Free tool
Compatibility: love & partnership
Compatibility is not one number but four axes read separately: earthly branch, heavenly stem, Na Yin element and Kua number. The familiar zodiac table is only one of the four, and schools do not agree on how to weight them. The axes usually disagree, so collapsing them into a single percentage hides the very part worth knowing.
Four axes, not just the zodiac animal: earthly branch, heavenly stem, sound element and Eight Mansions group. Each is read separately because they often disagree, and none of it is averaged into a percentage. Add a day and month and the page converts to the lunar year for you.
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What are Three Harmony, Four Clash, and Six Harm?
Checking compatibility between two people (for romance, marriage, or business partnership) in East Asian culture usually relies on the relationship between the Earthly Branches (tied to the 12 zodiac animals) of their birth years, grouped into 3 fixed relationship sets long recorded in classical Tử Bình/Tử Vi texts: Three Harmony (3 Branches spaced 4 positions apart on the 12-Branch circle, considered the most compatible, e.g. Thân-Tý-Thìn), Four Clash (Branches directly opposite each other across the circle, such as Tý clashing with Ngọ, Sửu with Mùi... considered conflicting), and Six Harm (specific Branch pairs believed to cause friction or loss for each other).
These relationship groups derive from Five Elements theory and the 12-Branch cycle in the I Ching/Tử Bình system. Geometrically, they're just positional relationships among 12 points on a circle (30 degrees apart), assigned generative/conflicting meaning by traditional Elemental theory, not empirical observation of personality compatibility.
This tool only cross-references two birth years against those 3 relationship groups for a reference-level conclusion (harmonious / needs attention), a narrow slice of the fuller traditional compatibility system (which also weighs detailed elemental destiny and can even compare both people's full Tử Vi charts), so it's a fun, quick reference rather than the sole basis for a major decision like marriage: real-life compatibility depends on far more than birth year alone.
There is also a less commonly cited fourth grouping, Lục Hợp (Six Combinations), pairing adjacent-ish Branches (like Tý with Sửu, Dần with Hợi) into harmonious pairs distinct from the 3-member Three Harmony groups. This tool focuses on the 3 relationships most consistently referenced across compatibility guides (Three Harmony, Four Clash, Six Harm) rather than every minor grouping found across different regional traditions, to keep the result easy to interpret.
Three Harmony groups are also each tied to one of the 4 Elements, forming an "elemental bureau" (cục): Thân-Tý-Thìn forms a Water bureau, Dần-Ngọ-Tuất a Fire bureau, Tỵ-Dậu-Sửu a Metal bureau, and Hợi-Mão-Mùi a Wood bureau. Two people within the same Three Harmony group are considered doubly compatible, sharing both the positional harmony and the same elemental bureau, which is why this grouping is traditionally regarded as the strongest of the three relationships.
Four Clash pairs sit exactly opposite each other on the 12-Branch circle (180 degrees apart) and are traditionally considered the most direct form of conflict, stronger in effect than Six Harm, though folk interpretation varies on exactly how much weight to give it versus the elemental (Nạp Âm) compatibility between two people, which some traditions treat as more decisive for romantic relationships specifically.
| Zodiac animal (Branch) | Three Harmony (most compatible) | Four Clash (conflicting) | Six Harm (friction) |
|---|---|---|---|
| Tý (Rat) | Thân, Thìn | Ngọ | Mùi |
| Sửu (Ox) | Tỵ, Dậu | Mùi | Ngọ |
| Dần (Tiger) | Ngọ, Tuất | Thân | Tỵ |
| Mão (Cat/Rabbit) | Hợi, Mùi | Dậu | Thìn |
| Thìn (Dragon) | Thân, Tý | Tuất | Mão |
| Tỵ (Snake) | Dậu, Sửu | Hợi | Dần |
| Ngọ (Horse) | Dần, Tuất | Tý | Sửu |
| Mùi (Goat) | Mão, Hợi | Sửu | Tý |
| Thân (Monkey) | Tý, Thìn | Dần | Hợi |
| Dậu (Rooster) | Tỵ, Sửu | Mão | Tuất |
| Tuất (Dog) | Dần, Ngọ | Thìn | Dậu |
| Hợi (Pig) | Mão, Mùi | Tỵ | Thân |
Frequently asked questions
Do I need an exact birth date to check compatibility?
Just the (lunar) birth year of both people, since Three Harmony/Four Clash/Six Harm are all based on the birth-year Branch, no detailed day/hour needed.
Which is stronger, Three Harmony or Four Clash?
By traditional belief, Three Harmony is considered the most compatible relationship (sometimes sharing the same elemental bureau too), while Four Clash (directly opposite on the circle) is usually seen as a more direct and stronger form of conflict than Six Harm.
Does a Four Clash pairing mean two people definitely aren't compatible?
It shouldn't be taken as an absolute verdict. This is one cultural-reference slice based on birth year alone, not accounting for detailed elemental destiny or the many real-life factors that actually determine compatibility.
Can this tool be used for both romantic and business compatibility?
Yes, Three Harmony/Four Clash/Six Harm relationships are traditionally referenced for romance, marriage, and business partnerships alike, not limited to one relationship type.
What does Six Harm mean?
6 specific Branch pairs believed to cause friction or loss for each other, considered milder than Four Clash but still worth noting per folk tradition.
Are there other relationship groupings besides these 3?
Yes, such as Lục Hợp (Six Combinations, 6 harmonious pairs), but it's referenced less consistently across sources than the 3 groups covered here, so this tool focuses on the 3 most commonly cited relationships.
Is zodiac compatibility scientifically grounded?
No, this is a folk divination system based on the geometric positions of the 12 Branches on a circle, not empirical observation of personality compatibility.