Bharatanatyam, also spelt Bharathanatyam, is a Classical Dance form of South India, said to be originated in Thanjavoor of Tamil Nadu. Bharatanatyam, It was known as "Daasiyattam" since performed by Devadasies in temples of Tamil Nadu long ago. The name 'Bharatanatyam' is derived from three basic concepts of Bhava, Raga and Thaala. The modern Bharatanatyam was systematically regularized by well known 'Thanjavoor Brothers', Ponnayya, Chinnayya, Sivanandam and Vativelu. The dance is performed in the stage as Nritham, Nrithyam and Natyam. Bharatanatyam is based on the theories of the books 'Natyasaasthram' and 'Abhinaya Darpanam'. The dance form is based on 'Adavu' (steps) and 'Hasthamudra' (hand gestures). There are 64 basic 'Adavu' and they are divided into 9 parts, on which 'Thattadavu', 'Naatadavu', 'Kuthithumettadavu', 'Mandiadavu', 'Sarikkal' and 'Thattumettu' are very important. Communication is done through 'bhavabhinaya' (facial expression) and 'hasthamudra' (hand gestures). The performance starts with the prayers to God Ganapathi and worship of Nataraja Moorthi. The Music of Bharatanatyam is based on Carnatic Classical Music.