What Is the Four Pillars System?
Bazi — literally "Eight Characters" — gets its name from its structure: four pillars, each composed of two Chinese characters.
The Four Pillars
Each pillar corresponds to one dimension of your birth moment:
| Pillar | Time Span | Common Reading Focus |
|---|---|---|
| Year Pillar | Birth year | Family background, early environment |
| Month Pillar | Birth month (solar term boundaries) | Career environment, formative years |
| Day Pillar | Birth day | The self — the Day Master |
| Hour Pillar | Birth hour (every 2 hours) | Inner world, later years, children |
Why "Eight Characters"?
Each pillar contains two characters: a Heavenly Stem on top and an Earthly Branch below. Four pillars × two characters each = eight characters total.
Year Month Day Hour
甲 丙 庚 壬 ← Heavenly Stems (top)
子 寅 午 申 ← Earthly Branches (bottom)
What It Actually Records
Bazi is a time-coordinate encoding system. Ancient scholars mapped the 60-year Stem-Branch cycle to astronomical calendars, creating a symbolic notation for any moment in time.
Two important technical notes:
- Month boundaries use solar terms, not the first day of the lunar month. Each solar term falls around the 6th–8th of the calendar month.
- The year changes at the Start of Spring (Lì Chūn), not at the Lunar New Year or January 1st.
Next Step
Now that you understand the scaffold, let's look at the symbols that fill each cell.