Compatibility · 宿曜经

The 9 Types of Connection: A 1,200-Year-Old Map for Why Some People Click and Others Crack

Western astrology says we're “compatible” or “incompatible.” A 759 CE Buddhist text says it's more specific than that — and names every relationship from a set of nine.

January 2026 · ~8 min read

There's a friendship I've had since I was 19. We don't talk for six months. Then she sends me a voice note about a kitchen renovation and we're back inside the same conversation we left. Nothing repaired. Nothing reset. Just — picked up.

I have another friend I've known for the same number of years. He's careful with me, I'm careful with him, we share three group chats, our birthdays are within a week of each other. He is a good person. The relationship has never not felt like work.

For years I assumed this was about effort, or chemistry, or being an introvert, or “energy” — that placeholder word we use when we mean I don't know what this is but I can feel it.

Then someone showed me a system that put a name on it. The first relationship has a name. The second has a different name. They aren't on a “good vs. bad” axis. They are different categories of thing, the way an apple and a hammer are different categories of thing.

The system is called 宿曜经 (Sukuyō Kyō). It was translated from Sanskrit into Chinese in 759 CE by a Buddhist monk named Amoghavajra (不空), who lived in Chang'an under the Tang court. It is one of the few astrology texts that survived both the suppression of Buddhism in China and the gradual loss of Indian astronomical sources. It traveled to Japan with Kūkai in the 9th century. It has been used continuously, in fragmentary form, ever since.

It says there are nine kinds of relationships between two people. Not nine outcomes — nine qualities. Once you have the language, every relationship in your life snaps to one.

This is not the Western “compatibility” question. The Western question asks will this work. The 宿曜经 question asks what is this. That turns out to be the more useful question.

The nine categories

I'll describe each one the way I'd describe a kind of weather: not as a verdict, but as a thing that has a shape. Some are easier than others. None of them are bad. (You'll see why.)

命

Fate — the mirror person

Sometimes a sibling, a partner, or a stranger you meet once and never forget. They show you yourself — your tics, your defaults, your unexamined moves — at a resolution you can't get from a real mirror. The relationship feels uncanny in both directions.

業

Karma — unfinished business

Not a curse — an invoice. There's a thing the two of you have to work through, and the relationship keeps producing chances to do it until you do. Often a parent. Often that one ex.

胎

Origin — the womb relationship

Foundational. The person without whom the rest of your life wouldn't have been possible. Mothers often land here; sometimes a teacher, sometimes a city. You can't really see it while you're inside it — it's the water, not the fish.

榮

Glory — the elevator

They make you better — not by demanding it, just by being themselves. You stand a little straighter near them. The risk: you can mistake Glory for romance because the feeling is so good. (It usually isn't romance. It's altitude.)

衰

Decline — the drainer

The relationship pulls you slightly downward — your standards, your energy, your sense of self — in ways small enough to deny for years. Decline doesn't mean you should leave; it means you should know.

危

Danger — magnetic chaos

The person you cannot look away from and cannot trust. It has weather, not a climate. People mistake Danger for love because it activates every nerve at once. Name it so you stop confusing it with other things.

安

Peace — the easy one

Being together costs nothing. No performance, no recovery time, no last-message anxiety. Peace looks low-stakes from outside but is statistically the rarest — most people have one or two in a lifetime.

成

Success — the builder

Two of you in this configuration make things — companies, families, projects, art. Forward motion is built into the connection. The relationship is the boat, not the destination.

壞

Destruction — the unmaker

Sounds bad. Sometimes is. Often it's the relationship that ends a version of you that needed to end. Western culture calls it “toxic” or “growth” depending on the outcome; 宿曜经 calls it Destruction either way, because the function is the same.

“Isn't this just confirmation bias?”

The honest answer: yes, partly. Any framework with nine boxes will catch any relationship.

The less-honest-and-more-interesting answer: the boxes were not chosen at random. The 宿曜经 categories are derived from the pattern of two birth dates against a 27-station lunar map (it predates the more familiar 28-mansion system). The system was tested for a thousand years before it reached you. People used it to choose marriages, schedule diplomacy, decide who to study with. That doesn't make it true. It makes it thick — refined by a lot of pressure over a long time.

What I can tell you from running it against my own life: about 70% of my relationships snapped to a category immediately. The remaining 30% snapped only after I stopped lying to myself about what the relationship actually was. That's a useful tool even if you think the cosmology is metaphorical.

The risk of the system isn't that it's wrong. The risk is using it as a verdict — we're an Origin pair, so I have to stay / we're a Decline, so I have to leave. The categories don't tell you what to do. They tell you what you're working with.

A small historical aside

If you're curious why a Buddhist monk in Tang-dynasty China was translating a Sanskrit text on stars: the Tang court wanted better calendars, the Buddhist clergy were the people who knew Sanskrit, and Indian astronomy was 400 years ahead of Chinese astronomy at the time. Amoghavajra was one of the most prolific translators in the history of any language — he rendered something like 110 sutras into Chinese — and 宿曜经 was, in his words, the practical one. The court used it. So did the merchants. So did the matchmakers.

Most of what we now call “Chinese astrology” in the West (zodiac animals, simple year-based readings) postdates 宿曜经 by centuries and is much coarser. The 9-category system is not common knowledge even inside China today. It survived in fragments — a chapter here, a transmission lineage there, a Japanese reprint in the Meiji era. We're rebuilding it.

How to find yours

Working out your own 9-category map is mechanical: you need both birth dates (a birth time and place refine the result), the system computes the 27-station offset between the two, and the offset deterministically maps to one of the nine categories. There's no interpretation step at the calculation level. The interpretation is what you do with the name afterward.

I built Qiglow so I could run this for myself without learning a 1,200-year-old computational scheme by hand. It does the math. It also does a daily Five Elements reading and a 30-second ritual, but for the compatibility piece specifically: you put in two birth dates, you get the category, you get a description in modern English, you decide what to do with it.

You don't need an app to use this framework — you can do the math yourself with a 宿曜经 reference table and a pen. I'm putting the link here because if you got this far, I assume you'd rather have the tool than the lookup chart.

Find your nine

Enter two birth dates. Get the category, and a description in plain modern language.

Try Qiglow →

One last thing

The reason I'm writing this is not because I think astrology is true. I think astrology is a vocabulary, and the vocabulary you have shapes what you can see. English has one word for “love.” Greek had four. People who learn Greek don't suddenly love more — they just notice distinctions they were already living through.

宿曜经 is a vocabulary for the specific quality of a connection between two people. Once you have it, you can't unsee the categories in your own life. The friendship from the start of this essay is Peace. The one that always feels like work is Glory pretending to be Peace, which is why it never quite resolves. My mother is Origin. The relationship I almost married is Danger. The job I quit is Destruction, and I'm grateful for it.

You probably have a Peace person you under-appreciate. You probably have a Decline relationship you've been minimizing. You probably have a Glory friend you keep mistaking for someone you should be dating.

Names help.