# Method — Tian Mira BaZi Calculation Engine

## Input Data

Birth data records are sourced from:
- Astro-Databank official C sample (3,604 records, Rodden Rating AA)
- VedAstro 15k dataset (14,554 records, Rodden Rating AA claimed)

## Calculation Pipeline

1. **Timezone Resolution**: Historical timezone determined via GeoNames city index
   and coordinate lookup.
2. **True Solar Time**: Longitude correction + Equation of Time applied to local
   birth time to compute apparent solar time.
3. **Four Pillars (BaZi)**: Year, Month, Day, and Hour pillars computed using
   the solar calendar (Jie Qi) with Heavenly Stems and Earthly Branches.
4. **Day Master**: The Heavenly Stem of the Day Pillar.
5. **Hidden Stems**: Branch-hidden Heavenly Stems with Qi quality classification.
6. **Ten Gods**: Relationships between Day Master and all other stems.
7. **Na Yin**: Melodic Element of each pillar pair.
8. **Five Elements**: Element distribution analysis.
9. **Advanced Weighting V2**: Normalized weighted scores accounting for
   combination strength, season, stem-branch interactions, and hidden stems.
   Outputs: percentages (wood, fire, earth, metal, water), conclusion,
   confidence score, favorable/unfavorable/neutral elements.
10. **Luck Cycles**: 10-year luck pillars with Liu Nian (annual) and Liu Yue
    (monthly) influences.

## Interpretation

**This dataset contains NO interpretation, prediction, or narrative output.**
All outputs are purely technical calculations.

## Version

Engine: Tian Mira BaZi calculation engine
Method: advanced_v2
Date: 2026-06-19