When investigating Chan, first of all you should have no mark of self. Why do we investigate the topic "Who is mindful of the Buddha?" To get rid of the self. If you really work hard and really make progress, then you won't have any other false thoughts. You won't feel pain in your legs. Since you forget both pain in the legs and false thoughts, then you only single-mindedly ponder the topic of "Who is mindful of the Buddha?" Such continuous deep concentration can change time and can chase away states. Why do I say it can shorten time? When you begin to get a response from applying effort in investigating "who?" then you will have no more than sat down when you will hear the bell ring to end the sit. You will not be aware that one hour or half an hour or two hours have passed. The end of the sitting period will come faster than the blink of an eye. Isn't that a case of time being shortened and changed? Simply by investigating the topic "Who is mindful of the Buddha?" you can cause your awareness of leg pain and back pain to vanish. It vanishes because you don't have your mind on it. Since you don't have that attachment in your mind, when you sit there, you won't feel uncomfortable. Your legs won't hurt. Even if they do hurt, you won't be aware of the pain. And so you don't want to say, "Why aren't I attaining any tangible result?" Just because of that second thought-wanting some tangible results-you have already lost your skill.
Who truly know how to work do not lose track of the topic "who?" Little by little they inquire into "who" until mind, intellect, and consciousness all vanish. The mind becomes empty; the body is also empty; the intellect is empty, and the consciousness is empty. When you strike up false thoughts, it is the sixth consciousness that they come from. The sixth consciousness causes you to strike up false thought, causes you to register pain, and causes you to be unable to bear any more. All of those are distortions of the sixth consciousness. If you are able to smash the mind, intellect and consciousness--if you investigate until you break through them, so that you can't be turned by such thoughts--then you are one who truly knows how to work. Not to mention gaining responses every day in your application of effort, if you gain a response for even the space of a thought, you can open your wisdom, which is another way of saying you can become enlightened.
An ancient saying goes,
If someone sits quietly for an instant,
That is better than building pagodas made of the seven jewels in number
like the Ganges' sands.
"If someone sits quietly for an instant"--even for such a brief period of time; if you can truly become quiet, "then that is better than building pagodas made of the seven jewels in number like the Ganges' sands." If you can genuinely enter samadhi--stay quiet--for an instant, for just a moment in time, then that in itself can eradicate infinite kalpas of offenses that bind us to birth and death. That is why we need to investigate Chan. As long as you can sit quietly, the merit and virtue will be much better than that of building pagodas of the seven jewels numbering like Ganges' sands.
When you build Ganges' sands' pagodas of the seven jewels, you are merely making material offerings to the Buddhas, which may serve to influence people to bring forth their own resolve. If you can sit quietly in an instant, you are creating a true Buddha, which is to say, a living Buddha. Returning to the self-nature and gaining the original light of wisdom is genuine merit and virtue. Building external pagodas of the seven jewels like sands in the Ganges is a conditioned dharma. What you are doing is an unconditioned Dharma. Sitting quietly is cultivating an unconditioned Dharma. That's why it's said, "If someone sits quietly for an instant, that is better than building pagodas made of the seven jewels in number like the Ganges' sands." Well, since just one instant's merit and virtue is that great, how much the more is that derived from sitting pure and still, astute and clear, without dozing off or falling asleep for an entire hour, and yet feeling that the time has passed swiftly.
Someone who is really working hard at developing his skill will not even know how many days have passed in a Chan session, because there is no need for him to pay attention to the time. When I meditated for ten weeks on Kongqing (Empty Blue) Mountain, I had no idea ten weeks could pass so fast. Since there were people to take care of counting the days, I didn't need to keep track of it myself, and so I felt the time passed very fast. My legs didn't hurt either. I sat for one hour, two hours, and even the entire day, and they never hurt because I'd broken through the pain barrier. After you have sat for a long time, the pain will subside and settle down.
You are not alone in experiencing pain. Anyone who has just begun to meditate will experience all kinds of discomfort, such as pain in the legs and aches in the back; they will feel uncomfortable all over. At that time, if you can summon your patience and concentrate your mind, you will have the kind of samadhi-power needed to defeat all difficulties. You will be able to break through all barriers. Once you break through those barriers, another vista opens up.
What states have you had? Did your state come from your imagination or was it real? If it's merely false thinking about wanting to see a certain state, then it's phony. If you weren't having false thinking, if basically you weren't thinking at all, then it's true. If you have the thought beforehand, "Oh! I want to see lotus flowers" and then a flower shows up, then that's phony. Or you think, "Ah! I want to see a Buddha" and, wow! A Buddha appears. That's also phony. If you first want to see anything and then you see it, that is phony. But if you had no thought of wanting to see and you saw, then that's true. If you haven't had a prior false thought--before such a thought ever comes up--then if you see some state you didn't think of beforehand, then in most cases the state will be true. Of course sometimes even then it's just an illusion. What is most important is that no thought of it has come up beforehand. Then, if you have some state, there may be something to it.
However, in investigating Chan, one shouldn't want states to arise. We don't want there to be anything, only emptiness--not even emptiness. It means having even emptiness be empty, and yet being without fear and without joy. If you experience a kind of fear, then you will be open to attacks by demons. If you experience a kind of happiness, then a demon of happiness will come. Look at the Fifty Skandha-demons discussed in the Shurangama Sutra. All of those states could be encountered when meditating. If you are clear about those states, you will not be turned by any state that you may see. There is a saying, "If the Buddha comes, smash him. If a demon comes, beat him away." If a Buddha comes, don't become attached to that Buddha. If a demon comes, don't become attracted to that demon. Do not have any attachments. Don't think: "Wow! A Buddha has come!" and be overjoyed about it, because then you will not act properly. If you are under the influence of passion, fear, or fond regard, you will also be incorrect in your conduct. Therefore, you must be able to remain "thus thus unmoving" in stillness; you must remain unmoved no matter what state you encounter so that you do not give rise to discriminations about it and you do not pursue it.
If a state appears, let it be. If no state appears, don't look for any. If you perceive a state, don't be turned by it. From limitless kalpas past until the present, we have accumulated all kinds of states of mind within the field of our eighth consciousness. Sitting quietly allows these states to come forth. By analogy, if you keep stirring muddy water, it will not be clear. But if you put the water some place and don't disturb it, then all the mud and sediment will sink to the bottom and the water will become clear. It's the same with you. Once you sit quietly, your mind will become clear.
"The mind's clarity is like that of water in which the moon can reflect." Your mind's clarity will be like the clarity of water that allows the moon to reflect in it. "The intellect in samadhi is like a cloudless sky." If the mind is in samadhi, if you can enter samadhi, then that's like a clear day without any clouds. And so pay no attention to whether a state of mind is true or false. Working hard is true. On the other hand, you also shouldn't go to the other extreme when a state comes up. Many people don't understand what's happening, and so they say, "Ah! This is not good. You are possessed by a demon." In fact it is because you've worked hard that you encounter such a state. If you hadn't worked hard, nothing at all would have happened. And so do not be afraid. True understanding is not being attached to anything. Don't be attached to anything at all.