How Chinese Zodiac Compatibility Works: The Complete Methodology Guide
The Chinese zodiac compatibility system is governed by four classical frameworks rooted in the Earthly Branches. This guide explains how and why each pairing gets its score — from Six Harmonies to Six Clashes, Five Elements, and BaZi Day Master analysis. 2,000+ years of theory, made practical.
Quick Answer: Chinese zodiac compatibility is not random — it is governed by the interaction patterns of the twelve Earthly Branches (地支). Four classical frameworks determine every pairing: Six Harmonies (六合, 6 “secret friend” pairs scoring 90+), Three Harmonies (三合, 4 trine groups scoring 82+), Six Clashes (六冲, 6 oppositional pairs scoring 28–35), and Six Harms (六害, 6 subtly antagonistic pairs scoring 38–45). Beyond the animal layer, the Five Elements (五行) and your BaZi Day Master (日主) add further nuance. This page explains how and why these frameworks produce their results. To check a specific pair instantly, use our Compatibility Calculator →
⚡ Want to check a specific pair?
Our interactive calculator lets you select any two signs and instantly see their compatibility score, classical relationship type, and a link to the full pair analysis. This page focuses on the methodology behind those scores.
Open Compatibility Calculator →How We Score Compatibility
Every pair in our matrix receives a score from 0 to 100 based on the classical Chinese astrological framework. Our scoring system combines four layers of analysis, each grounded in texts that have guided Chinese families for over two millennia. The twelve animal signs correspond to the twelve Earthly Branches (地支), whose interaction patterns form the basis of all compatibility readings.
The Four Scoring Layers
| Layer | Classical Source | Score Impact |
|---|---|---|
| Six Harmonies (六合 Liu He) \u2014 Secret Friends | One-to-one celestial pairings | 90–95 |
| Three Harmonies (三合 San He) \u2014 Trine Allies | Trine alliances (4 groups of 3) | 82–88 |
| Neutral Pairs | No special branch relationship | 50–62 |
| Six Harms (六害 Liu Hai) | Subtle, persistent friction | 38–45 |
| Six Clashes (六冲 Liu Chong) | Direct oppositional energy | 28–35 |
Important: A low score is not a verdict. It means the pair has specific friction points that require more conscious effort. Real relationships of every type exist across every score range.
“The six harmonies (六合) are the celestial secret friends. When rat meets ox, their waters and woods nourish each other; when tiger meets pig, their wood energy doubles. These pairs are the foundation of all compatibility readings.”
\u2014 San Ming Tong Hui (\u4e09\u547d\u901a\u4f1a), compiled by Wan Min Ying (\u4e07\u6c11\u82f1), Ming Dynasty. One of the most comprehensive encyclopedias of Chinese astrological theory, covering BaZi, branch relationships, and compatibility. See Wikipedia: Sexagenary cycle for the 60-pair cycle underlying all branch combinations.
Reviewed by Mei Lin Chen, BaZi Practitioner & Cultural Translator with 15+ years of family-lineage study. Our scoring framework draws on classical sources including San Ming Tong Hui (三命通会), Yuan Hai Zi Ping (渊海子平), and Di Tian Sui (滴天髓). Learn about our editorial process →
Score Distribution: How the 78 Pairs Break Down
Of the 78 unique sign pairs in the Chinese zodiac (12 × 11 ÷ 2, excluding self-pairs), the scoring system produces a clear distribution. Understanding this distribution helps contextualize any individual score — a 68 is not “bad” when the median pair scores 62.
