It is also called the four abodes of mindfulness. 

The first is the observation that the body is not pure.
The second is the observation that feeling is suffering.
The third is the observation that mind is without constancy.
The fourth is the observation that Dharm is without self. 
     
     To say that "the observation that the body is not pure,” is that one skin bag observed as a body now is the whole universe in ten directions. Because this is the true body, it is the observation that the body is not pure, springing up on the road of liveliness. But for springing up, it would be impossible to observe, it would be without body. It would be impossible to practice, it would be impossible to preach, it would be impossible to observe. But the manifestation of observed attainment is already present, remember, it is the realization of vivid springing up. The so-called observed realization is everyday activity of living, sweeping the ground and sweeping the floor. Because we sweep the ground, upon what number moon it is, and sweep the ground and sweep the floor upon what precisely second moon this is, it is suchness of the whole earth.

And the first is the big item as “The Four Abodes of Mindfulness.” It says the four mindfulness, so there are four. The four come out there. To observe that body is not pure. To observe that feeling is suffering. To observe that mind is without constancy. To observe Dharma is without self. The four are expressed like this. “Without constancy” or “without self” comes out in what is said three dharma seals, like myriad dharmas are without self or myriad things are without constancy. Being so they are words that always appear in the basic teaching of Buddhism. 
     “The observation that the body is not pure.”
is that observing the body now, when you see the body, whole is covered with skin, all over. Inside it, there are flesh, bones, vessels, entrails. What is completed with various things is the body of human beings. It is also called the stinking skin body. Inside this one, full of ill smelling things are contained. That is the body of human beings, it is expressed like that. 
     Well,
“one skin bag is the whole universe in ten directions.” Don’t you think, what? You cannot easily think that this (this body) is all. There are so many various things in this room, who is doing such? Does the other person do it? This body called a skin bag has been always sensing like this. Opening the window, we can see the direction of the vast sea. I heard the story of the rising sun on the New Years’ Day. Beyond the sea, everything including the night sky spreads to the end of the earth, the whole universe in ten direction, though, the whole is the state of yourself. There is nothing as the state of others. Saying every conceivable kind of sounds, you are enjoying, though, you cannot absolutely hear the sound without this (pointing his body and mind). Depending on this (pointing his body and mind), the sound comes out, we can say that. 

     To that extent, this skin bag is the whole universe in ten direction. However, in general, we haven’t learned like that. This (pointing his body) is only this much,  just this separated, we are taught that only this is the self and the rest is out of yourself. We cannot know what is happening, if we don’t see with our own eyes. We cannot know how it is, if You don’t hear with your own ears. We know nothing at all, if we don’t depend on this (the body and mind). We understand all depending on this. That is why we learn what we ourselves are, being said Kojikyumei; to know oneself. We can know everything if we study only this one. 
     “Because this is the true body,” your body and mind isn’t like that, is it? What I am saying is unbelievable? Is there anyone who has a doubt? Anyone who is against it? That can’t be. “it is the observation that the body is not pure, springing up on the road of liveliness.” It is the active lively state, the road of liveliness is. What is called life is written being lively and being active. How great it is. 
     “But for springing up, it would be impossible to observe,” If it were not for springing up, it would be impossible to see. Its meaning is if you are concerned with the previous matter forever, you cannot observe the state of now clearly. Clap! Clap!(clapped his both hands) When I make sound like this, Clap! If you call the previous sound into question, you cannot hear the sound.  Clap !If you want really to hear a sound, you should observe the state where the sound of now is just sounding like this. Clap! Clap! That sort of thing is said "but for springing," it is said that you must spring up. While you are likely to deal with the previous issue, you cannot touch the real sound. 
     It is the same with things. When you see this side like this, if you take up what you saw before, you cannot see this correctly. The same can be said of everyday affairs in the living. You may possibly live such, you live on the state that you cannot see the truth. That is why you take up things of the past and grumble in disregard of that the vivid lively living is unfolding now. 
     It would be without body, “it would be without body.” “It would be impossible to practice, it would be impossible to preach,” You cannot obtain and preach. You cannot practice and you cannot observe. What's more, after seeing such a thing, there remains no sign of “I". It is wondrous that various things are taken up. But you don’t have to worry, “But the manifestation of observed attainment is already present,” is the way to be relieved for you. It says that everybody has already accomplished. It has been done, because the manifestation is present. It has already been accomplished as such now. 
     “remember it is the realization of vivid springing up.” There is none who are doing what happened before. Holding a pencil like this, there is none who is doing the previous event when writing. What do you think? When writing this, you cannot do the previous matter. There only exists the state you are writing now. That much you are separated from all things. Master Dogen sees through such a fine thing like this. 
     “The so-called observed realization is everyday activity of living, sweeping the ground and sweeping the floor.”
So called observation is everyday living, acting, the life. Tomorrow you are going to do cleaning, though, it is that you sweep the front, sweep the ground, and dusting the alcove. It is the everyday occurrence. It says that things of that kind have already been acted practically. When sweeping ground, you are not doing the previous event. You always do what you are doing now like this. But human beings, even though it is like that, are concerned with what they did before rather than what you are doing now. Therefore, it doesn’t become clean when cleaning finished. They saw, they must have seen, though, but they didn’t see. They seem to have touched, but they have not touched the thing of now. All the time their mind has gone somewhere. You should be careful. On this point, it can be said. 
     “Because we sweep the ground, upon what number moon it is, and sweep the ground and sweep the floor upon what precisely the second moon this is, it is suchness of the whole earth.” In this part, it is only said that we don’t do what was in the past. You should really look carefully. What you are doing now just exists as it is. The content is the supreme state which you seek for. There is no dust to brush. It is not such cleaning like you wipe as it is dirty, or you sweep as it is dirty. It is the Buddhist priest’s work, the work which is done in a temple. General cleaning is the degree that you make it clean because it is dirty or unclean. The Buddhist work in a temple is not so. When doing like this, the body and mind become purified depending on it. There is entirely no previous thing left. It is good you make it clean to that extent.