The relationships behind compatibility
Every animal is an earthly branch, and the branches interact in a small number of fixed ways. These are the same relationships used in BaZi and date selection, which is why zodiac compatibility is more than folklore about personalities.
Six Harmonies (六合)
Six pairs that combine: Rat–Ox, Tiger–Pig, Rabbit–Dog, Dragon–Rooster, Snake–Monkey, Horse–Goat. Traditionally the closest one-to-one match.
Three Harmonies (三合)
Four groups of three animals, four years apart, that share an element: Monkey–Rat–Dragon (Water), Snake–Rooster–Ox (Metal), Tiger–Horse–Dog (Fire), Pig–Rabbit–Goat (Wood). Any two from the same group are considered a natural team.
Six Clashes (六冲)
Animals six years apart sit directly opposite each other on the zodiac wheel: Rat–Horse, Ox–Goat, Tiger–Monkey, Rabbit–Rooster, Dragon–Dog, Snake–Pig. This is the most important warning sign in traditional matching.
Harms, punishments and breaks
Weaker negative relationships. The six harms (六害) are Rat–Goat, Ox–Horse, Tiger–Snake, Rabbit–Dragon, Monkey–Pig and Rooster–Dog. The punishments (刑) include the Tiger–Snake–Monkey and Ox–Goat–Dog groups, Rat–Rabbit, and the "self-punishment" of the Dragon, Horse, Rooster and Pig with their own sign. Breaks (破) are the mildest.
A pair can carry more than one relationship — Snake and Monkey, for example, are a Six Harmony and also a punishment and a break — so readers usually look at which one is strongest. The ranking here puts clashes first, then harmonies, then the weaker negatives.
Compatibility chart
| Rat | Ox | Tig | Rab | Dra | Sna | Hor | Goa | Mon | Roo | Dog | Pig | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rat | · | ♥ | · | ~ | ♥ | · | ✕ | ~ | ♥ | ~ | · | · |
| Ox | ♥ | · | · | · | ~ | ♥ | ~ | ✕ | · | ♥ | ~ | · |
| Tiger | · | · | · | · | · | ~ | ♥ | · | ✕ | · | ♥ | ♥ |
| Rabbit | ~ | · | · | · | ~ | · | ~ | ♥ | · | ✕ | ♥ | ♥ |
| Dragon | ♥ | ~ | · | ~ | ~ | · | · | · | ♥ | ♥ | ✕ | · |
| Snake | · | ♥ | ~ | · | · | · | · | · | ♥ | ♥ | · | ✕ |
| Horse | ✕ | ~ | ♥ | ~ | · | · | ~ | ♥ | · | · | ♥ | · |
| Goat | ~ | ✕ | · | ♥ | · | · | ♥ | · | · | · | ~ | ♥ |
| Monkey | ♥ | · | ✕ | · | ♥ | ♥ | · | · | · | · | · | ~ |
| Rooster | ~ | ♥ | · | ✕ | ♥ | ♥ | · | · | · | ~ | ~ | · |
| Dog | · | ~ | ♥ | ♥ | ✕ | · | ♥ | ~ | · | ~ | · | · |
| Pig | · | · | ♥ | ♥ | · | ✕ | · | ♥ | ~ | · | · | ~ |
♥ harmony · ✕ clash · ~ harm, punishment or break · · no special relationship
Questions
Does a clash mean a relationship won't work?
No. In traditional practice it's one factor among many; a full comparison looks at both people's BaZi charts, not just the year animals.
What about the same sign?
Two people of the same sign are usually considered compatible, except for the Dragon, Horse, Rooster and Pig, which carry a "self-punishment".