how it's matched today — palm leaf to app

Strip the ceremony away and the old job was arithmetic plus lookup.

Find where the moon was at each birth. That needed an almanac — a panchang — and in South India these were kept for centuries on palm-leaf manuscripts, recopied as the leaves decayed. Then convert each moon position into a birth star and a moon sign. Then run eight table lookups and add up the result.

The hard part was never the judgement. It was the ephemeris — knowing where the moon actually was on a given day, in a given place, decades ago. That knowledge was scarce, and scarcity is what made it a profession.

Once the moon's position became something anyone could compute to the arcsecond on a phone, the scarce part evaporated. What was left was eight lookup tables. Tables are the easiest thing in the world to put in software.

Here we have to be careful, because a lot of confident percentages float around and most of them have no source underneath.

What nobody has measured: the proportion of Indian families who match kundalis before a marriage. Pew didn't ask it. The national health and household surveys don't ask it. Every "X% of Indians match horoscopes" figure we chased traced back to an astrology site with no methodology. So we won't give you one.

What has been measured — and it's still striking:

Put those together and you can see the shape without inventing a statistic. A large majority of marriages involve the family in the choosing, and a large majority of households already run their calendar on auspicious timing. Chart matching sits precisely at that intersection. It doesn't need a survey to explain why it's everywhere.

The matrimonial platforms didn't invent the practice. They industrialised the distribution.

Look at what the free calculator is doing commercially. It is a lead magnet. It costs nothing to run — it's two moon longitudes and eight lookups — and it produces a number people feel compelled to act on. That's about as efficient as marketing gets.

We'd rather say that out loud than pretend otherwise, since we also give a first compatibility read for free. The difference we'd argue for isn't whether a tool is free. It's whether it tells you what it doesn't know.

Under any of these calculators, the whole thing is four steps:

Two honest consequences of that.

It is genuinely deterministic. Two correct implementations must agree. When two sites give you different scores, one of them has a bug, a different ayanamsa setting, or a different assumption about your birth time — not a different opinion.

And the resolution is coarser than it looks. The moon crosses a birth star in about a day. So everyone born within roughly the same 24-hour window shares a birth star — and therefore scores identically on the 21 points that come from it. The other 15 can still differ, because a birth star sometimes straddles two moon signs. Even so: a 32-out-of-36 is mostly a statement about two days on a calendar, not about you two specifically.

Which brings us back to the thing we keep hammering: step one is where the accuracy lives. Get the birth time wrong and everything downstream is precise arithmetic on the wrong input. the measured version of that is here.

Alongside guna milan sits mangal dosha — also called kuja dosha or manglik — an affliction said to arise when Mars falls in certain houses. The house lists vary between traditions, which is itself telling.

Here is the structural point. The 36-point score uses only the moon. Mars is not in it. So mangal dosha is mathematically invisible to guna milan — which is exactly why every platform runs the two checks side by side, and why a full 36 out of 36 doesn't end the conversation.

The traditional remedies are the part that reached the news. A manglik may be symbolically married first to a tree, an animal or an object — marrying a clay pot is called kumbh vivah — so the affliction lands on the stand-in. Two mangliks marrying each other is also held to cancel it.

The remedies surface in the press every few years around a high-profile Indian wedding, usually as rumour and usually denied by the families involved. The more interesting part is that the practice has drawn legal objection inside India — the argument being that a ritual treating a person as carrying an affliction to be transferred is demeaning, and lands hardest on women. We're not going to attach anyone's name to an unconfirmed ceremony; the criticism stands on its own.

Worth noting for balance: a 2019 paper in the Journal of Beliefs & Values building a measure of Indian superstitions used the manglik belief as one of its validated scale items. That's how the academic literature currently classifies it.

Here is the finding we found most surprising, and we went looking hard.

The ashtakoot system has been in continuous use for centuries. It produces a tidy integer from 0 to 36 for what must be hundreds of millions of marriages. It is the ideal shape for a study — a clean score in, an outcome out.

As far as we can find, nobody has ever run it properly. The nearest thing we located is a 2020 survey of nineteen couples in a minor jyotisha journal — far too small to conclude anything in either direction. No adequately powered study appears to exist: not one showing the score predicts marital outcomes, not one showing it doesn't.

The nearest large test is from a different tradition entirely. In 2008 the demographer David Voas used 2001 census data for England and Wales — over 10 million married couples, the largest test of astrology ever attempted — to check whether sun-sign combinations affected who married whom and who stayed married. An apparent signal turned out to be a recording artefact: people filling in their own birthday for their spouse. His conclusion: astrological sign has no impact on the probability of marrying, and staying married to, someone of any other sign.

We're also not going to run the comparison you might expect. India's measured divorce figure is very low — the 2011 census puts divorce at about 0.24% of the married population, with separation nearly three times that. It is tempting to hang that on chart matching. Don't. It's a different kind of measurement from the divorce rates quoted for other countries, so the numbers aren't comparable — and the same research found dissolution is highest in the regions where women have the most autonomy, which points at how hard it is to leave rather than at how well matches were made.

Roughly where we started this series.

It's an old, carefully built, internally consistent way of putting two temperaments side by side. It asks eight questions that are, honestly, better questions than "what's your sign." It's fast, it's reproducible, and it doesn't flatter you.

It is also derived from two numbers, has a pass mark nobody can source, can waive nearly any bad result through cancellation rules, and has never been seriously tested against an outcome.

Both of those are true at once. The way we try to hold it: a score is a good place to start a conversation and a poor place to end one. Which is why we show you the eight lines rather than one number, and why we'll tell you plainly when a missing birth time means some of those lines aren't settled yet.