letter short-AH is completely enclosed by the upper and lower winds, like a jewel in an amulet box. The size of this visualization should be that of a small pea that has been cut in half, hollowed out, and rejoined around an even smaller mustard seed.
We fix our attention single-pointedly on the letter short-AH enclosed within the small sphere, and stop all inhalation and exhalation. Once we are concentrated in this way, it is no longer necessary to keep the lower doors closed. We remain concentrated like this without breathing until we are about to feel discomfort. Then, just before exhaling, we visualize the upper and lower hemispheres of wind dissolving into the short-AH, which, as a result, grows even hotter than before.
We exhale slowly and gently through the nostrils (not through the mouth), all the while remaining concentrated on the short-AH in the centre of the navel channel wheel. We relax for a while, and then continue the vase breathing as before. We can take seven, twenty-one, or more consecutive vase breaths in one meditation session, depending upon the time we have available. If possible, we should not take any additional breaths between the exhalation marking the end of one vase breath and the inhalation marking the beginning of the next. However, if this proves too difficult we may take a few intermediate breaths.
There are other ways of doing vase breathing, but they are in essence the same as the method explained here. This particular method is most suitable for the present practice. While doing this meditation, we do not let our concentration stray from its object, even momentarily, and we always keep in mind that the short-AH is the nature of fiery heat. We need to repeat this practice of holding the vase breath as many times as we can so as to become completely familiar with it.
Once again it is important to stress the need for our concentration to be accurately focused on the proper place within the central channel. The vacuole within the central channel is in the centre of the navel channel wheel, and it is here that the short-AH is visualized and the winds gather. We need to perform four important tasks during this stage of the meditation: (1) constantly to check to see if the place of meditation is accurate, (2) to find the object of meditation without difficulty, (3) to hold the object of meditation continuously through the force of mindfulness, and (4) to have our mind mix completely with the object of meditation. If we practise these four well, we will definitely succeed in our meditation on inner fire, and as a result we will be able to cause the winds to enter, abide, and dissolve within our central channel.
There are two purposes served by holding the vase breath. The first is that we arrest the flow of wind within the right and left channels and thereby pacify the gross conceptual minds. As mentioned before, if the winds stop flowing within the right and left channels they must then flow within the central channel.
Concerning this first purpose, it should be noted that it is possible to bring the winds into the central channel merely by concentrating on the short-AH, without doing vase breathing at all. This is the most peaceful of all techniques for bringing the winds into the central channel and it is excellent if we are able to do it. With this method, there is no danger of disturbing the winds. Moreover, this method is more powerful than others for gaining a realization of clear light. On the other hand, by using the vase breathing method we are able to bring the winds into the central channel much more quickly.
As indicated before, the vase breathing technique itself can be performed either peacefully or forcefully. The technique described here, wherein the muscles of the lower body doors are constricted gently, is the recommended peaceful method. The more forceful method involves clenching the muscles of the arms and legs, thereby forcing the lower winds to gather more rapidly. It is said that if a meditator does not experience success with the peaceful method, he or she should practise a more forceful method for a while and then return to the gentler technique.
There is a similarity between the different methods for causing the winds to enter the central channel and the different ways of dying. The peaceful method, whereby we merely concentrate on the short-AH, is similar to the process that occurs during a natural death, when the winds dissolve into the central channel slowly and progressively and therefore allow a greater opportunity for discerning and meditating on clear light. The most forceful method is similar to what happens during a sudden, violent death. The winds dissolve very quickly, and as a result of this hurried movement it is more difficult to be aware of the appearance of clear light. Therefore, the best way to meditate would be to use the vase breathing technique at first to gain experience in concentrating the mind on the short-AH in the navel channel wheel, and then, once familiarity has been established, to proceed with the more peaceful method of using concentration alone.
The second purpose served by holding the vase breath has to do with the downward-voiding wind residing in the central channel just below the navel channel wheel. By dissolving the upper and lower winds of the body into the short-AH as described above, we are able to cause the downward-voiding wind to move upwards. When this happens, the inner fire will ignite and blaze.
When people engage in sexual intercourse, the downward-voiding wind is also caused to move upwards by the union of the male and female sex organs, but this movement does not take place within the central channel and so the result is only a momentary igniting and blazing of the ordinary inner fire. Because of this ignition and blazing, the drops in the lower part of the body melt and flow downwards, resulting in a brief experience of bliss, but this lasts only until the drops leave through the sex organ or, in the case of the woman, collect in the uterus. By holding the vase breath and concentrating on the inner fire, however, the downward-voiding wind can be caused to move upwards inside the central channel. This will cause the inner fire to ignite and blaze and the drops to melt – all within the central channel. Those who do not practise Secret Mantra cannot accomplish this result. Although they may be able to ignite the ordinary inner fire and cause it to blaze through sexual intercourse, they are unable to cause the drops to melt within the central channel or to cause them to descend from the crown channel wheel. Since ordinary sexual intercourse cannot cause the winds to enter the central channel, or cause the inner fire to ignite and blaze therein, it can never benefit the practice of completion stage.
Just as ordinary sexual intercourse can cause the inner fire to ignite and blaze in the fashion described, so too can certain ordinary meditations generate the heat of inner fire within the body. However, generating such heat serves no purpose other than to keep the body warm; it lacks the power to bring realizations. If our only aim is to warm the body, we do not need to do meditation; it would be easier simply to wrap ourself in a blanket or to put a heater on!
To practise inner fire purely, we should strive to ignite the inner fire within the central channel, for to ignite it outside the central channel will only detract from the heat that could be generated within. As a result, the drops will not melt and flow within the central channel, and the meditation will not bring any completion stage realizations. If Mahamudra meditation is not successful, it will not be possible to perceive the clear light. On the other hand, when the inner fire ignites and blazes within the central channel, the winds enter, abide, and dissolve therein. Then there is nothing to prevent us from generating spontaneous great bliss, the main purpose of inner fire meditation.
To ignite the inner fire by means of the vase breath, we visualize that as a result of dissolving the upper and lower winds, the downward-voiding wind flows upwards and blows against the short-AH. It should be noted that whereas before the lower winds of the body were merely visualized as ascending through the central channel to form the lower half of the sphere surrounding the short-AH, now the downward-voiding wind below the navel channel wheel actually does flow upwards to blow against the letter. Just as red coals grow hotter when blown upon by bellows, so the short-AH now burns more intensely as it is fanned by the downward-voiding wind. We imagine that the letter becomes so hot that it could consume anything. We visualize that it becomes hotter and hotter, all the time glowing more brightly, until the fine upper tip of the nada of the short-AH finally bursts into flame for a moment and then dies down again. The nada continues to flare up and subside in this way as it is fanned by the upward movement of the downward-voiding wind, just as hot coals flare up and subside as they are blown on by bellows. This is the fifth stage of the meditation, which is called ‘igniting the inner fire’. We should continue training in this practice until we have actual experience of this ignition.
According to Je Tsongkhapa’s