Basic Structure of the Four Pillars (四柱八字)
See how four pillars, eight visible characters, hidden stems, the Day Master, month command, Ten Gods, and timing layers fit into one Bazi chart.
Overview
A Bazi chart has four ordered columns—Year, Month, Day, and Hour. Each column contains one Heavenly Stem above one Earthly Branch. The Day Stem supplies the Day Master reference, the Month Branch supplies the main seasonal frame, and hidden stems, Ten Gods, interactions, patterns, and luck cycles are derived layers that must remain traceable to those original eight characters.
At a glance
- Column order
- Year → Month → Day → Hour
- Top row
- Four Heavenly Stems
- Bottom row
- Four Earthly Branches
- Relational reference
- Day Stem
- Seasonal reference
- Month Branch
- Derived layers
- Hidden stems, Ten Gods, relations, patterns, and timing
Read the chart as an ordered two-row grid
The four columns preserve different time resolutions of one birth instant. Their order is fixed and affects positional interpretation.
The stem above and branch below belong to the same pillar, while cross-pillar relations connect symbols across columns. A display should never detach data from its pillar.
- Preserve Year–Month–Day–Hour order.
- Keep every stem paired with its own branch.
Day Master and month command have separate jobs
The Day Stem is the reference from which Ten Gods are assigned. It does not represent the entire person or override the other seven characters.
The Month Branch establishes the principal seasonal context. Seasonal command is primary evidence, but roots, support, drain, control, and transformation still matter.
- Calculate Ten Gods from the Day Stem.
- Assess season from the resolved Month Branch.
Derived fields must remain auditable
Hidden stems come from a canonical branch table; Ten Gods come from phase and polarity relative to the Day Master; interactions come from explicit pair or group rules.
Patterns, useful gods, and timing interpretations sit above those facts. If a lower-layer calculation changes, every dependent label must be recomputed.
- Store the rule behind each derived field.
- Do not hand-edit downstream labels.
More fields do not create more certainty
A richly annotated chart can still contain disputed school rules and uncertain birth data. Quantity of labels is not the same as quality of evidence.
Use the structure to organize a reading, disclose assumptions, and avoid turning one cell or one derived label into a total verdict.
- Show uncertainty at the affected layer.
- Require whole-chart support for conclusions.
Sources and editorial basis
- 《三命通會》 (Sanming Tonghui)《三命通會》四柱諸論：年月日時各以一干一支組成A historical compilation covering stems and branches, Ten Gods, Nayin, Shen Sha, and multiple classical pattern systems.
- Hong Kong Observatory: Heavenly Stems and Earthly Branches干支紀日與六十甲子說明：每柱干支對的結構基礎An official modern reference for the canonical stem and branch orders, the sexagenary cycle, and calendrical use.
- OpenFate Editorial Methodology四柱結構頁保留原始八字、藏干派生欄位與運勢時間層的差異OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.