Nada Bindu Upanishad

Nadabindu Upanishad
Opening verses of the Upanishad metaphorically describe soul as a migrant bird
Devanagari	नादबिन्दू
IAST	Nādabindu
Title means	Pinpoint Concentration due to nada.
Date	~100 BCE to 300 CE
Type	Yoga
Linked Veda	Rigveda or Atharvaveda
Chapters	1
Verses	20, 56
Philosophy	Yoga, Vedanta

The Nadabindu Upanishad (Sanskrit: नादबिन्दु उपनिषत्, IAST: Nādabindu Upaniṣad) is an ancient Sanskrit text and one of the minor Upanishads of Hinduism. It is one of twenty Yoga Upanishads in the four Vedas. It also known as Amitra Nada Bindu Upanishad.

The text 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 word Nada, being a Vedic terminology refers to as the unstruck sound or "Anahata Nada" which is reported as a thin buzzing sound being heard in right ear, and upon whom meditating, a person attains the "turya" of meditation easily. It is said that this sound has its source in the Anahata Chakra( the fourth Chakra in vedic terminology). Other religions also have same terms for it like "shabad", "Word" etc. This scripture tells how to listen to that sound so that to attain a deep state of meditation.

The relative chronology of the text is placed by Mircea Eliade with the ancient Yoga Upanishads. He suggests that it was composed in the same period when the following texts were composed – Maitri Upanishad, the didactic parts of the Mahabharata, the chief Sannyasa Upanishads and along with other early Yoga Upanishads such as Brahmabindu, Brahmavidya, Tejobindu, Yogatattva, Kshurika, Yogashikha, Dhyanabindu and Amritabindu. These and the Nadabindu text, adds Eliade, were composed earlier than the ten or eleven later yogic Upanishads such as the Yoga-kundali, Varaha and Pashupatabrahma Upanishads.