Idangai or the left hand is a caste-based division of communities in Tamil Nadu that was in vogue from ancient times right up to the 19th and even the early decades of the 20th century AD. Since India's independence, the differences have practically vanished. The corresponding division is Valangai.
From ancient times, there was intense rivalry between the left-handed and right-handed factions. The Idangai faction was numerically inferior to the Valangai and comprised six castes as opposed to the sixty of the Valangai. It was also unclear as to which castes constituted each faction. Some castes considered to be left-handed in some areas were regarded as right-handed in others and vice versa. Roughly speaking,the Valangai or right-handed faction was made up of castes with an agricultural basis while the Idangai was made of metal workers, weavers, etc. i.e. castes involved in manufacturing.The core groups in Idangai were the five castes called Anchalar/ Panchalar. ie-
Further castes were added at various times.
The Valangai faction was better organized, politically, than the Idangai.
- Alcock, Susan E.; D'Altroy, Terence N.; Morrison, Kathleen D.; Sinopoli, Carla M. (2001), Empires: Perspectives from Archaeology and History, Cambridge: Cambridge University Press, p. 269, ISBN 978-0-521-77020-0
- Ghurye, G. S. (1991) , Caste and Race in India, Bombay: Popular Prakashan
- McGilvray, Denis B. (1982), Caste Ideology and Interaction, Cambridge: Cambridge University Press, ISBN 978-0-521-24145-8
- Siromoney, Gift (1975), "More inscriptions from the Tambaram area", Madras Christian College Magazine, Madras Christian College Magazine, 44, retrieved 21 September 2008
- Yandell, Keith E.; Paul, John Jeya (2000), Religion and public culture: Encounters and Identities in Modern South India, Routledge, ISBN 978-0-7007-1101-7
- Brimnes, Niels (1999). Constructing the Colonial Encounter: Right and Left Hand Castes in Early Colonial South India. Psychology Press. ISBN 9780700711062.
- Dirks, Nicholas B. (2001). Castes of Mind: Colonialism and the Making of Modern India. Princeton University Press. ISBN 9780691088952.
- Epstein, Trude S. (1962). Economic Development and Social Change in South India. Oxford University Press.
- Flueckiger, Joyce Burkhalter (2013). When the World Becomes Female: Guises of a South Indian Goddess. Indiana University Press. ISBN 9780253009609.
- Mines, Mattison (1984). The Warrior Merchants: Textiles, Trade, and Territory in South India. Cambridge University Press. ISBN 9780521267144.
- Mines, Mattison (1994). Public Faces, Private Voices: Community and Individuality in South India. University of California Press. ISBN 9780520914599.
- Mukund, Kanakalatha (2005). The View from Below: Indigenous Society, Temples, and the Early Colonial State in Tamilnadu, 1700-1835. Orient Blackswan. ISBN 9788125028000.
- Seshan, Radhika (2012). Trade and Politics on the Coromandel Coast: Seventeenth and Early Eighteenth Centuries. Primus Books. ISBN 9789380607252.
- Sharma, Yogesh, ed. (2010). Coastal Histories: Society and Ecology in Pre-modern India. Primus Books. ISBN 9789380607009.