The Bazi Synastry Scoring Algorithm: A Technical Deep Dive

Introduction

This document details the proprietary scoring logic used in our Bazi (Four Pillars of Destiny / Bāzì 八字) Synastry Engine. Unlike generic zodiac matching which relies solely on the Year Branch (East/West Group), our engine implements a multi-dimensional analysis rooted in classical methodology found in texts like Dī Tiān Suǐ (Dripping Heaven Essence / 滴天髓) and Sān Mìng Tōng Huì (Three Lives United / 三命通會).

The final compatibility score (0-100) is a weighted composite of five distinct layers of the chart, prioritized by their impact on long-term cohabitation and shared destiny.

The Formula Overview

Component	Weight	Classical Basis
1. Day Master Reciprocity	25%	Rì Zhǔ (Day Master / 日主) represents the Self and the Soul.
2. Spouse Palace Wiring	20%	Rì Zhī (Day Branch / 日支) is the literal "Palace of the Spouse."
3. The 4 Pillars Alignment	30%	Structural compatibility across distinct life domains (Year/Month/Hour).
4. Elemental Balance	15%	Yòng Shén (Useful God / 用神) theory — finding balance through the partner.
5. Karmic Hidden Bonds	10%	Cáng Gān (Hidden Stems / 藏干) revealing subconscious attachments.

1. Day Master Reciprocity (25%)

Concept: The Day Master (Day Stem) is the reference point for the entire chart. Synastry begins by asking: How does my core energy interact with yours?

Scoring Logic

We look for specific interaction patterns defined in the Shí Gān (Ten Stems / 十干) theory.

Combination (Hé / 合) - 95 Points: The highest form of fated attraction.
- Reference: Sān Mìng Tōng Huì describes these as "Attraction of Opposites" (Yang merges with Yin).
- Example: Yang Wood (Jiǎ / 甲) combines with Yin Earth (Jǐ / 己). The strong, upright tree (Jiǎ) finds stability in the soft, nurturing soil (Jǐ).
Production (Shēng / 生) - 85 Points: The "Giver-Receiver" dynamic.
- Reference: Dī Tiān Suǐ emphasizes flow.
- Example: Yin Water (Guǐ / 癸) produces Yang Wood (Jiǎ / 甲). The gentle rain (Guǐ) nourishes the tree. This is a supportive, nurturing bond.
Clash (Chōng / 沖) - 40 Points: Direct opposition.
- Example: Yang Metal (Gēng / 庚) clashes with Yang Wood (Jiǎ / 甲). The Axe chops the Wood. This indicates high passion/chemistry but inevitable friction and arguments.

2. Spouse Palace Wiring (20%)

Concept: The Earthly Branch of the Day Pillar is the "Palace" where the partner "sits." This determines domestic safety and intimate behavior.

Scoring Logic

We map the interaction between Partner A's Day Branch and Partner B's Day Branch.

Six Harmony (Liù Hé / 六合) - +15 Points: Emotional stability.
- Example: Horse (Wǔ / 午) and Goat (Wèi / 未). These two Fire/Earth branches merge seamlessly, indicating a couple that feels "at home" with each other instantly.
Punishment (Xíng / 刑) - -12 Points: Internalized stress or karmic lessons.
- Source: Yuān Hǎi Zǐ Píng (淵海子平). Punishments often manifest as "doing the wrong thing for the right reason."
- Example: Rat (Zǐ / 子) and Rabbit (Mǎo / 卯) form an "Uncivilized Punishment" (Wú Lǐ Xíng / 無禮刑). This often manifests as sexual tension followed by disrespect or boundary issues.
Clash (Chōng / 沖) - -15 Points: Instability.
- Example: Snake (Sì / 巳) vs Pig (Hài / 亥). Fire vs Water. A couple that is constantly moving, arguing, or triggering each other's fight-or-flight response.

3. The 4 Pillars Alignment (30%)

Concept: A relationship exists in four dimensions: Social (Year), Career/Parents (Month), Self/Spouse (Day), and Ambition/Children (Hour).

Hierarchical Weighting

We strictly weight the pillars based on their proximity to the "Self" (Day Master), a technique advocated by modern masters like Joey Yap and older lineages alike.

Day Pillar (40%): The Relationship Core.
Month Pillar (30%): The "Season" of the chart. Governs temperament and career. A Month Clash often means partners handle stress in opposite ways.
Hour Pillar (20%): Investment and children.
Year Pillar (10%): Least personal. External network.

Example Scenario

Year: Rat vs Horse (Clash). Interpretation: You dislike each other's friends or come from different social backgrounds. (Low impact).
Month: Tiger vs Pig (Harmony). Interpretation: You support each other's careers and emotional regulation. (High impact).

4. Evaluative Supply (The "Useful God") (15%)

Concept: This is the most sophisticated part of the engine, based on Yòng Shén (Useful God / 用神) theory. It's not enough to be "compatible"; you must be useful to each other.

The Logic Steps

Identify the Weakness: We calculate the weakest element in Chart A (e.g., Fire is 0%).
Check Partner's Inventory: Does Chart B have an abundance of Fire (>30%)?
Calculate Reciprocity:
- Case A (Ideal): Person A lacks Fire; Person B is 60% Fire. (+15 Points). Person B naturally warms up Person A.
- Case B (The Drain): Person A lacks Fire; Person B is also 0% Fire. (-5 Points). "Two blind people leading each other." Neither can provide the warmth needed.
- Case C (Asymmetry): Person A feeds Person B's Metal need, but Person B provides nothing for Person A's Fire need. Flagged as "Giver-Receiver Imbalance".

5. Karmic Hidden Bonds (10%)

Concept: Beneath every Earthly Branch lies "Hidden Stems" (Cáng Gān / 藏干). These represent the subconscious.

Scoring Logic

We scan for Hidden Combinations.

Example: Person A's Day Master is Yang Earth (Wù / 戊).
Person B has a Rat branch. The Rat contains hidden Yin Water (Guǐ / 癸).
Interaction: Wù + Guǐ is a Fire combination.
Result: Person A feels an inexplicable attraction to Person B, originating from a subconscious layer (the Branch) to the conscious self (Day Master). This explains "love at first sight" relationships that don't make logical sense.

Summary of Sources

Dī Tiān Suǐ (Dripping Heaven Essence / 滴天髓): The primary source for "Flow" and "Useful God" logic.
Sān Mìng Tōng Huì (Three Lives United / 三命通會): The encyclopedic reference for Shen Sha (Stars) and detailed interaction lists (Punishments/Harms).
Zǐ Píng Zhēn Quán (True Interpretation of Zi Ping / 子平真詮): Used for structure analysis and Ten Gods interpretation.