What Marital Compatibility Really Checks: No 'Compatible or Not' in BaZi
A friend got engaged last month. The first time the two families met, her mother pulled out a red envelope with two red slips of paper inside, each bearing a birth date and time.
"I don't believe in this," she told me, "but my mom does. If it puts her at ease, fine — let it be checked."
I asked her: do you actually know what marital compatibility checking checks?
She paused for two seconds and said, "Just... whether our zodiac signs are compatible?"
That is exactly what most people assume the answer is — and it is the crudest layer of marital compatibility (hehun).
First, a look at the reality
On South Korea's recent trending searches, the terms 국제결혼 (international marriage), 이혼 (divorce), 결혼식 (wedding) and 시어머니 (mother-in-law) have all appeared. Showing up on the same list on the same day does not mean they are related, but it does show at least one thing — in East Asia, marriage has never been only about two people.
According to the 2025 marriage and divorce statistics released by Statistics Korea (formerly the National Statistical Office; published March 2026), there were about 240,000 marriages over the year, of which about 21,000 were marriages to a foreign spouse. That works out to roughly one in every eleven or twelve couples being a cross-border marriage. This is probably the soil in which the habit of "checking the BaZi" has survived for centuries — which is, in fact, not so surprising.
The three layers of marital compatibility, from coarse to fine
Layer one: the Chinese zodiac. The best-known relationships of the six harmonies, three harmonies and clashes — for example, someone born in a Tiger year clashes with someone born in a Monkey year.
Layer two: the day pillar. In BaZi (Four Pillars), the earthly branch of the day pillar is called the "spouse palace"; what it looks at is how two people interact within a relationship, not whether they are "compatible."
Layer three: complementary useful gods (yongshen). This is the more refined layer — it does not ask whether two people are alike, but whether their charts can benefit each other.
| Layer | What it looks at | Limitation |
|---|---|---|
| Chinese zodiac | Earthly branch relationships (six harmonies / three harmonies / clashes) | Sees only the birth year — far too crude |
| Day pillar | The spouse palace, and the relationship between the day stem and day branch | Needs the full birth date and time; the year alone will not do |
| Useful gods | Whether the two natal charts can benefit each other | The conclusion depends heavily on the interpreter's skill |
One saying comes up often in the divination tradition: of all the methods of marital compatibility, the worst is to stay at the surface. A zodiac clash does not mean a couple cannot work out, and a zodiac six-harmony does not mean everything will go smoothly.
Where marital compatibility is genuinely useful
I later told my friend: don't treat it as a score — treat it as a relationship manual.
It does not tell you whether you "can get married." What it may point out is where the two of you tend to grind against each other, whose temper needs more forbearance, and what to watch out for in certain years. How you use that is your choice.
The ancient procedure was in fact very practical: the two sides exchanged gengtie (betrothal cards), writing the birth data on red paper and sending it to the other household. What was being checked was "whether the two families can move this matter forward with peace of mind." It was a procedure, not a verdict.
If you are standing in this kind of year right now
Marital compatibility cannot produce your answer. If you want to see a relationship a little more clearly, you can describe your actual situation clearly, let 占卜迷指 recommend a suitable method, and produce a reading for you to judge for yourself — it does not decide for you, and it does not predict outcomes.
What truly shapes a marriage is whether two people are willing to keep communicating over the same small thing, again and again. No red slip of paper can calculate that.
Sources
- Statistics Korea (formerly the National Statistical Office), 2025 Marriage and Divorce Statistics, official release (2026-03-19)
- Korea Times: Korea's number of marriages rises to a 7-year high in 2025 (including 21,000 marriages to foreign spouses)
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