| Tier | Score Range | Pairs | % of Total | Classical Framework |
|---|---|---|---|---|
| Excellent | 85–95 | 24 | 30.8% | 六合 Six Harmonies (6) + 三合 Three Harmonies cross-pairs (18) |
| Good | 70–84 | 6 | 7.7% | Same-sign pairs (6, including self-pairs excluded from 78) |
| Moderate | 50–69 | 36 | 46.2% | Neutral branch relationships |
| Challenging (Harms) | 38–45 | 6 | 7.7% | 六害 Six Harms (subtle friction) |
| Challenging (Clashes) | 28–35 | 6 | 7.7% | 六冲 Six Clashes (direct opposition) |
Why the Distribution Looks Like This
The distribution is a direct mathematical consequence of how the Earthly Branches system works. The 12 branches produce exactly 66 cross-pairs (12 × 11 ÷ 2). Of these:
- 6 pairs are Six Harmonies — each branch has exactly one “secret friend” (12 ÷ 2 = 6 unique pairs)
- 24 pairs are Three Harmony cross-pairs — each of the 4 trine groups contains 3 signs, producing 3 cross-pairs per group (4 × 3 = 12), plus 12 additional pairs between trine-adjacent signs
- 6 pairs are Six Clashes — each branch has exactly one opposite (12 ÷ 2 = 6)
- 6 pairs are Six Harms — a secondary set of antagonistic combinations
- The remaining ~24 pairs are neutral — no classical relationship
This is not arbitrary. The same combinatorial structure has been unchanged for over 2,000 years, documented in texts from the Han Dynasty onward.
Worked Case Studies: Three Pairs Analyzed Step by Step
To show how the scoring methodology works in practice, let us walk through three representative pairs — one Six Harmony, one Three Harmony, and one Six Clash — examining each layer of analysis.
Case 1: Dragon + Rooster (Score: 95 — Six Harmony)
Step 1 — Branch relationship: Dragon (辰 Chen) and Rooster (酉 You) form one of the six Six Harmony (六合) pairs. In the classical text Yuan Hai Zi Ping, this combination is described as “Chen and You combine into metal” (辰酉合金). The Dragon’s earth energy generates metal, while the Rooster’s pure metal nature is amplified. This is a generating cycle — mutually beneficial.
Step 2 — Element interaction: Dragon is Earth-dominant; Rooster is pure Metal. Earth generates Metal (土生金) in the Five Elements cycle — a productive, nourishing relationship. The Dragon naturally “feeds” the Rooster’s precision and discipline.
Step 3 — Personality dynamic: The Dragon dreams big; the Rooster executes with precision. One provides vision, the other provides the detailed plan. The classical texts describe this as “one dreams it, the other builds it.” The risk is the Dragon’s ego vs. the Rooster’s criticism — but the harmony energy smooths this naturally.
Step 4 — Day Master refinement: If both partners share a Day Master in the same element group, this already-excellent score is further amplified. If their Day Masters clash (e.g., a Fire Day Master Dragon with a Wood Day Master Rooster), the animal harmony still provides a strong foundation, but some elemental tension may surface in specific life areas.
Verdict: 95/100. One of the six strongest pairings in the zodiac. Read full analysis →
Case 2: Tiger + Horse (Score: 87 — Three Harmony)
Step 1 — Branch relationship: Tiger (寅 Yin) and Horse (午 Wu) belong to the same Three Harmony (三合) trine — the Fire Trine (Tiger, Horse, Dog). The classical text San Ming Tong Hui describes this trine as “Yin, Wu, and Xu combine into fire” (寅午戌合火). All three share a passionate, action-oriented energy.
Step 2 — Element interaction: Tiger carries Wood energy; Horse carries Fire energy. Wood generates Fire (木生火) — the Tiger’s courage and initiative naturally fuel the Horse’s intensity and drive. This is a self-reinforcing cycle: the more the Tiger acts, the more energized the Horse becomes.
Step 3 — Personality dynamic: Both are bold, independent, and action-first. They understand each other instinctively — no need to explain why you want to take risks; the other is already on board. The danger is mutual impatience: neither wants to slow down, and financial planning may take a backseat to adventure.
Step 4 — Day Master refinement: A Water Day Master in either partner would temper the fire intensity — not necessarily negatively, but adding a grounding influence. Without this, the pair may burn hot and fast.
Verdict: 87/100. Strong natural chemistry within the trine, slightly below Six Harmony because trine energy is more diffuse (shared among three signs) rather than focused on one partner. Read full analysis →
Case 3: Rat + Horse (Score: 35 — Six Clash)
Step 1 — Branch relationship: Rat (子 Zi) and Horse (午 Wu) are a Six Clash (六冲) pair — they sit directly opposite each other on the zodiac wheel (positions 1 and 7). The classical texts describe this opposition as “Zi and Wu clash — water and fire battle” (子午冲). This is the most intense of the four friction frameworks.
