Deriving Luck Cycles

bazi · method · BaZi · Luck-Cycle Derivation Method

Purpose

After four pillars are fixed, produce the roughly decade-long luck-cycle stem–branch sequence and each step’s start/end age (or years) for stacking with annual pillars.

Concept: Luck Cycle; forward/reverse rule of thumb: Luck Cycle Forward/Reverse.

Prerequisites

Four-Pillar Charting completed
Sex known
Times of neighboring “jie” solar terms before/after birth known (for start-day count)

Step 1: Forward or reverse

Common rule (state which school you adopt in the result):

Year stem yang: male forward, female reverse
Year stem yin: male reverse, female forward

Forward: from the month pillar, take subsequent Jiazi pairs; reverse: take prior pairs. Each step is one stem–branch pair; usually arrange several consecutive steps (e.g. 8–10) to cover a lifetime.

Step 2: Starting age

If forward: count days from birthday to the next jie.
If reverse: count days from birthday to the previous jie.
Traditional conversion: about 3 days ≈ 1 year (finer schools convert hours to months). Obtain “age when luck starts.”
When start is under one year or very near a term change, keep the raw day count; avoid rounding that hides error.

Step 3: Arrange luck cycles

From the month pillar, take the next (or previous) stem–branch pair as the first luck step.
Each step covers about ten years; handover year can use “start age + 10×(n−1)” against the Gregorian calendar.
Output table should include: step index, stem–branch, start age, end age (or start/end years).

Step 4: Link to annual pillars

Luck cycles supply the ten-year background; Annual Pillar supplies that year’s stem–branch. First fix “which luck step we are in,” then take that year’s stem–branch—do not read the annual alone.

Full reading order: Chart Deduction and Reading Order.

Boundaries

Different almanacs may differ by minutes at solar terms; borderline charts can shift starting age.
Fix and state whether ages use nominal (xu) or full (zhou) years.
Some schools refine start conversion further; conclusions follow the declared algorithm.