Nadi astrology (naadi jothidam) is a form of astrology practiced in Tamil Nadu, India. It is based on the belief that the past, present and the future lives of all humans were foreseen by Hindu sages in ancient times on Palm leaves.
According to Hindu faith, thousands of years ago sages who had the power to look in the past and future of the entire universe recorded the future of people who were living and who are going to live, in the form of Tamil verses, as Palm Leaf Manuscripts. The text is written in Vatteluttu, which is an ancient Tamil script. There are different schools of thought as to the author of these leaves. They were said to be written down by different Hindu sages, who had divine revelations. Some of the sages include Agasthiya, Brighu, Kaushika, Vyasa, Kagabujandar, Valmiki and Vasishtha. This doctrine of astrology was made famous by astrologers around the Vaitheeswaran Temple in the state of Tamil Nadu and is still practiced around the temple by their descendents.
Usually the astrologer asks for the thumb impression (right hand for males and left hand for females). The astrologer then searches his repository of leaves for the seeker's classification of thumb print. Finally, the minimum possible set of matching leaves is brought. Every leaf corresponds to some individual and hence will bear the birth and kinship details of its seeker. So the seeker is asked a series of questions, based on the verses, so as to find the exact match. These questions are to be answered 'yes' or 'no'. The correct leaf for a given seeker is said to get only 'yes' responses from the seeker. Once the correct leaf is found, the astrologer tells the seeker details about his future, since they are all written in the leaf. The first chapter (kaandam) in the leaf has the general overview of its seeker's life. Then the kandams that follow this cover specific areas like Marriage, Profession, etc.