Inside the vacuole at the heart, there is another moon cushion, upon which is a letter HUM, which is the nature of the indestructible drop. It is the size of a mustard seed and blue in colour. Both the letter and the moon cushion are suspended upside down. The indestructible drop is the most subtle drop, and is so called because it does not melt before the time of death.
Finally, in the vacuole of the navel we clearly visualize another moon cushion. Upon this, again the size of a mustard seed, is a red letter short-AH standing upright, which is the nature of the red drop residing in the navel. As this is the principal object of concentration when meditating on the yoga of inner fire, and as all the body’s warmth is generated from this drop, the short-AH should be visualized in the nature of fiery heat. A diagram depicting how these four letters should be visualized is given in Appendix III.
There are two specific purposes of visualizing these letters in the vacuoles of the central channel at the centre of each channel wheel. The first purpose concerns the four joys. We can experience these four joys only when the winds enter, abide, and dissolve within our central channel. The longer and more intensely we can hold the experience of the four joys, the better our experience will be; and our ability to do this is greatly enhanced by visualizing the four letters. As a result of the meditation described below, the white drop in the crown is made to melt. When it does so, it begins to flow down the central channel, eventually passing through the throat, heart, and navel channel wheels, and finally reaching the tip of the sex organ. Once the white drop melts, it descends without interruption. If it flows through a particular channel wheel without being checked or held there, the experience of joy associated with that channel wheel will be fleeting and unstable. However, by focusing our concentration on the various letters, we can arrest the downward flow of the white drop and thereby gain a longer and more intense experience of each of the four joys.
The four joys are explained fully in the next chapter, but a brief description will be useful at this point. The first joy is called simply ‘joy’, and the experience of it originates in the crown channel wheel when the white drop residing there melts. Therefore, initially we must meditate for a long time on the letter HAM in the crown. The experience of this joy is complete when the white drop flowing down the central channel reaches the throat channel wheel.
The second joy, called ‘supreme joy’, originates in the throat channel wheel, and is experienced in full when the white drop flowing down the central channel reaches the heart channel wheel. The third joy, called ‘extraordinary joy’, originates in the heart channel wheel, and is experienced in full when the white drop flowing down the central channel reaches the navel channel wheel. Finally, the fourth joy, called ‘spontaneous great joy’, originates in the navel channel wheel, and is experienced in full when the white drop flowing down the central channel reaches the tip of the sex organ. Thus, to have a sustained and stable experience of each of these joys, we must have gained strong control over the downward-flowing white drop and be able to arrest it at each level of its descent, and this is accomplished by gaining familiarity with the four letters in meditation.
The second purpose of visualizing the letters in the channel wheels is to help us to find the actual object of meditation in the yoga of inner fire. The letter HAM is visualized within the vacuole of the crown channel wheel. Although its outer appearance is that of a letter, we should recognize it as actually being the white drop in the crown. When we practise the fourth stage of inner fire, we should begin by visualizing this white HAM in the crown. We visualize it clearly for a short time and then we move our attention to the red OM in the throat. After a while, we move to the HUM in the heart, and finally we settle the mind on the short-AH in the navel channel wheel. We visualize the short-AH very clearly and feel that it is the nature of powerful, fiery heat. Our concentration should be focused on this letter for a longer time than on the others.
After concentrating on the short-AH, we move our mind back to the HUM at the heart, then on to the red OM in the throat, and finally to the white HAM in the crown. Then we move down again, back to the throat, the heart, and finally stop at the navel. In this way, we move our mind from the crown downwards, from the navel upwards, and finally from the crown downwards once again.
At this point, our concentration is focused on the short-AH of inner fire in the centre of the navel channel wheel. If it is not perceived clearly, our meditation will not be successful. Therefore, this is the time to recall as vividly as possible the pointing-out instructions that we have received from our Spiritual Guide concerning the specific characteristics of the short-AH, such as its location, size, shape, and nature. We visualize the sixty-four spokes of this wheel and the coiling right and left channels that form a twofold knot at the hub of these spokes. Inside the central channel at the centre of this knot is the vacuole of the navel. It is within this vacuole that the letter short-AH resides, standing on a tiny moon cushion. The letter is red in colour, completely pure, infinitely radiant, and has the nature of intense fiery heat. This is the object of inner fire meditation.
Finding the object of meditation depends upon mindfulness and alertness. After finding the object in the manner described above, we should completely dissolve our mind into it and concentrate on it single-pointedly without forgetting it. If this proves difficult, we can think that the letter is our body and that our mind is dwelling within it; or we can think that it is like clothes that we, the mind, are wearing. These techniques will help to close the gap between the subjective mind and the object of meditation. Once we have found the object of meditation, we have reached the first stage of tranquil abiding meditation, if we have not already reached this stage through previous practice. If we meditate continuously, we can gradually accomplish all nine mental abidings. Thus, the short-AH is a unique object of meditation because a single meditation on it yields four important fruits: attaining tranquil abiding; causing the winds to enter, abide, and dissolve within the central channel; igniting the inner fire and causing it to blaze; and accomplishing the realization of Mahamudra.
The present meditation is done primarily to bring the winds into the central channel, and success in this depends upon perfect concentration. Therefore, whenever we do this meditation it is important that we do not see our mind and the object of meditation as being different. As mentioned before, we should completely dissolve our mind into the short-AH so as to eliminate the gap between subject and object. When we are able to do this, we will be able to gain control over the winds so that they enter, abide, and dissolve within the central channel. This is the basis for all the subsequent stages of meditation that culminate in the realization of the Mahamudra.
Khedrub Sangye Yeshe
IGNITING THE INNER FIRE (TUMMO)
The concentration that was generated in the fourth stage of meditation is focused on the letter short-AH within the vacuole of the navel channel wheel. We now combine this concentration on the short-AH with holding the vase breath.
We begin the vase breathing by drawing a portion of the winds of the lower body upwards and gathering them just below the short-AH at the navel channel wheel. This is accomplished by relying mainly upon the power of imagination; we merely feel that we are constricting the muscles of the lower part of our body and thereby drawing the winds gently upwards. As a result, the muscles controlling the retention of urine, excrement, and so forth will constrict slightly, but not to the extent that the two lower doors actually close. We then inhale through both nostrils gently, slowly, and deeply, and visualize that all the winds of the upper body flow down through the right and left channels. When they reach the navel, they enter the central channel and gather just above the short-AH. The third stage of the vase breathing is actually to constrict the muscles of the pelvic floor so that the two lower doors close, and then to draw up completely all the winds of the lower part of the body. These winds then unite with the winds already gathered just below the short-AH. Then we gently swallow some saliva without making any noise. This presses the upper and lower winds together slightly.
We now think