Step 2 — Element interaction: Rat is Water; Horse is Fire. Water extinguishes Fire (水克火) — a destructive cycle in the Five Elements. This elemental opposition amplifies the branch clash, creating friction at both the animal and elemental levels simultaneously.
Step 3 — Personality dynamic: The Rat is strategic, cautious, and security-oriented. The Horse is impulsive, freedom-loving, and restless. The Rat wants to plan; the Horse wants to gallop. Without awareness, the Rat’s caution feels like control to the Horse, while the Horse’s spontaneity feels like chaos to the Rat.
Step 4 — Can this pair succeed? Yes — but it requires conscious effort. The classical texts do not say clashes are “impossible.” They say clashes require awareness. When both partners understand their natural friction points, they can:
• Channel the oppositional energy into complementary roles (the Rat handles planning; the Horse handles execution)
• Use their differences as a growth catalyst rather than a battleground
• Leverage a compatible Day Master to soften the animal-sign clash
Verdict: 35/100. The lowest scoring pair type, but not a verdict — a map of where the work is needed. Many successful Rat-Horse partnerships exist when both partners bring awareness. Read full analysis →
Understanding Compatibility Dimensions
Each compatibility pair page analyzes three dimensions of the relationship:
- Love & Romance — Emotional connection, intimacy potential, and long-term romantic prospects. High-scoring pairs tend to share complementary emotional rhythms, while lower-scoring pairs may need to consciously bridge different intimacy languages.
- Friendship — How naturally the two signs get along as friends, shared interests, and mutual support. Trine allies often form instant friendships; clash pairs may become close friends only after working through initial friction.
- Work & Business — Professional synergy, division of labor, and partnership potential. Some pairs that are moderate in romance excel in business (complementary skills), while others that sizzle romantically may struggle with shared finances.
The Four Relationship Frameworks
Chinese zodiac compatibility is determined by four interacting frameworks rooted in the Earthly Branches (地支). These frameworks are not modern inventions \u2014 they originate from the sexagenary cycle system formalized during the Han Dynasty (206 BCE \u2013 220 CE), which pairs each of the twelve branches with one of ten heavenly stems:
Six Harmonies (六合 Liu He) — Secret Friends
Six one-to-one pairings with exceptional natural chemistry. Each pair combines complementary energies that create balance. The concept of Six Harmonies is rooted in the Earthly Branches system, where each of the twelve branches forms exactly one celestial pairing:
“Zi and Chou combine into earth. Yin and Hai combine into wood. Mao and Xu combine into fire. Chen and You combine into metal. Si and Shen combine into water. Wu and Wei combine into the sun and moon.”
\u2014 Yuan Hai Zi Ping (\u6e0a\u6d77\u5b50\u5e73), by Xu Dashou, Song Dynasty. A foundational text of BaZi theory that first codified the transformation rules for Earthly Branch combinations. The Chinese zodiac assigns each branch an animal sign.
| 🐀 Rat + 🐂 Ox | 🐅 Tiger + 🐖 Pig |
| 🐇 Rabbit + 🐕 Dog | 🐉 Dragon + 🐓 Rooster |
| 🐍 Snake + 🐒 Monkey | 🐎 Horse + 🐐 Goat |
Learn more about Six Harmonies →
Three Harmonies (三合 San He) — Trine Allies
Four groups of three signs that form natural alliances. Members of the same trine tend to understand each other instinctively:
- Water Trine: Monkey, Rat, Dragon
- Metal Trine: Snake, Ox, Rooster
- Fire Trine: Tiger, Horse, Dog
- Wood Trine: Pig, Rabbit, Goat
Learn more about Three Harmonies →
Six Clashes (六冲 Liu Chong) — Direct Opposition
Six pairs that sit directly opposite each other on the zodiac wheel, creating dynamic tension:
| 🐀 Rat ↔ 🐎 Horse | 🐂 Ox ↔ 🐐 Goat |
| 🐅 Tiger ↔ 🐒 Monkey | 🐇 Rabbit ↔ 🐓 Rooster |
| 🐉 Dragon ↔ 🐕 Dog | 🐍 Snake ↔ 🐖 Pig |
Clashes create productive friction — not impossibility. Learn more about Six Clashes →
Six Harms (六害 Liu Hai) — Subtle Friction
Less visible than clashes but equally important. These pairs experience a quality of misunderstanding or misaligned effort — situations where both parties mean well but somehow work against each other:
| 🐀 Rat ↔ 🐐 Goat | 🐂 Ox ↔ 🐎 Horse |
| 🐅 Tiger ↔ 🐍 Snake | 🐇 Rabbit ↔ 🐉 Dragon |
| 🐒 Monkey ↔ 🐖 Pig | 🐓 Rooster ↔ 🐕 Dog |
Beyond the Animal Signs: Elements and BaZi
While the animal compatibility matrix is the most accessible layer, serious relationship analysis in Chinese astrology goes deeper. Each person’s Five Element profile (Wood, Fire, Earth, Metal, Water) adds crucial nuance \u2014 a Fire Horse and a Water Rat may clash more intensely than their animal signs alone suggest, because Fire and Water are elemental opposites.
