I felt an immediate sense of faith and conviction in him as soon as I saw him face to face that night, both because of my conviction in the Dhamma he was so kind to teach me, and because of the assistance he gave in letting me stay under his guidance. I stayed with him with a sense of contentment hard to describe -- but also with a stupidity on my own part hard to describe as well. He himself was very kind, helping me with the Dhamma every time I went to see him.
My practice when I first went to stay with him was a matter of progress and regress within the heart. My heart hardly ever settled down firmly for a long period of time. The first rains I spent with him was my ninth rains, in as much as I had spent my first seven rains in study, and one rains in Nakhorn Ratchasima after starting to practice. During that first rains with Ven. Acariya Mun, there was nothing but progress and regress in the area of my concentration. After the rains, I went up to stay on a mountain for more than two months and then returned to be with him, my mind still progressing and regressing in the same way. I couldn't figure out why it kept regressing even though I was intent on practicing to the full extent of my ability. Some nights I was unable to sleep all night long out of fear that the mind would regress, and yet it would still manage to regress. And especially when the mind was beginning to settle down in stillness, I'd accelerate my efforts even more, out of fear that it would regress as it had before -- and even then it would regress on me. After a while it would progress again and then regress again. When it had progressed, it would stay at that level for only three days and then regress right before my eyes. This disturbed me and made me wonder: Why was it able to regress? Was it because I had let go of my meditation word? Perhaps my mindfulness (sati) had lapsed at that point. So I made a note of this and promised myself that no matter what, I would have to keep the meditation word in charge of my mind at all times. Regardless of where I would go, and regardless of whether I was in our out of concentration -- even when I was sweeping the monastery compound or doing any of my chores -- I wouldn't allow my mind to slip away from buddho, the word I liked to repeat in my meditation.
At this point, when the mind would settle down into stillness, if it could continue to think of the meditation word buddho in that stillness, I wouldn't let go of it. If the mind was going to regress in any way, this was where I would have to know.
As soon as I had taken note of this point and had made my promise, I started repeating the word buddho. As I was repeating it, the mind was able to settle down quickly, much more quickly than it had before. It would let go of its meditation word only when it had settled snugly into stillness. At that moment, whether or not I would think buddho, the awareness of that stillness was already solidly 'buddho' in and of itself. It wouldn't be forming any thoughts at all. At that point I'd stop my repetition. As soon as the mind made a move to withdraw -- in other words, as soon as it rippled slightly -- I'd immediately start pumping the meditation word back in again as a means of keeping the mind in place. At the same time, I'd keep watch to see at what point the mind would regress. I abandoned my concern for the progress or regress of the mind. No matter how far the mind might progress or regress, I wasn't willing to let go of my meditation word. Even if the mind was going to regress, I'd let it regress, because when I had been determined that it not regress, it had still regressed in spite of my determination.
Now, though, I felt no more concern for whether the mind would progress or regress. I'd simply force it to be conscious of buddho. I'd try to be aware of progress and regress only in terms of the heart that had buddho in charge. This was where I would know. This was where I would clearly see. This was the one spot in which I'd place my confidence. I wouldn't have to concern myself with progress or regress.
As time passed, the mind that had once progressed and regressed didn't regress. This was what made me realize: The fact that the mind had kept regressing so often was because of a lapse in its meditation word; mindfulness must have slipped away at that moment for sure. So from that point on I kept my meditation word continually in place. No matter where I'd go or where I'd stay, I wouldn't let mindfulness lapse. Even if I was to be on the verge of death, I wouldn't let mindfulness slip away from buddho. If the mind was going to regress, this was the only place where I'd try to know it. I wouldn't concern myself with the matter in any other way. As a result, the mind was able to establish a foundation for itself because of the meditation word buddho.
After that came my second Rains Retreat with Ven. Acariya Mun. Before the rains began, my mind felt still and firm in its concentration, with no regressing at all. Even then, I refused to let go of my meditation word. This kept up to the point where I was able to sit in meditation without changing to any other position from early night until dawn.
During my second rains with Ven. Acariya Mun, I held to sitting in meditation until dawn as more important than any other method in my practice. After that I gradually eased back, as I came to see the body as a tool that could wear out if I had no sense of moderation in using it. Still, I found that accelerating my efforts by means of sitting all night until dawn gave more energy to the heart than any other method.
The period in which I was sitting up all night until dawn was when I gained clear comprehension of the feelings of pain that arise from sitting in meditation for long periods of time, because the pain that arose at that time was strange and exceptional in many ways. The discernment that investigated so as to contend with the pain kept at its work without flagging, until it was able to understand the affairs of every sort of pain in the body -- which was a solid mass of pain. At the same time, discernment was able to penetrate in to know the feelings of the heart. This did a great deal to strengthen my mindfulness, my discernment, and my courage in the effort of the practice. At the same time, it made me courageous and confident with regard to the future, in that the pains that would appear at the approach of death would be no different from the pains I was experiencing and investigating in the present. There would be nothing about those pains that would be so different or exceptional as to have me deceived or confused at the time of death. This was a further realization. The pain, as soon as discernment had fully comprehended it, disappeared instantaneously, and the mind settled down into total stillness.
