Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 8 · Marriage
विवाहः
अष्टधा राशिकूटं च स्वादूडुगणराशयः ।राशीशयोनिवर्णाख्यऋतवः पुत्रपौत्रदाः ॥ ४९६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 496.
The sign match is of eight kinds. The star, the gana (temper group), the sign, the sign lord, yoni (animal match) and varna (caste match): these six give sons and grandsons.
Simple meaning: Matching has eight parts. Six of them, matched well, give sons and grandsons.
एकराशौ पृथग्धिष्ण्ये दंपत्योः पाणिपीडनम् ।
Same sign, different stars is best for a wedding. Same star, different signs is middling.
एकर्क्षे त्वेकराशौ हि विवाहः प्राणहानिदः ।
The same star and sign may put life at risk. His star within nine of hers is not good.
द्वितीये मध्यमं श्रेष्ठं तृतीये नवके नृभम् ।
Middle if the man's star is in the second nine, best in the third. A star group is named.