The Nadi disagreement between two is called as Nadi Dosha and generally regarded as the strict no for the marriage.
Nadi is one of the important Kootas in matching making for the purpose of marriage in Vedic Astrology . It indicates health compatibility & out of 36 points in marital match making 8 points are given to Nadi . Nadi has given maximum points and hence regarded as the most important factor by astrologers.
There are three different Nadis Adi / Adhya / Aadh (start), Madhya (middle) and Antya (end) and they represent "Prakriti" of an individual that is his/her body constitution. As per Ayurveda there are three different Prakritis- Vaat , Pita & Kapah The Nadi Adi, Madhya and Antya Nadi are equivalent to Vaat , Pita & Kapah respectively .
The exact Nakshatra based classification is as follows—
1) ADI / Adhya / Aadh Nadi : People born in Ashwani , Ardhra , Punarvasu , Uttaraphalguni , Hasta , Jyeshta , Moola , Satabisha & Poorvabhadrapada have Adi Nadi
2) Madhya Nadi : People born in Bharani , Mrigasira , Pushya , Poorvaphalguni , Chitra , Anuradha , Poorvashadha , Dhanshita & Uttarabhadrapada have Madhya Nadi .
3) Antya Nadi : People born in Kritika , Rohini , Aslesha , Magha , Swati , Vishakha , Uttarashadha , Sravana & Revati Nakshtras have Antya Nadi . Nadi Dosha exists if proposed husband and wife are having same Nadi. Scientifically speaking having same Prakriti means their offspring will be physically weaker. If Nadis of proposed husband and wife are different it is only then marriage is recommended so they may have physically stronger children. However it is not accurate to reject a proposal for marriage just because the girl & boy have same Nadi as in the Shastras its mentioned that if Nadis are same then also some other things are to be watched and then the result should be predicted. Below are some points to be checked .
1) The Rashi of male & female are same but the Nakshatra are different, then no Nadi dosha.
2) The Nakshatra are same and the Rashis are different, then no Nadi dosha.
3) The Rashis are same and Nakshatras are same but the pada of Nakshatra are different then no nadi dosha.
4) The 5th House of Lagan kundali of both girl & boy should be checked as House No- is considered house of Children.
5) The placement of Jupiter in both girl & boy's horoscope should be checked. Jupiter is considered as Putrakarak planet
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