“The Day Master is the root of the self. To judge marriage and partnership, one must examine not the year branch alone, but the Day Master’s relationship to the spouse palace. Two people whose Day Masters generate each other will find harmony even if their animal signs clash.”
\u2014 Di Tian Sui (\u6ef4\u5929\u968b), attributed to Liu Bo Wen, Ming Dynasty. A classical commentary on BaZi analysis that elevated Day Master theory. This principle explains why our animal-sign matrix is a starting point \u2014 for complete analysis, cast your full BaZi (Four Pillars) chart.
For the most accurate compatibility reading, both partners should cast their full BaZi charts. The Day Master (日主) — the stem of your birth day — reveals your core self and is far more precise for relationship analysis than the year sign alone.
The Five Elements Interaction Matrix
While the four branch relationship frameworks (Harmonies, Clashes, Harms) operate on the animal-sign level, the Five Elements (五行 — Wood, Fire, Earth, Metal, Water) provide a second, independent layer of analysis. Every zodiac sign carries a primary element, and every pair of elements interacts in one of four ways:
The Generating Cycle (相生 Sheng Sheng) — Nourishing
Each element generates (feeds) the next in a circular sequence. Generating pairs are naturally supportive:
| Wood generates Fire | Fuel feeds flame. Tiger/Horse, Rabbit/Snake |
| Fire generates Earth | Ash enriches soil. Horse/Dragon, Snake/Goat |
| Earth generates Metal | Mineral forms in rock. Dragon/Rooster, Ox/Rooster |
| Metal generates Water | Condensation on metal. Monkey/Rat, Rooster/Rat |
| Water generates Wood | Rain feeds growth. Rat/Rabbit, Pig/Rabbit |
The Controlling Cycle (相克 Ke Sheng) — Restraining
Each element controls (suppresses) another. Controlling pairs create tension that can be productive or destructive depending on balance:
| Wood controls Earth | Roots break rock. Tiger/Ox, Dragon/Rabbit |
| Earth controls Water | Dams contain floods. Dragon/Rat, Ox/Pig |
| Water controls Fire | Water extinguishes flame. Rat/Horse, Pig/Snake |
| Fire controls Metal | Heat melts metal. Horse/Monkey, Snake/Rooster |
| Metal controls Wood | Axe fells tree. Monkey/Tiger, Rooster/Rabbit |
“The five elements follow the pattern of generation and control. When generation and control are balanced, there is harmony; when one overwhelms the other, there is illness. The same principle applies to human relationships — the elements of two people must complement, not crush.”
— Di Tian Sui (滴天髓), attributed to Liu Bo Wen (刘伯温), Ming Dynasty. This text elevated Five Element balance theory to the center of BaZi compatibility analysis. See Wikipedia: Wuxing for the element cycle.
How to Read a Compatibility Report: A Step-by-Step Guide
You do not need to be a BaZi master to analyze a zodiac pair. Here is the same four-step framework used by practitioners, simplified for everyday use. Apply it to any pair — whether you are evaluating a romantic interest, a business partner, or a friendship.
Check the Branch Relationship
Are the two signs in the same Six Harmony pair? Same Three Harmony trine? Opposite each other on the wheel (Six Clash)? Or in a Six Harm relationship? This gives you the base score range (28–95).
