The suffix 'tra' in Sanskrit means instrument. Yantras are the
geometrical form of a divinity in the tantrik tradition. Images (murtis) and
mantras are other, more gross and subtle, representations. Yantras can be
drawn, engraved or painted on a variety of substances. The classical eight
tantrik surfaces are gold, silver, copper, crystal, birch, bone, hide (which
can include any type of paper), and Vishnu stone (shalagrama).

The yantra shown left is for
Kali, and can
be used to illustrate the basic geometrical concepts used. The point or
bindu at the centre, generally represents the deity, or sometimes Shiva and
Shakti united. The triangle normally represents the three gunas, or in the
case of the tantrik tradition, the three bindus.

Triangles usually face downwards in the case of female yantras and upwards
in male yantras. There are exceptions - the
Shri Yantra
is one such. Triangles are often surrounded by enclosing circles and a group
or groups of petals, in which are the attendants of the Devis or Devas. See
the Mahamrityunja
yantra for a complete example. Finally, the whole is often enclosed in a
bhupura, a word which means earth-city. These are the enclosing walls,
fenced by the guardians of the directions and the intermediate directions (dikpalas).
Some traditions use the yantra in puja from the outside inward, and others
from the inside outward, depending on the nature of the deity. There are
many other yantras which have their own individual shapes, often used in
magic (prayoga). One such shown here is an akarshana (attraction) yantra
from the magical Kamaratnatantra.

A yantra is only truly vitalised when it is engraved with the bija and
other mantras and surrounded with the matrikas, or letters of the Sanskrit
alphabet. Before use, it must be installed with life, a rite called
Pranapratishta (establishing breath). The following is an example.

Installation of Life in a Shri Yantra

Before any yantra is a suitable object for puja, it must be given life (pranapratishta).
The following, from Nityotsava, describes the process. This, process,
incidentally, also holds true for initiation of a candidate into Shri Vidya.
The rite installs the
35 tattvas
into the yantra. It also gives the yantra the full set of senses and the
Antahkarana, or subtle body. It is said that engraving a Shri Yantra on gold
is said to hold good for life, on silver for seven years. The process also
imbues the yantra with the matrika, the letters of the Sanskrit alphabet
which are the goddess as sound.

The Yantra Gayatri is Yantrarajaya Vidmahe Mahayantraya Dhimahi Tanno
Yantrah Prachodayat.

Brahmna-Vishnu-Maheshvara are the Rishis of this great mantra installing
life into the Shri Yantra; Rg, Yajur, Sam and Atharva are the Metres;
Consciousness is the Devata; Am is the Bija, Hrim the Shakti, Krom the
Kilaka. The application is installation of life into the Shri Chakra.

Aim Hrim Shrim Am Kam Kham Gam Gham Nam to Earth, Water, Fire, Air and
Aether, Am to the thumbs Namah.

3 Im Cham Ccham Jam Jham Nam to Sound, Touch, Sight, Taste, Smell Im to the
index fingers Namah.

3 Um Tam Tham Dam Dham Nam to Hearing, Touch, Eyes, Tongue, Nose Um to the
middle fingers Namah.

3 Um Tam Tham Dam Dham Nam to Speech, Hands, Feet, Genitals, Anus Aim to the
ring fingers Namah.

3 Om Pam Pham Bam Bham Mam to Talking, Giving, Moving, Enjoying, Excreting
Aum to the little fingers Namah.

3 Am Yam Ram Lam Vam Sham Sham Sam Ham Lam Ksham to Manas (mind), Buddhi
(intellect), Ahamkara(ego), Thought, Inner Cause, Ah to the palm and back of
the hands Namah.

(Thus Heart &c. Nyasa)

Aim Hrim Shrim Om Am Hrim Krom Yam Ram Lam Vam Sham Sham Sam Haun Ham Sah
may Life exist here in the Shri Chakra!

