Does Gana matter in marriage?

Astrology says that normally marriage can be fixed between Dev and Manushya Gana. But Rakshasa Gana is an inauspicious Gana for these 2 Ganas. It is not considered a good match if a Rakshasa Gana person marries a Deva or Manushya gana person.

How many Gunas match is good?

For approving a marriage, there must be not less than 18 Guna matches between the bride and the groom's horoscopes. If the matching Gunas are less than 18, then the proposed match is not approved. If 18 to 25 Gunas match, then it is demed as a good marriage.

Can Deva Gana and Rakshasa Gana get married?

How do you match Gana to marriage?