What is the meaning of Mahendra porutham?

Mahendra porutham for marriage, is the one porutham that determines the strength of the girl's mangalyam [in archaic language], or the span of life together as man and wife.

When mahendra porutham compatibility is good, it is indicated that the resultant marriages will be long, not necessarily happy [these are determined by other factors, such as vasyam, yoni, stree dheergam etc], but a long one.

Mahendra porutham calculation

If the boy's star is 4th, 10th, 13th, 19th, 22nd from the girl's star, Mahendra porutham matching is good.

Mahendra porutham - medium match If the boy's star is 7th,16th or 25th from the girl's, the porutham is only Medium.