The Nadabindu Upanishad (IAST: Nādabindu Upaniṣad) or  Amitra Nada Bindu Upanishad is an ancient Sanskrit text which belongs to the twenty Yoga Upanishads of the four Vedas.

It is also one of the 5 Bindu Upanishads (Tejo-Bindu, Amrita-Bindu, Dhyana-Bindu, Brahma-Bindu) attached to the  Atharvaveda.

The text of the upanishad exists in two significantly different versions, the North Indian and the South Indian. These manuscripts are respectively attached to the Atharvaveda or to the Rigveda.

The manuscripts of Nadabindu discovered in different parts of India, partially vary in the Kala list. For example, the Calcutta version differs from Poona edition by replacing Dhriti with Dhruva, and Mauni for Nari.

== Content ==

The Nada-Yogins  practice meditations on the Nada or Shabda or on the  highest Pranava, eventually with a mantra like OM (or Aum) as for example in Yoganandas Kriya Yoga.

The Nadabindu Upanishad sees the Nada as the bird Hamsa, as which the Atman appears. The parts of the body of this bird are the 3 letters of the word AUM and the three gunas of the Samkhya doctrine.

The teaching goes beyond the Brahman : What is beyond that is the Para-Brahman, the pure all-penetrating, beyond the Kalas, the ever-shining and the source of all the Jyotis (light), should be known.

Dharma (ethics) is a requirement for a Yogi life. It it is notable for describing Om symbol with twelve moras instead of three and half moras commonly found in ancient Indian literature.

The yogin contemplates on Omkara as Hamsa, in twelve Kalas or variations of the four matras (intonations). The variation is produced by the three svara (note on the musical scale), namely Udatta, Anudatta and Svarita. Chapter 2 describes the sounds heared during contemplation.

The twelve Kalas, according to Nadabindu text, are Ghosini, Vidyunmali, Patangini, Vayuvegini, Namadheya, Aindri, Vaishnavi, Sankari, Mahati, Dhriti, Nari and Brahmi.

The text suggests that a yogin should contemplate and be absorbed in the Om with these Kalas, as it leads one to knowledge of Atman or Self, helps him overcome three types of Karma. The text also refers to the Vedanta theory of Ajnana (ignorance) as the cause of bondage. It suggests that a yogin should listen to his inner voice in Siddhasana.

• The Practice of Nada Yoga: Meditation on the Inner Sacred Sound ,  Baird Hersey
• Sonic Theology: Hinduism and Sacred Sound , von Guy L. Beck
• Thirty minor upanishads , K. Aiyar, 1914
• Nada Bindu Upanishad online, Aiyar
• Nadabindu Upanishad, (Rigveda) translated by the Kumbakonam, Theosoph. Society
• Message of the Upanishads, B. B. Paliwal

== Weblinks ==

* Aiyar, K. Narayanasvami (trans.), NĀḌABINḌU-UPANISHAḌ OF ṚGVEḌA in Thirty Minor Upanishads, 1914 -online