Yantra is a Sanskrit word, derived from the Sanskrit root, yam or yantrati, meaning to control or restrain. So any mystical diagram or instrument with divine powers, and used for this purpose is a yantra. A yantra is a synergistic and transcendental system and depicts both macrocosmic and microcosmic forces acting together in the form of control and liberation. It is a set of power diagrams, which are visual representations of magical intentions and ideas. It is a spiritual system of divine energy, which is in harmony with the larger universe and focused on the primordial center, aiming at the unity of self and cosmos.
All knowledge in India has its roots in Vedas. Rigveda imparts basic knowledge of everything in the universe. Yajurveda transforms this knowledge to the practical form known as karma. Samaveda converts this karma to ecstacy. When karma becomes pure and dedicated to the Almighty, liberation or moksha is achieved. Tantra vidya is a part of Karma yoga. A man leads a spiritual life with the help of mantras and symbolic forms of the almighty. Yantra vidya is a part of Tantra vidya. It is believed that gods shower blessings on those, who perform rituals and sacrifice with dedicated offerings. Men offer puja to gods, who in turn grace men with plenty of wealth and physical comforts. Yantra vidya is thus a miniature form of the God concept.
Manoradha kharanyathra Niyanthryenthe thapodhana
Kamakrodhadi doshanva Deergha dukha niyanthranath
According to this shloka, from the ancient classic Sharadathilakam, a yantra performs two types of functions. It controls the mental activities of a person. It also gives him protection from all sorts of evil effects. Yantra dharma is very much same to Eshwara dharma or Vigraha dharma. Yantras can be considered as vigrahas or Idols and are vessels for storing divine power. They control the mind and deity - this is Yantraphalam or the function of the yantra.
Yantra is referred to as chakra in Tantrik language. Tantra is the macro or sthoola manifestation of deities. The entire power of the Yantra is concentrated at a certain centre and is then distributed in fixed proportion everywhere. This is the mode of Yantra motion. Preparation of a yantra is based on the Baahya puja system. The yantra is drawn on a flat background on a bhojpatra, palm leaf, betel leaf, panchaloha, gold, silver, copper, panch dhatu, crystal, birch, bone, hide, shaligrama or even paper. The surface on which the yantra is drawn is considered to be prapancha or kshetra, symbolizing the universe, with all its movable and immovable things within. The universe, kshetra and human body are all the same. If a human body is flattened, we get a Yantra. Everything in a Yantra can be found in a human body and everything in a human body can be seen in the universe.
Signification of Yantra elements