You check Tamil Porutham for a match. Rajju passes. Score is 6 out of 10.
You check Kerala Porutham for the same couple. Rajju fails. Score drops to 5 out of 10.
Same two people. Same birth details. Same nakshatras. Different results.
If this has confused you — or if you have seen two websites give different Porutham scores for the same match — this article explains exactly why it happens.
Tamil Porutham and Kerala Porutham Are Not the Same System
Most people assume Tamil Porutham and Kerala Porutham are the same thing with a different name. They are not.
Both systems evaluate 10 compatibility factors based on the Moon nakshatra of the bride and groom. Both are called Dashakoot or 10-factor matching. Both are used across South India.
But the rules for calculating several of those 10 factors are completely different between the two traditions.
Tamil Porutham follows the classical Tamil Jyotish tradition. Kerala Porutham follows the Prashna Marga — a foundational Kerala Jyotisha text — which defines its own nakshatra groupings and calculation rules.
These are two distinct traditions that evolved separately. The fact that they share the same 10 factor names does not mean they use the same rules to calculate them.
A Real Example — Same Couple, Two Different Results
To make this concrete I will use a real report generated from my app Kundali Milan Pro — with placeholder names, no real client data.
Boy: Mumbai, Maharashtra | Moon nakshatra — Bharani Pada 3 (Aries) Girl: Chengam, Tamil Nadu | Moon nakshatra — Chitra Pada 3 (Libra)
Here are the results side by side:
| Factor | Tamil Porutham | Kerala Porutham |
|---|---|---|
| Dina | ✗ Madhyamam | ✗ Madhyamam |
| Gana | ✗ Athamam | ✗ Athamam |
| Mahendra | ✓ Uthamam | ✓ Uthamam |
| Sthree Deergha | ✓ Uthamam | ✗ Madhyamam |
| Yoni | ✗ Madhyamam | ✗ Athamam |
| Rasi | ✗ Madhyamam | ✓ Uthamam |
| Rasi Athipathi | ✗ Madhyamam | ✓ Uthamam |
| Vasya | ✗ Athamam | ✗ Athamam |
| Rajju | ✓ Uthamam | ✗ Athamam |
| Vedha | ✓ Uthamam | ✓ Uthamam |
| Total | 6/10 — Madhyamam | 5/10 — Athamam |
Five factors give different results for the exact same couple. Not one or two — five.
The overall scores are close — 6 versus 5 — because some differences go in Tamil’s favour and others go in Kerala’s favour. But on the most critical factor — Rajju — the results are completely opposite.
Tamil says Rajju passes. Kerala says Rajju fails.
This is not a calculation error. This is two traditions following different rules.
Why Do These 5 Factors Differ? The Technical Reason
Here is the specific reason each factor gives a different result.
1. Rajju — The Most Critical Factor
Rajju checks longevity of the spouse. Same Rajju group for both partners is considered strongly inauspicious in South Indian tradition. It is treated as a near deal-breaker regardless of other scores.
Tamil and Kerala traditions divide the 27 nakshatras into 5 Rajju groups — but they assign different nakshatras to different groups.
In the Tamil tradition, Bharani and Chitra fall in different Rajju groups — so this couple passes Rajju.
In the Kerala tradition following Prashna Marga, both Bharani and Chitra fall in the Kantha group — so this couple fails Rajju.
Same nakshatras. Two traditions. Two completely opposite verdicts on the most important factor.
This is the most significant practical difference between Tamil and Kerala Porutham.
2. Sthree Deergha — Different Distance Threshold
Sthree Deergha checks the welfare of the bride by measuring how many nakshatras apart the boy and girl are.
Tamil tradition: The boy’s nakshatra counted from the girl’s must be more than 13 stars away to pass.
Kerala tradition: The same distance must be more than 16 stars away to pass.
For this couple the nakshatra distance is 16 — which passes the Tamil threshold of more than 13 but does not pass the Kerala threshold of more than 16.
Same distance. Different thresholds. Different result.
3. Yoni — Different Scoring Method
Yoni checks physical and instinctive compatibility based on the animal symbol associated with each nakshatra.
Tamil tradition uses an animal compatibility table. Friendly animals give partial marks. Enemy animals give zero. The same animal gives full marks.
Kerala tradition is stricter — it requires the same animal AND the girl’s nakshatra must have a female Yoni gender and the boy’s nakshatra must have a male Yoni gender. Only this specific combination gives full marks. Everything else fails.
