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Bazi calculation foundations

Bazi Calendar and Pillar Calculation

Learn how calendar dates, solar terms, Li Chun, month boundaries, and the Five Tigers and Five Rats rules determine the Four Pillars.

Editorially reviewed:

Overview

A Bazi chart starts with one normalized moment, then applies explicit year, month, day, and hour boundary rules. Lunar dates and civil calendar labels are useful references, but they do not replace solar-term and sexagenary-cycle calculation.

At a glance

Catalog
Calendar and Pillar Calculation
Catalog entries
53 reference entries
Reading role
This category separates date representation, solar-term boundaries, year and month conventions, and the deterministic rules used to derive each pillar.
Evidence standard
A reproducible result records the input instant, location or time zone, boundary convention, ephemeris or calendar source, and the rule used for every pillar.
Interpretive boundary
Do not infer a month pillar from a lunar month number, switch a Bazi year at Lunar New Year without naming that convention, or treat an approximate solar-term date as the exact boundary instant.

Explore concepts

What the Calendar and Pillar Calculation catalog covers

This category separates date representation, solar-term boundaries, year and month conventions, and the deterministic rules used to derive each pillar.

This hub organizes 53 indexed topics under one editorial model so definitions, derivations, interpretation order, and limits remain consistent across the catalog.

  • Begin with the definition before using an interpretive keyword.
  • Keep the named concept connected to stems, branches, season, placement, and the complete chart.

How to use the topic index

Every Calendar and Pillar Calculation entry preserves its workbook name and Chinese term, then places it inside a smaller conceptual group for easier comparison.

Use neighboring entries to compare similar rules, but verify each page independently because a shared family name does not make two concepts interchangeable.

  • Search by English title, simplified term, traditional term, or a common alias.
  • Follow related concepts when a rule depends on another part of the Bazi system.

A disciplined reading sequence

Normalize the recorded time and time zone first, resolve exact solar-term instants, state the day-boundary convention, and only then calculate the stem-branch pairs.

Record the observed chart facts first, then state the rule being applied, and only afterward form a bounded interpretation. This separates calculation from judgment.

  • Confirm the input, lookup anchor, and chart position before interpreting.
  • Check whether season, strength, combinations, and timing support or weaken the proposed reading.

Evidence, school differences, and limits

A reproducible result records the input instant, location or time zone, boundary convention, ephemeris or calendar source, and the rule used for every pillar.

Do not infer a month pillar from a lunar month number, switch a Bazi year at Lunar New Year without naming that convention, or treat an approximate solar-term date as the exact boundary instant.

  • Treat named rules as evidence with a stated scope, not as automatic life-event predictions.
  • When traditions differ, identify the convention instead of blending incompatible thresholds.

Sources and editorial basis

  1. Hong Kong Observatory: The Chinese Agricultural Calendar
    An official overview of how the Chinese agricultural calendar combines solar and lunar cycles, including months, leap months, and solar terms.
  2. Hong Kong Observatory: The 24 Solar Terms
    An official astronomical explanation of the 24 solar terms, their 15-degree divisions along the ecliptic, and the alternating major and minor terms.
  3. Hong Kong Observatory: Heavenly Stems and Earthly Branches
    An official modern reference for the canonical stem and branch orders, the sexagenary cycle, and calendrical use.
  4. 《三命通會》 (Sanming Tonghui)
    A historical compilation covering stems and branches, Ten Gods, Nayin, Shen Sha, and multiple classical pattern systems.
  5. OpenFate Editorial Methodology
    OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.

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