This page explains how the Kataka and Simha rashi pairing is read in Sinhala porondam and Tamil porutham, in both directions. The rashi here is the moon sign (chandra rashi) in the sidereal zodiac used in Sri Lanka, not the newspaper sun sign. The rashi results are only a starting point, because the full match depends on the two birth stars.
What does the rashi count mean for Kataka and Simha?
The rashi count is taken from the bride's moon sign to the groom's. When the bride is Kataka and the groom is Simha, the groom's sign is the 2nd from the bride's. In this direction, rashi porondam is not obtained in the Sinhala method, and rasi porutham is also not obtained in the Tamil method.
When the bride is Simha and the groom is Kataka, the count becomes 12. Here the Sinhala rashi porondam is partly obtained, while the Tamil rasi porutham is obtained. The same two signs therefore give different rashi results depending on which partner holds which sign, which is why the direction always matters.
Are the Moon and Sun friendly rashi lords, and what about vashya?
Kataka is ruled by the Moon and Simha by the Sun. The calculator treats these two lords as mutual friends, so rashyadhipathi porondam (Sinhala) and rasi adhipathi porutham (Tamil) are obtained in both directions. This is a steady, positive point for the pairing whichever way round it falls.
Vashya, the factor describing a natural sense of mutual attraction between the signs, works differently. For Kataka and Simha, vashya porondam and vasya porutham are not obtained in either direction. This is one item among many, and on its own it does not decide a match; the birth-star factors carry much more weight.
Why do the birth stars decide the real match?
Each rashi contains parts of several nakshatras, and each nakshatra has four quarters (padas). For one direction of this pairing there are 81 possible star-quarter combinations, and the outcomes vary widely between them.
With a Kataka bride and Simha groom, none of the 81 combinations reach 8 of 10 porutham, about 74% come out weak on the Tamil count, and about 5% pass Sinhala porondam (excluding the weekday factor). With a Simha bride and Kataka groom, about 25% reach 8 of 10, about 49% are weak on the Tamil count, and about 99% pass Sinhala porondam. No combination in either direction shows a Tamil rajju clash.
How should families use this result?
The rashi-level picture is useful background, but it cannot tell you how a particular couple matches. Two people with the same pair of moon signs can have very different results once their exact birth stars and quarters are known.
For a meaningful reading, use the Lakpura porondam and porutham calculator with full birth details: date, exact time and place of birth for both partners. This lets the calculator identify each person's nakshatra and pada and work through every factor properly.
For marriage decisions, it is wise to take the full results to a family astrologer, who can look at the complete horoscopes and the wider family context together.
Read the Kataka horoscope and the Simha horoscope, or check two exact birth charts with the porondam calculator.