The Taittiriya Upanishad is a principal Upanishad of the Krishna Yajurveda, comprising three chapters or Vallis: the Samhita Valli, the Brahmananda Valli (also called Ananda Valli), and the Bhrigu Valli. The mantras of this Upanishad are primarily found in the Ananda Valli and Bhrigu Valli, which systematically expound the doctrine of the five sheaths (pancha kosha) and the nature of Brahman as bliss (Ananda). The text begins with the famous declaration 'Om Brahmavid Apnoti Param' (Taittiriya Upanishad 2.1.1), meaning 'The knower of Brahman attains the highest.' This mantra establishes the purpose of the entire Upanishad: the realization of Brahman. The subsequent mantras describe the five koshas: annamaya (food sheath), pranamaya (vital air sheath), manomaya (mind sheath), vijnanamaya (intellect sheath), and anandamaya (bliss sheath). Each sheath is analyzed as a layer covering the Atman, with the anandamaya kosha being the innermost and closest to Brahman. The Upanishad declares 'Satyam Jnanam Anantam Brahma' (Taittiriya Upanishad 2.1.1), defining Brahman as truth, knowledge, and infinity. Another key mantra is 'Anando Brahma' (Taittiriya Upanishad 3.6.1), which identifies Brahman with bliss. The Bhrigu Valli narrates the story of Bhrigu, son of Varuna, who through tapas (austerity) realized that Brahman is annam (food), prana (life), manas (mind), vijnana (intellect), and finally ananda (bliss). The phonetics of the mantras follow the Vedic accentuation (svara) system, with udatta, anudatta, and svarita marks that are crucial for correct chanting. The beej-akshara 'Om' precedes many mantras, symbolizing the primordial sound. Traditional chanting of these mantras is believed to purify the mind, deepen understanding of the self, and lead to moksha. The recommended context for chanting is during morning or evening sandhya, with a focus on meditation on the koshas. The count is often 108 repetitions for each key mantra, or as part of a daily Vedantic study. According to the Taittiriya Upanishad itself, the one who knows the bliss of Brahman fears nothing (Taittiriya Upanishad 2.9.1). There are no specific cautions, but due to the Vedic nature, proper pronunciation and adherence to svara are emphasized. The mantras are also chanted during upanayana (sacred thread ceremony) and other Vedic rituals. The Upanishad's teachings are further elaborated in the Brahma Sutras and commentaries by Shankara.
The five sheaths (annamaya, pranamaya, manomaya, vijnanamaya, anandamaya) surrounding the Self.