01What is nakshatra porutham?
Porutham (பொருத்தம், "agreement") is the Tamil almanac's method of comparing two horoscopes, and it is a different system from the thirty-six-point Ashtakoota used across the north, not a variant of it. Where Ashtakoota scores eight kootas and adds the points, porutham runs ten separate tests, each met or not met, and refuses to average two of them into the rest. Both systems read the same two facts: each partner's Moon nakshatra and the rashi that Moon stands in. Both are therefore silent about everything a chart holds outside the Moon, which the classical writers on both sides say plainly.
02Which are the ten poruthams?
Dina (the star count), Gana (temperament), Mahendra (the household and the line), Stree Deergha (the long life of the wife), Yoni (the animal classification), Rasi (the Moon signs counted against each other), Rasi Adhipathi (the friendship of the two rashi lords), Vasya (the pull one nature has on another), Rajju (the five rope groups read as the limbs of one body) and Vedha (the obstruction pairs). The last two are the ones the almanac tradition grades as essential; the other eight are graded desirable, and a match is described by how many of them agree rather than by a total out of anything.
Why Rajju is read first
The five rajju groups (Pada at the feet, Kati at the waist, Udara at the stomach, Kantha at the neck and Sira at the head) divide the 27 nakshatras between them, and two partners falling in the same group is Rajju dosha. The almanac's own language treats it as one rope pulled from both ends, and traditional practice is to stop there and consult an astrologer rather than to weigh it against a good count elsewhere. This calculator therefore reports it separately instead of folding it into the tally.
Why Vedha sits beside it
Vedha means obstruction, and the almanac carries a fixed table of thirteen nakshatra pairs that obstruct each other: Ashwini with Jyeshtha, Bharani with Anuradha, Krittika with Vishakha and so on. Chitra is the single star the table leaves without a partner, so it obstructs nobody. Like Rajju, a vedha is read as decisive rather than as one test among ten, which is why both are marked essential in the result and named in the summary even when the other eight agree.
03How is porutham calculated from a nakshatra and a pada?
Three of the ten (Dina, Mahendra and Stree Deergha) are counts from one nakshatra to the other, taken inclusively from the girl's star to the boy's, which is the convention this calculator states in every row that uses it. Four more (Rasi, Rasi Adhipathi and Vasya, plus part of the reading) need each partner's Moon rashi, and that comes from the pada rather than from a separate input: the 108 padas tile the twelve rashis nine each, so a nakshatra and a pada fix the rashi exactly. Gana, Yoni, Rajju and Vedha are straight table lookups on the two nakshatras. Nothing here is estimated.
04What does a good porutham count mean?
In the tradition's terms it means the first sieve has been passed, and the writers are consistent that it is a sieve and not a judgement. Tamil practice reads seven or more of the ten as an agreeing match, five or six as one to be examined, and fewer as a reason to look at the whole chart rather than at the count, but all three of those readings are set aside if Rajju or Vedha fails, because those two are not traded. What comes after the sieve is the astrologer's work: the seventh house and its lord, the navamsa, the running dasha of each person, and the position of Mangal. A count answers none of those.
05Is porutham the same as guna milan?
No. The two systems classify the same nakshatras and rashis but ask different questions of them and reach their conclusion differently. Ashtakoota awards 36 points across Varna, Vashya, Tara, Yoni, Graha Maitri, Gana, Bhakoot and Nadi, and a total is read against bands. Porutham runs ten pass-or-fail tests and holds two of them apart from the rest. Several tests overlap in substance (Yoni, Gana and Vasya appear in both), so the two will usually agree in direction while disagreeing in wording. Where a family follows one tradition, it is the one to read; our kundli milan computes the Ashtakoota side.
06What does the tradition say about Rajju dosha?
That it is the gravest of the ten, and that the remedy is not arithmetic. The rajju groups map the nakshatras onto a body (feet, waist, stomach, neck, head), and the texts read two people in one group as competing for the same limb. Different almanacs soften it differently: some hold that the dosha is lighter when the two nakshatras are in the same rajju but on opposite sides of its ascending and descending arms, and some set it aside entirely when other poruthams are strong. This calculator reports the group each nakshatra falls in, says plainly when the two agree, and leaves the judgement where the tradition leaves it.
07Do the ten poruthams need a birth time?
They need the Moon's nakshatra and pada, and that in turn needs a birth time. The Moon crosses a pada in about six hours, so a pada recorded from a rounded birth hour is usually safe and one recorded from a half-remembered time is not. If you have the nakshatra and pada already, from a janma patri or from an astrologer, enter them directly above. If you do not, compute them first on the nakshatra calculator from a date, a time and a place. A nakshatra guessed from a name will not do for this, because the rashi is taken from the pada.
08What will this page not tell you?
It will not say what is going to happen. The ten poruthams are a classification of two Moon positions against a set of tables, and the classical writers who set those tables down treated them as a preliminary filter before a chart reading, never as a forecast and never as a verdict on two people. So this page reports what the tradition reads, names the almanac each table comes from, shows the counting so it can be checked, and stops. Where a reading is unfavourable, the tradition's own instruction is to take both charts to an astrologer, and that is the instruction the result repeats rather than one we improve on.