Now at a point like this, if you wanted to, you could say that the mind is empty, but it's empty in concentration. When it withdraws from that concentration, the emptiness disappears. From there, the mind resumes its investigations and continues with them until it gains expertise in its concentration. (Here I'll ask to condense things so as to fit them into the time we have left.) Once concentration is strong, discernment steps up its investigation of the various aspects of the body until it sees them all clearly and is able to remove its attachments concerning the body once and for all. At that point the mind begins to be empty, but it doesn't yet display a complete emptiness. There are still images appearing as pictures within it until it gains proficiency from its relentless training. The images within the heart then begin to fade day by day, until finally they are gone. No mental images appear either inside or outside the heart. This is also called an empty mind.
This kind of emptiness is the inherent emptiness of the mind that has reached its own level. It's not the emptiness of concentration, or of sitting and practicing concentration. When we sit in concentration, that's the emptiness of concentration. But when the mind has let go of the body because of the thorough comprehension that comes when its internal images are all gone, and because of the power of its mindfulness and discernment that are fully alert to these things, this is called the emptiness of the mind on its own level.
When this stage is reached, the mind is truly empty. Even though the body appears, there's simply a sense that the body is there. No image of the body appears in the mind at all. Emptiness of this sort is said to be empty on the level of the mind -- and it's constantly empty like this at all times. If this emptiness is nibbana, it's the nibbana of that particular meditator or of that stage of the mind, but it's not yet the nibbana of the Buddha. If someone were to take the emptiness of concentration for nibbana when the mind settles down in concentration, it would simply be the nibbana of that particular meditator's concentration. Why is it that these two sorts of emptiness aren't the emptiness of the Buddha's nibbana? Because the mind empty in concentration is unavoidably satisfied with and attached to its concentration. The mind empty in line with its own level as a mind is unavoidably absorbed in and attached to that sort of emptiness. It has to take that emptiness as its object or preoccupation until it can pass beyond it. Anyone who calls this emptiness nibbana can be said to be attached to the nibbana in this emptiness without realizing it. When this is the case, how can this sort of emptiness be nibbana?
If we don't want this level of nibbana, we have to spread out feelings (vedana), labels (sanna), thought-formations (sankhara), and cognizance (vinnana) for a thorough look until we see them clearly and in full detail -- because the emptiness we're referring to is the emptiness of feeling, in that a feeling of pleasure fills this emptiness. The mind's labels brand it as empty. Thought-formations take this emptiness as their preoccupation. Cognizance helps be aware of it within and isn't simply aware of things outside -- and so this emptiness is the emptiness of the mind's preoccupation.
If we investigate these things and this emptiness clearly as sankhara-dhammas, or fabrications, this will open the way by which we are sure some day of passing beyond them. When we investigate in this way, these four khandhas and this emptiness -- which obscure the truth -- will gradually unravel and reveal themselves bit by bit until they are fully apparent. The mind is then sure to find a way to shake itself free. Even the underlying basis for sankhara-dhammas that's full of these fabricated things will not be able to withstand mindfulness and discernment, because it is interrelated with these things. Mindfulness and discernment of a radical sort will slash their way in -- just like a fire that burns without stopping when it meets with fuel -- until they have dug up the root of these fabricated things. Only then will they stop their advance.
On this level, what are the adversaries to the nibbana of the Buddha? The things to which the mind is attached: the sense that, 'My heart is empty,' 'My heart is at ease,' 'My heart is clean and clear.' Even though we may see the heart as empty, it's paired with an un-emptiness. The heart may seem to be at ease, but it depends on stress. The heart may seem clean and clear, but it dwells with defilement -- without our being aware of it. Thus emptiness, ease, and clarity are the qualities that obscure the heart because they are the signs of becoming and birth. Whoever wants to cut off becoming and birth should thus investigate so as to be wise to these things and to let them go. Don't be possessive of them, or they will turn into a fire to burn you. If your discernment digs down into these three lords of becoming as they appear, you will come to the central hub of becoming and birth, and it will be scattered from the heart the moment discernment reaches the foundation on which it is based.
When these things are ended through the power of discernment, that too is a form of emptiness. No signs of any conventional reality (sammati) will appear in this emptiness at all. This is an emptiness different from the forms of emptiness we have passed through. Whether this emptiness can be called the emptiness of the Buddha, or whose emptiness it is, I'm afraid I can't say, other than that it's an emptiness that each meditator can know directly only for him or herself alone.
