Śivasaṃhitā 5.109

The anāhatacakra holds a pivotal position in yoga’s subtle anatomy: it is the fourth of the principal energetic centers and resides in the heart region. Its name, meaning ‘unstruck’ or ‘unpercussed’, refers to the primordial sound that resonates there without friction or external cause — a sound that exists prior to and beyond ordinary language.

The text specifies that this lotus contains Sanskrit letters from ka to ṭha, twelve consonants from the velar and palatal series of the Devanāgarī alphabet, distributed across twelve petals (dvādaśāra). This correspondence between phonemes and petals is not ornamental: in the Tantric tradition, each petal vibrates with a specific energy of sacred speech, making the heart a living sonic matrix.

The heart as the seat of the ātman is a concept running through the oldest Upaniṣads. The Chāndogya Upaniṣad describes the inner space of the heart (dahara ākāśa) as the dwelling place of Brahman. The Śivasaṃhitā inherits this vision and enriches it with the Tantric cartography of the cakras, integrating Vedāntic philosophy with ritual practice into a coherent contemplative system.