Couple compatibility: marriage & partnership

Check whether two birth years match or clash, for marriage or for going into business together. Enter both birth years (add day and month so the lunar year comes out right) to see four things: zodiac animal, heavenly stem, birth-year element and Eight Mansions group, each judged on its own, with no overall percentage.

Traditional systemsOne school's rules, not empirically tested.

Where this comes from

A folk lookup on four aspects, each stated separately: the zodiac animal (Three Harmonies, Six Combinations, Four Clashes, Six Harms), the heavenly stem (five combining pairs, four clashing pairs), the Nạp Âm element of the birth year, and the Kua number of the Bát Trạch school. The lunar birth year is computed; the four tables are conventions, and schools do not agree on which aspect weighs more.

Birth date, person 1

Birth date, person 2

Enter the solar birth year. Day and month are optional, used only to convert to the lunar year: anyone born between early January and roughly 20 February usually still carries the previous year's animal sign.

Gender, person 1

Gender, person 2

Set gender to unlock the Eight Mansions axis, most useful when the two will share a home.

What is this for?

Three Harmony / Six Combination / Four Clash / Six Harm table by zodiac animal

Animal	Three Harmony	Six Combination	Four Clash	Six Harm

Classical allusion

“Dẫu có bạc vàng trăm vạn lạng, chẳng bằng kinh sử một vài pho.”

Translation: A million taels of silver and gold are worth less than a few volumes of the classics and histories.

Lê Quý Đôn · A couplet hung in his study

Wedding date picker

You've checked the two ages. Wedding dates ranks the days in your chosen range by the bride's and groom's ages.

Open Wedding date picker

Where the schools differ

The Four Clashes and the six opposite clashes

Nhật Nguyệt usesThe page treats the Four Clashes in groups of four (Dần Thân Tỵ Hợi; Tý Ngọ Mão Dậu; Thìn Tuất Sửu Mùi), as Vietnamese folk age matching does, after the Three Harmonies and Six Combinations; the comment names only the opposite pairs a clash.

The other wayThe books (Wuxing Dayi, the Ziping texts) call only the six opposite pairs such as Tý Ngọ a clash; the other pairs in a group of four are punishment, break or harm, as Tý and Mão punish each other.

What no one has shown

No study has shown that two people's birth years decide whether they suit each other. That is why the page does not merge the four aspects into a percentage.

Read on

What research saysDoes the Barnum Effect Work on Eastern Horoscopes? A Comparative Experiment with Westerners and Chinese Participants What research saysDo Two People Born at the Same Time Share the Same Fate? What the London 'Time Twins' Study Says GlossaryWhat is Tam Hợp?GlossaryWhat is Tứ Hành Xung?

Ask Nhật Nguyệt AI

Which ages form the Three Harmonies and the Four Clashes?How is the Nạp Âm element of a birth year looked up?

Learn more

What does a couple compatibility check look at?

The page compares two birth years on four counts, each read separately: zodiac animal, heavenly stem, birth-year element (Na Yin) and Kua group. The four often point different ways. The animals may be neither matching nor clashing while the elements feed each other.

Animals: the Three Harmony groups are three animals four years apart, such as Monkey, Rat and Dragon, counted as the best match. The Six Combinations are six matched pairs, such as Rat and Ox, Tiger and Pig. The Four Clash groups are a Vietnamese folk grouping of four animals, such as Rat, Horse, Cat and Rooster; within a group, only the opposite pair such as Rat and Horse is a clash in the books. The Six Harm pairs are said to get in each other's way. Most couples fall into none of these.

The heavenly stem is the word before the animal in a year's name, such as Canh in Canh Ngọ. The ten stems form five matching pairs (Giáp Kỷ, Ất Canh, Bính Tân, Đinh Nhâm, Mậu Quý) and four clashing pairs (Giáp Canh, Ất Tân, Bính Nhâm, Đinh Quý).

The birth-year element is what Vietnamese people mean when they ask each other's 'mệnh', such as Lộ Bàng Thổ (roadside earth) or Kiếm Phong Kim (sword-edge metal). Elements that feed each other count as a match, elements that check each other as a clash. When weighing a marriage, many families look at this before the animal.

The Kua group needs both people's sex. It divides everyone into an East and a West group, and only tells you whether two people suit the same set of house directions.

Everything is looked up by lunar year. If you were born between early January and Tết, you belong to the previous lunar year, so enter the birth day and month for a correct conversion. Schools disagree on which part weighs more, which is why the four are never merged into one percentage.

The 12 animals: Three Harmony, Six Combination, opposite clash (Six Clash) and Six Harm
Animal (branch)	Three Harmony (best match)	Six Combination (pair)	Opposite clash (Six Clash)	Six Harm
Tý (Rat)	Thân, Thìn	Sửu	Ngọ	Mùi
Sửu (Ox)	Tỵ, Dậu	Tý	Mùi	Ngọ
Dần (Tiger)	Ngọ, Tuất	Hợi	Thân	Tỵ
Mão (Cat)	Hợi, Mùi	Tuất	Dậu	Thìn
Thìn (Dragon)	Thân, Tý	Dậu	Tuất	Mão
Tỵ (Snake)	Dậu, Sửu	Thân	Hợi	Dần
Ngọ (Horse)	Dần, Tuất	Mùi	Tý	Sửu
Mùi (Goat)	Mão, Hợi	Ngọ	Sửu	Tý
Thân (Monkey)	Tý, Thìn	Tỵ	Dần	Hợi
Dậu (Rooster)	Tỵ, Sửu	Thìn	Mão	Tuất
Tuất (Dog)	Dần, Ngọ	Mão	Thìn	Dậu
Hợi (Pig)	Mão, Mùi	Dần	Tỵ	Thân

Frequently asked questions

What do I need to enter?

Both birth years are enough for three of the four parts. Add day and month to get the lunar year right, and sex to see the Kua part as well.

Can two people whose animals clash marry?

The table only says the two may clash over how things are done. It cannot say whether two people suit each other, and the other three parts may point the other way.

Which part matters most?

Schools disagree. When weighing a marriage, many families look at the birth-year element first, then the stem and the animal. The Kua group is about choosing house directions, not about feelings.

Is a business match read differently from a marriage match?

The lookup is the same. Only the overall remark changes with the purpose you pick, love or business.

If I was born in January, which year counts?

The lunar year. If you were born before Tết you belong to the previous lunar year, and one year off changes the animal, stem, element and Kua group. Enter your birth day and month and the page converts it.

Why is there no compatibility percentage?

Because no school has a shared scale for the four parts. A figure like 72% looks precise but is only an arbitrary sum, so the page reports each part on its own.

Public API, returns JSON, no sign-in: GET https://api.nhatnguyet.org/api/v1/calc/xem-tuoi-hop?nam1=1990&nam2=1992