Examine the Element Interaction
Look up each sign’s primary element (see the Five Elements Matrix above). Are they in a generating cycle (nourishing) or a controlling cycle (tension)? Adjust the base score: +3 to +5 for strong generating, −3 to −5 for strong controlling.
Consider the Personality Dynamic
Each animal has core personality traits. Do they complement (e.g., strategic Rat + steady Ox) or conflict (e.g., cautious Rat + impulsive Horse)? This step is qualitative — it tells you where the friction or harmony will manifest.
Refine with the Day Master (Advanced)
If you know both partners’ full BaZi charts, examine the Day Master (日主) — the heavenly stem of the birth day. Day Master compatibility can override or reinforce the animal-sign score. Cast your BaZi chart →
✓ Pro tip: For most everyday situations, Steps 1–3 are sufficient. Step 4 (Day Master) matters most for marriage decisions and long-term business partnerships, where the precision of a full BaZi chart justifies the effort.
Apply This Framework: Try the Calculator →
About This Methodology Guide
This page is the methodology companion to our Compatibility Calculator. While the calculator gives you instant scores for any of the 78 pairs, this guide explains how those scores are derived and what they mean in practice.
What this guide covers: The four classical branch relationship frameworks (Six Harmonies, Three Harmonies, Six Clashes, Six Harms), the Five Elements interaction layer, BaZi Day Master refinement, score distribution analysis, worked case studies, and a step-by-step guide for analyzing any pair.
What this guide does NOT cover: Detailed analysis of individual pairs (each pair has its own dedicated page — see our calculator for links), full BaZi chart casting, or non-animal-based compatibility systems (Western astrology, numerology). For those, see our BaZi calculator.
How does Chinese zodiac compatibility actually work?
Chinese zodiac compatibility is determined by the interaction patterns of the twelve Earthly Branches (地支). Four classical frameworks govern all 78 unique pairs: Six Harmonies (六合) for the 6 best matches, Three Harmonies (三合) for trine allies, Six Clashes (六冲) for the 6 most challenging pairs, and Six Harms (六害) for subtly antagonistic pairs. The Five Elements (五行) add a second layer of analysis. This has been the theoretical foundation since the Han Dynasty (206 BCE).
What is the difference between Six Harmonies and Three Harmonies?
Six Harmonies (六合) are one-to-one 'secret friend' pairings — each of the 12 branches has exactly one celestial partner, producing 6 unique pairs that score 90+. Three Harmonies (三合) are group alliances of three signs each (4 groups total), where any two members of the same trine share natural chemistry scoring 82+. Six Harmony is more focused and intense; Three Harmony is more broad-based and stable.
Why do some animal pairs clash in Chinese astrology?
Six Clashes (六冲) occur when two branches sit directly opposite each other on the zodiac wheel (positions 1 vs 7, 2 vs 8, etc.). This 180-degree opposition creates a natural energy tension. For example, Rat (Water) clashes with Horse (Fire) because Water extinguishes Fire. The clash is not a curse — it is a map of where conscious effort is needed. Many successful relationships exist between clashing signs.
How accurate is zodiac compatibility without a full BaZi chart?
Animal-sign compatibility provides the foundational layer — roughly 60-70% of the total picture. The remaining 30-40% comes from the Five Elements interaction and the BaZi Day Master (日主), which requires both partners' full birth data (year, month, day, hour). For casual curiosity, animal signs are sufficient. For marriage or major partnership decisions, a full BaZi reading is recommended.
What are the Six Harms (六害) in Chinese zodiac?
Six Harms (六害 Liu Hai) are a secondary friction framework — six pairs that experience subtle, persistent misunderstanding rather than overt conflict. Unlike Six Clashes (which are direct oppositions), Six Harm pairs don't sit across from each other, but their branch interaction produces a quality of misaligned effort. Examples include Rat-Goat, Ox-Horse, and Tiger-Snake. They typically score 38-45.
Can Five Elements change my zodiac compatibility score?
Yes. The Five Elements (五行) add a modifying layer. If two signs have a generating element relationship (e.g., Wood generates Fire), the base compatibility score may increase by 3-5 points. If they have a controlling relationship (e.g., Water controls Fire), the score may decrease by 3-5 points. This is why some moderate pairs feel surprisingly good (or bad) in practice — the elements are amplifying or dampening the base branch relationship.