Zi Wei Methodology
Exactly how our Zi Wei Dou Shu engine calculates — every conversion step, every convention we follow, and where interpretation begins.
1. The Calculation Pipeline
Every chart is computed by a deterministic pipeline. No AI generates your palaces; no randomness enters the star placements. Each step is locked by our regression suite:
- Solar → Lunar conversion. Your Gregorian birth date converts to the Chinese lunar calendar (year, month, day, leap-month flag) using an astronomical calendar engine, not a lookup table copied from another site.
- Hour → Shichen (时辰). Birth time maps to one of 12 double-hours. The late-Zi boundary (23:00) follows a documented convention (see §2).
- Leap-month normalization. Leap months use the split convention: the first half belongs to the leap month itself, the second half rolls into the following month (except late-Zi births, which skip the split — verified against three historical test charts).
- Ming / Shen palace placement. The Soul Palace (命宫) counts backwards from the month palace by the birth hour; the Body Palace (身宫) counts forwards. Both derive from the lunar month and shichen — pure integer arithmetic.
- Wu Xing Ju (五行局). The Five-Element class of the Soul Palace's stem-branch pair (via NaYin) determines the starting age of the first decadal luck period (2 for Water, 3 for Wood, 4 for Metal, 5 for Earth, 6 for Fire).
- Star placement (安星). All 14 major stars, plus auxiliary stars, are placed by classical formulae: Zi Wei by the 66-entry commercial algorithm on the astro-day, Tian Fu by mirror symmetry across the Yin–Shen axis, day-stars by birth hour, year-stars by year stem/branch.
- Four Transformations (四化). Lu, Quan, Ke, Ji are derived from the year stem alone — a 10×4 lookup that is invariant across all schools.
- Decadal luck (大限). Yang-male/Yin-female run clockwise from the Soul Palace; Yin-male/Yang-female counter-clockwise. Each decade spans 10 virtual years starting from the Wu Xing Ju age.
2. Conventions We Follow
Where schools differ, we publish which convention we use, why, and who else uses it — so you can compare apples to apples.
2.5 Interpretation Layer — Rules Under Test
The interpretive rules below are not free-form AI text. Each is a deterministic scoring rule with a published case in our regression suite — if a future change breaks one, deployment is blocked.
- YL Four-Laws (mathematical invariants). Chang–Qu / Kong–Jie placements across 13 hours; Lu–Yang–Tuo triplets across 10 stems; Si Hua mapping across 10 stems; major-star placement across 500 charts. These are structural theorems — every chart must satisfy them.
- Palace brightness (庙旺利陷). Star brightness by palace branch follows the 72-cell classical matrix, verified cell by cell.
- Golden corpus. 10,940 random charts plus 940 edge cases are compared field-by-field (75 fields per chart) against the independent iztro benchmark — 820,500 assertions, all green.
3. Where Calculation Ends and Interpretation Begins
The pipeline above is deterministic and verifiable: given the same birth data, any correctly implemented engine returns the same chart. What the chart means — career aptitude, relationship dynamics, timing of fortune — is interpretation. Interpretation draws on classical texts (Zi Wei Dou Shu Quan Shu, Zhai Xiang Bao Zhao) and modern practice; different schools read the same chart differently. We distinguish the two explicitly:
- Calculation (verifiable): palace layout, star positions, brightness, Four Transformations, decadal ranges. Locked by 835,000+ assertions. Verify it yourself →
- Interpretation (methodology-stated): personality archetypes, palace meanings, star combination readings. Follows the Quan Shu mainstream; cross-school differences are flagged inline rather than silently resolved.