Yes, Vasya Porutham can be checked if the Rasi of the bride and groom is already known. The Rasi is usually determined from the birth star or horoscope, but if someone already knows their Rasi, the matching can be checked directly. Astrologers compare the Rasi of both individuals to see whether there is a natural attraction or influence between them. If the Rasi is not known, then the birth star or horoscope details are needed first to identify the correct Rasi.