For this couple Tamil gives a partial score because the animals are not outright enemies. Kerala gives zero because the gender condition is not met.
4. Rasi Porutham — Different Method Entirely
Tamil tradition calculates Rasi Porutham based on the relationship between the ruling lords of both Moon signs. If the lords are friends the match passes. If neutral it gets partial marks. If enemies it fails.
Kerala tradition uses a positional method instead — it checks where the two Moon signs fall relative to each other on the zodiac wheel. A 6/8 position fails. A 2/12 position gets partial marks. All other positions pass.
For this couple the Tamil lord relationship gives a partial score. But the Kerala positional check gives a full pass because Aries and Libra are in a 1/7 position which is fully auspicious.
5. Rasi Athipathi — Different Treatment of Neutral Planets
This factor also checks the friendship between the ruling lords of both Moon signs — but with a different scoring rule.
Tamil tradition: Neutral lord relationship = 0.5 points (partial).
Kerala tradition: Neutral lord relationship = full marks (1 point).
For this couple the lords are neutral — so Tamil gives half marks and Kerala gives full marks.
So Which System Should You Follow?
The honest answer is: follow the tradition of your family and region.
If you are a Tamil family in Tamil Nadu or have a family astrologer who follows the Tamil tradition — use Tamil Porutham as your primary reference.
If you are a Kerala family or your astrologer follows the Prashna Marga tradition — use Kerala Porutham.
Both are classically valid. Neither is wrong. They are different traditions that have been followed for centuries in their respective regions.
The problem only arises when:
- You check one system and not the other
- Your family is from a region that follows Tamil rules but the astrologer uses Kerala rules without telling you
- A website calculates Tamil Porutham but labels it simply as “Porutham” without specifying which tradition
- A North Indian family using Ashta Koota has no idea either Porutham system exists
Why Checking Both Together Makes Sense
If your match shows Rajju pass in Tamil but Rajju fail in Kerala — what do you do?
At minimum you need to know both results exist and understand why they differ. You cannot make a confident decision based on only one system’s output when the two traditions give opposite verdicts on the most critical factor.
This is especially relevant for:
- Cross-regional matches where one family follows North Indian Ashta Koota and the other follows South Indian Porutham
- Matches where families from different South Indian states are involved
- Anyone who wants to show a complete compatibility document to an astrologer for further analysis
A report that shows all three systems — Ashta Koota, Tamil Porutham and Kerala Porutham — side by side gives you and your astrologer the complete picture in one place.
You can see exactly where the systems agree, where they differ, and which factors are causing the difference.
The Broader Point About Marriage Compatibility
It is worth stepping back here.
Tamil and Kerala Porutham — even combined with Ashta Koota — cover approximately 25% of complete horoscope compatibility analysis.
The remaining 75% requires individual horoscope analysis — the promise of marriage in each chart, the strength of the 7th house and its lord, Venus and Jupiter conditions, dasha timing, Graha Milan and Bhav Milan analysis.
This is why even a match that passes all three systems needs professional astrologer review. And why a match that fails one system is not automatically rejected — the individual charts and the remaining analysis may tell a very different story.
The Porutham score is the starting point. It is not the conclusion.
Get a Complete 3-System Compatibility Report
If you want to see exactly how your match performs across all three systems — Ashta Koota, Tamil Porutham and Kerala Porutham — with every dosha checked and every cancellation rule applied, you can get a detailed PDF report for ₹299. This is a system-generated compatibility report — not a personal consultation. It gives you the complete matching picture across all three traditions in one document. Think of it as the foundation — the data your astrologer needs to do the deeper analysis. For a complete horoscope compatibility consultation including individual chart analysis, marriage promise, dasha timing and Graha Milan — that is a separate service entirely.
The report includes both charts displayed in North and South Indian formats, Vimshottari Dasha comparison, Paap Samya analysis, Shadastaka analysis, Nadi Dosha with cancellation rules, Mangal Dosha checked from all three reference points, and remedies for every dosha found.
You can also check your Rajju Porutham here using my free calculator.
Astrologer Ashish Desai has 25+ years of Jyotish study and 15+ years of professional consulting experience. He is the creator of Kundali Milan Pro — the only Android app covering Ashta Koota, Tamil Porutham and Kerala Porutham with correct classical rules for both systems.
Research references: Prashna Marga (Kerala Porutham rules), Gayatri Devi Vasudev — The Art of Matching Charts, Mridula Trivedi — A Compendium of Marriage.