In Tamil Nadu, the texts are mainly written in Vatteluttu, which is an ancient Tamizh (Tamil) script. They were written by a Rishi called Agathiyar who had a highly developed consciousness. These ancient records of providence were made famous by practitioners around the Vaitheeswaran Temple in the state of Tamil Nadu. First, the Naadi palm leaves are located based on the thumb impressions (right for men, left for women). These Naadi leaves were initially stored in the premises of Thanjavur’s Saraswati Mahal Library in Tamil Nadu. The British colonialists later showed interest in the Naadi leaves concerned with herbs and medicine, future prediction, etc. Some leaves got destroyed and the remaining were auctioned during the British rule. These Nadi leaves were obtained by the families of astrologers at the Vaitheeswaran Temple and have been passed down the years from one generation to the other.

There is also another set of astrologers claiming that the content written in the palm leaf is conversation between Shiva and parvathi. This is called Shiva nadi josiyam. The basic concept of Nadi Astrology is “Nadi” (nāḍi). There are 150 Nādis in a sign or Rāshi (Rāsi), one sign is 30 degrees of zodiac. Twelve signs of zodiac grouped into three categories : Movable (Chara), Fixed (Sthira) and Dual (Dvisvabhāva) signs Nomenclature of 150 Nādis is peculiar to each of these three types of signs. There are 1800 Nādis in 360 degrees. Numbers and names of Nādis are identical among all four Chara signs. Among all four Sthira signs, Numbers and names of Nādis are identical, but numbering is different from those in Chara and Dvisvabhāva signs. Similarly, numbering of Nādis in all four Dvisvabhāva signs are identical among themselves, but different from Chara or Sthira signs. For instance, the first Nādi in Chara signs such as Aries is Vasudhā Nādi, but in Sthira sings the order is reversed and Vasudhā is 150th Nādi. In Dvisvabhāva signs such as Gemini, Vasudhā is 76th Nādi; that is, from the middle of 150. Thus, there are 450 distinctive names and numbers in full zodiac. Nādi texts use this concept of Nādi as the basic unit for prediction. That is why they are called “Nādi granthas”.