To locate the visualization in the Heart Center, the yogi should see the word at the center of the eight nerve-leaves of the Dharma Chakra of the Heart Center near the central point between the two breasts.. He should meditate only on the point in the Central Channel that is near the spine. Visualize a blue Hum word standing on a moon-wheel, head face down, the Bodhi-Heart like snow about to melt.

To locate the visualized word at the Throat Center, the yogi should visualize only the center-point of the sixteen nerve-leaves of the Throat Center in the Central Channel near the spinal column. Visualize at this point a red Om word, its head facing up, standing on the moon-wheel.

To locate the word at the Head Center, the yogi should visualize the word at the center of the nerve-leaves of the Head Center in the Central Channel near the spinal column. Visualize at the point a white Ham word, facing down, standing on the moon-wheel.

It is of great importance that the yogi should visualize the points in the center of the Central Channel, entwined by the knot of the Right and Left channels, at the cross sections of the four Chakras.

Says the Expounding Tantra Sambhoda:

"The lotus that reaches the inner part of the heart
Is the principal one, which has eight nerve-leaves.
The nerve that reaches the inside of it is like a lamp.
In shape, it resembles the plantain flower,
Leaves opened and facing downward.
The god who dwells within it
Is as small as the mustard seed.
The indestructible seed--the Hum,
Trembles like the snow about to melt..." [cf. the Upanisadic and the gotra teaching.]

The nerve that reaches the inner part of the heart is the principal nerve, which implies the Central Channel; the Hum world should be visualized in it. The other words in the other three Chakras should be visualized as well.

Although there are many different teachings on the word-visualization in the four Chakras, the essential point is to visualize these words in the center of the Central Channel. Nevertheless, this point is not clearly stated in some teachings. If it is not clearly understood, one will not be able to gather the pranas at the Central Channel; consequently one will miss the essence of the pith-instruction.

The size of the words on which the yogi meditates should be as small as the mustard seed--as the Tantra describes the Hum word. This size applies to the other four words as well.

The smaller and clearer the word as visualized and held by the mind, the easier it is to control the pranas. This is a very important factor in mastering the pranas.