This emptiness has no time or season. It's akaliko-- timeless -- throughout time. The emptiness of concentration can change, in terms of progress and regress. The emptiness on the formless or image-less (arupa) level, which serves as our path, can change or be transcended. But this emptiness exclusively within oneself doesn't change -- because there is no self within this emptiness, and no sense that this emptiness is oneself. There is simply the knowledge and vision of things as they are (yatha-bhuta-nana-dassana) -- seeing this emptiness in line with its natural principles as they actually are, and seeing all phenomena as they actually are, as they pass by and exist in general. Even virtue, concentration, and discernment -- the qualities we use to straighten out the heart -- are realized for what they are and let go in line with their actuality. Nothing at all remains lurking in the nature of this final stage of emptiness.
I ask that we all reflect on these three kinds of emptiness and try to develop ourselves to attain them -- and especially the last form of emptiness, which is an emptiness in the principles of nature, beyond the range where any other person or any conventional reality can become involved with us ever again. Our doubts, ranging from the beginning levels of the Dhamma to this ultimate emptiness, will find resolution, with our own knowledge and vision acting as judge.
So now at the end of this talk -- which started out with my telling you of my own ignorance step by step and then strayed off to this final emptiness, which is a quality somewhat beyond my powers to explain any further -- I'll ask to stop, as the proper time seems to have come.
May happiness and contentment be with each and every one of you.

An excerpt from a talk given July 6, 1982
. . . Whichever theme you focus on, be earnest with it, keeping mindfulness in constant touch with the work you are doing. For example, if you're focusing on the repetition of buddho, keep constantly aware of the word buddho, buddho, as if there were nothing else left in the world for you to become two with this or three with that. There is only one thing: the word buddho blending step by step with your awareness. As the mind becomes more and more still, the buddho you are repeating will more and more blend into one with your awareness. Then the word buddho, buddho will fall silent, leaving only an awareness that's more conspicuous than before. This means that you've reached the mind. To put it in terms of following the tracks of an ox, you've reached the ox and can let go of its tracks. Here you've reached the inner buddha, which is like the ox, so now you can let go of the meditation word.
The same holds true if you focus on keeping the breath in mind. Whether the breath is heavy or refined, simply be aware of it as it normally is. Don't set up any expectations. Don't force the breath to be like this or that. Keep your awareness with the breath, because in meditating by taking the breath as your preoccupation, you're not after the breath. The breath is simply something for the mind to hold to so that you can reach the real thing, just as when you follow the tracks of an ox: You're not after the tracks of the ox. You follow its tracks because you want to reach the ox. Here you're keeping track of the breath so as to reach the real thing: awareness. If you were to start out just by holding on to awareness, you wouldn't get any results, just as you wouldn't be sure of finding the ox if you simply went around looking for it. But if you follow its tracks, you're going to find it for sure. Your meditation word has to keep moving in. This is called following the tracks of the ox step by step until you reach the ox, or what knows: namely the mind.
The same holds true with focusing on the breath. If it's heavy, know that it's heavy. Don't get worried or upset about it, and don't be afraid that you'll die because the breath is heavy or because you feel suffocated. When you do heavy work, you feel suffocated -- don't think that you feel suffocated only when focusing on the breath. There are a lot of other things more suffocating than this. If you carry a post or lift something heavy, you feel suffocated to death all over the body, not just in the chest or in the breath. The whole body is ready to burst because of the heaviness and great pain, and yet you can take it. You even know that it's because of the heavy object, and that's the way it has to be.
While you focus on keeping the breath in mind when the breath is coarse, it's as if you were lifting something heavy. It's naturally bound to feel suffocating, so don't worry about it. Even if it's suffocating, the important point is to keep track of the breath coming in and out. Eventually the breath will become more and more refined, because mindfulness is focused on the breath and doesn't go anywhere else. When the breath goes in, be aware of it. When it goes out, be aware of it, but there's no need to follow it in and out. That would simply be creating a greater burden for yourself, and your attention might slip away. So focus right on the entry point where the breath goes in and out. In most cases, the tip of the nose is the place to focus on the breath. Keep watch right there. Keep aware right there. Don't waste your time speculating or planning on how the results will appear, or else your mind will wander away from the principle of the cause that will give rise to those results. Keep close watch on the cause -- what you are doing -- and the breath will become more and more refined.
When the breath becomes more refined, that shows that the mind is refined. Even if the breath becomes so refined that it disappears -- at the same time that you're aware that it's disappearing -- don't be afraid. The breath disappears, but your awareness doesn't disappear. You're meditating not for the sake of the breath, but for the sake of awareness, so stay with that awareness. You don't have to worry or be afraid that you'll faint or die. As long as the mind is still in charge of the body, then even if the breath disappears, you won't die. The mind will dwell with freedom, with no agitation, no worries, no fears at all. This is how you focus on the breath.