a scientific measurement or a complete traditional strength analysis.
Season, rooting, interactions, transformation conventions, and school-specific weights can support additional interpretations. MingWeave does not convert the displayed quantity into a diagnosis, remedy, or deterministic verdict.
Which rules are data, and which are project conventions?
Astronomical and civil-time inputs include solar-term instants and IANA time-zone transitions. Deterministic mappings include the sexagenary cycle, Hidden Stems, Ten Gods, and interaction tables. Project conventions include the default time basis, day boundary, Luck direction rule, starting-age ratio, Five Element model, and warning thresholds.
Traditional interpretations sit above those layers and are written as bounded cultural prompts. AI is never permitted to calculate pillars, solar terms, Hidden Stems, Ten Gods, elements, or Luck Pillars. The learning library keeps these evidence types visible in each public guide.
How are the engine, datasets, and profile versioned?
Current results record engine 1.0.0, Method Profile version 1.0.0, time-zone data 2026c, solar terms 1900–2101 v1, and the versioned location index. The trace also identifies the day-cycle anchor and equation-of-time model.
A public calculation change requires a rules-document review, a version decision, and independently reviewed golden tests. A display-only release cannot silently change these outputs.
How can I report a calculation difference or bug?
Share only the minimum evidence you are comfortable providing: the differing pillars, Method Profile ID, engine and dataset versions, warning codes, and the other calculator’s stated rules. Do not post a private birth record publicly.
The current P0 site does not provide an account or support upload. Until a dedicated privacy-reviewed contact route exists, preserve the sanitized copied summary and the relevant trace labels. Review the Privacy Policy before sending data through any future channel.