Sadhana in the context of Jnana yoga

A charnel ground (Sanskrit: श्मशान; IAST: śmaśāna; Tibetan pronunciation: durtrö; Tibetan: དུར་ཁྲོད, Wylie: dur khrod) is an above-ground site for the putrefaction of bodies, generally human, where formerly living tissue is left to decompose uncovered. Although it may have demarcated locations within it functionally identified as burial grounds, cemeteries and crematoria, it is distinct from these as well as from crypts or burial vaults.

In a religious sense, it is also a very important location for sadhana and ritual activity for Indo-Tibetan traditions of Dharma, particularly those traditions iterated by the Tantric view such as Kashmiri Shaivism, Kaula tradition, Esoteric Buddhism, Vajrayana, Mantrayana, Dzogchen, and the sadhana of Chöd, Phowa and Zhitro, etc. The charnel ground is also an archetypal liminality that figures prominently in the literature and liturgy and as an artistic motif in Dharmic Traditions and cultures iterated by the more antinomian and esoteric aspects of traditional Indian culture.

Sadhu (Sanskrit: साधु, IAST: sādhu (male), sādhvī or sādhvīne (female), also spelled saddhu) is a religious ascetic, mendicant or any holy person in Hinduism and Jainism who has renounced the worldly life. They are sometimes alternatively referred to as yogi, sannyasi or vairagi.

Sādhu means one who follows a path of sadhana (spiritual discipline). Although the vast majority of sādhus are yogīs, not all yogīs are sādhus. A sādhu's life is solely dedicated to achieving mokṣa (liberation from the cycle of death and rebirth), the fourth and final aśrama (stage of life), through meditation and contemplation of Brahman. Sādhus often wear simple clothing, such as saffron-coloured clothing in Hinduism and white or nothing in Jainism, symbolising their sannyāsa (renunciation of worldly possessions). A female mendicant in Hinduism and Jainism is often called a sadhvi, or in some texts as aryika.

Yantra (Sanskrit: यन्त्र, romanized: yantrá, lit. 'machine, contraption') is a geometrical diagram, mainly from the Tantric traditions of the Indian religions. Yantras are used for the worship of deities in temples or at home; as an aid in meditation; and for the benefits believed given by their occult powers based on Hindu astrology and tantric texts. They are also used for adornment of temple floors, due mainly to their aesthetic and symmetric qualities. Specific yantras are traditionally associated with specific deities and/or certain types of energies used for accomplishment of certain tasks or vows that may be either materialistic or spiritual in nature. They become a prime tool in certain sadhanas performed by the sadhaka, the spiritual seeker. Yantras hold great importance in Hinduism, Jainism, and Buddhism.

Representations of the yantra in India have been considered to date back to 11,000–10,000 BCE. The Baghor stone, found in an Upper Paleolithic context in the Son River Valley, is considered the earliest example by G. R. Sharma, who was involved in the excavation of the stone (it was dated to 25,000–20,000 BCE). The triangular stone, which includes triangular engravings on one side, was found daubed in ochre in what was considered a site related to worship. Worship of goddesses in that region was found to be practiced in a similar manner to the present day. Kenoyer, who was also involved in the excavation, considered it to be associated with Shakti. This triangular shape looks very much similar to Kali Yantra and Muladhara Chakra.