The use of mantras or mystic syllables or formulae, as an aid to upāsanā or meditation is wide-spread in Hinduism. Though Brahman, the ultimate Truth or the Absolute is one and one only, its manifestations however, can be innume-rable. As is declared in the Bhagavadgītā (4.11; 7.21) God responds to the prayers of his devotees in and through any form the devotee chooses. Over the millennia, the ṛṣis of the Vedas, the purāṇas and the tantras (secondary scriptures) of the various cults have given us a large number of deities, both male and female, for our upāsanā and spiritual upliftment. If it is remembered that all these deities, though with different names and forms, are, all the same, the various manifestations of that God—like the chocolate dolls being chocolate only and hence all tasting sweet—there can be no confusion or conflict in the minds of the votaries.
Every deity has a tantra or a philo-sophy and associated rituals, a yantra or a geometrical form and a mantra or a sound-form. The physical form of the deity is described in its dhyānaśloka (hymn of meditation) which is of great help in actual meditation.
The mantras are of various types, the most common form being the one having three or four parts: praṇava or Oṁ, the bījākṣara or the bījāmantra, the name of the deity in the caturthī-vibhakti or dative case and the word namaḥ indicating obeisance. For eg., consider the well-known mantra of Śiva—Oṁ namaś-śivāya, (‘Om, obeisance to Śiva!’) Here, of course, the bījākṣara, the seed-letter, is missing.
The bījamantra, which is generally monosyllabic and hence called ‘bijākṣara’ (akṣara = letter) also, is, as its very name indicates, a ‘seed-formula,’ containing the essence of the deity in itself. This will gradually get evolved by an assiduous practice of its repetition with faith and devotion, even as the tree evolves out of its seed by proper cultivation. Hence the aptness of the term ‘bīja’ to it.
Every deity, even the different aspects of the same deity, have different bījamantras which are kept a secret, to be handed down in the oral tradition from the guru to the disciple at the time of dīkṣā or initiation into spiritual life.
Some of the more common bīja-mantras are: hauṁ (for Śiva), duṁ (for Durgā), krīṁ (for Kālī), śrīṁ (for Lakṣmī) aiṁ (for Sarasvatī), klīṁ (for Kāmadeva or Kṛṣṇa), gaṁ (for Gaṇapati) and so on.
The readers of the tāntric works are however warned not to practise their repetition unless it is ceremonially received from a qualified guru.