3 Om Am Hrim Krom Yam Ram Lam Vam Sham Sham Sam Ham Ham Sah my individual
existence be here in the Shri Chakra!

3 Om Am Hrim Krom Yam Ram Lam Vam Sham Sham Sam Ham Ham Sah may all the
senses be here in the Shri Chakra!

3 Om Am Hrim Krom Yam Ram Lam Vam Sham Sham Sam Haum Ham Sah, may Speech,
Mind, Eyes, Ears, Tongue, Nose, Breath come inside this Shri Chakra! May
Happiness stay long here! Svaha.

Internal meditations

Yantras may also be visualised internally. That, for example, is the case
with the Shri Yantra, with the different mandalas starting at the base of
the spine and going to the top of the head.

Different rituals exist for the purification of a yantra for the eight
materials mentioned above. This which follows is drawn from the
Devirahasya.
Shiva is the Seer, Trishtubh the Metre, Parashakti the Devata, Shrim the
Bija, Hrim the Shakti and Klim the Peg. The application is the purification
of the given yantra.

After doing hand and limb nyasa, one should meditate on the throne of the
given Devi as being in one's heart. One should draw, engrave, or paint the
yantra, and place it on a gold colour pedestal, installing breath into it.

It can be smeared with Kunda, Gola or Udbhava flowers or with the eight
scents. The mantra differs for each material:

Gold: Aim Sauh Aim Sauh Chakreshvari Yantram Sauvarnam Shodhaya Shodhaya
Svaha. (Aim Sauh Aim Sauh, O Lady of the Chakra, Purify! Purify the gold
yantra! Svaha)

Silver: Om Rum Om Rajatam Yantram Shodhaya Shodhaya. (Om Rum Om Purify!
purify the silver yantra)

Copper: Om Krom Om Strim Om Krom Tamreshvari Yantram Me Shodhaya. (Om
Krom Om Strim Om Krom, O Lady of Copper, purify the copper yantra for me!)

Crystal: Om Shrim Hrim Om Kulambike Shodhaya Shodhaya.

Birch bark: Om Hum Shrim Hrim Prim Ruddhesvari Parayantram Shodhaya. (Om
Hum Shrim Hrim Prim O Lady of Trees, purify the yantra!)

Bone: Om Aim Klim Sauh Kapalamalini Yantram Shodhaya Svaha. (Om Aim Klim
Sauh O Thou garlanded with skulls, purify the yantra! Svaha)

Hide: Om Shrim Om Aim Klim Citasane Yantram Shodhaya Svaha. (Om Shrim Om
Aim Klim O Thou Whose seat is the Pyre, purify the yantra! Svaha)

Vishnu Stone (Shalagrama): Om Hsau Aim Sauh Klim Shrim Shrim Nitye Vishnu
Shila Yantram Shodhaya. (Om Hsau Aim Sauh Klim Shrim Shrim, O Eternal One,
purify the Vishnu Stone Yantra )

After using the appropriate mantra, the yantra should be placed on a
pedestal (pitha), and bathed with the substances previously described,
whilst the appropriate root mantra is recited. One should then offer scent
and flowers, and should worship the appropriate Devi in the usual form
within the yantra. This all should be done at night.

Carrying a Yantra. This is considered to be a highly potent way of
concentrating magical power. The time to do this is during an auspicious
astrological period. The yantra should be drawn using the eight Kaula
perfumes. Outside the yantra the root mantra should be written.

On the outside of this the armour (kavacha)
and 1000 names should be written. The Devi should be invoked into the yantra
in due form. All good substances are to be used. The yantra is then entwined
with gold and silver thread, and placed into a metal holder and may be worn
on the person.

Yantras should always be used on the level. If drawn on paper the colours
preferable are red, orange, yellow or a combination of these. A yantra
without bija mantras is dead. They can be drawn to whatever size is
required.

The two main types of yantra are Bhu and Meru. The former is flat, two
dimensional, the latter is of pyramidal form. When not in use they should be
stored carefully. Metal ones should be regularly cleaned to prevent
corrosion &c. In worship they should be placed level on a pedestal or pitha.
This may be as ornate or as simple as required.