The poem I recited from recently at the mini retreat, from The Unfettered Mind by Takuan Soho:
Although it does not mindfully keep guard
In the small mountain fields
The scarecrow does not stand in vain.
In my twenties I lived in a Rinzai Zen Monastery with a Roshi in Japan.  We were all attracted to the teacher and his huge state of mind.  It was clear that he was functioning in a way different than everyone around him.  When someone asked him a question, it seemed to spring out of some empty place.  And there was this immense energy around him.  It was as if he was functioning without the filter of the intellect.  A kind of walking everyday samadhi.  And he told us from day one that the answer is not about being mental. He told us ten thousand times in sanzen that it is not in the head. Not to reach out to it or grasp with the intellect. 
So we had this example of someone who was functioning in this incredible way, but no sense of how to get there. We saw that the highest level of functioning was from this place of no mind, or Mu Shin.  
Most of us feel like it is impossible to function in that way. Many of us hear or read that we must let go in our practice. But we worry that if we let go of our calculating mind, our smart manipulating mind, we’ll be helpless or depleted. We’ll be fragile or let everyone down.  We’ll be a fool, banging into things as we walk and constantly saying the wrong thing. We think that letting go is the most frightening thing, because we are controlling our environment to feel safe and worthy and acknowledged. 
In all of the intensity of effort and earnest monastic practice, at a certain point it was clear that I needed to get into my body as the foremost task.  Like many of the newer monks, I was like a walking ki problem.  I was not in my body. My body was this thing “over there” that I dealt with. It bothered me most of the time.  It felt confused and jagged. My mind felt trapped in a stream of thoughts which I felt as tension in my body. Like a pressure cooker with no release valve. 
I had some very good tools to work with my body.  I of course had the tanden training. I learned Zhan Zhuang from another monk in the monastery. This was extremely helpful to get my zazen going. I’ve written about it before here.
Everything I am writing about below was in the context of a very structured training environment. 
Early in my practice, I found myself a bit strangled by the intense form of Zen training. I was struggling to do the practice right and to get it. In some ways the rigid Zen form was wonderful, and in other ways it took me further into that good and bad head, further into calculating. I had a lot of pain in zazen.  I saw people sitting very well. I saw them functioning well in the monastery, flowing, never messing up. And I was just floundering. Full of energy but just bouncing through conflict after conflict. I needed some practice space (both physical and time) to see what happened when I shed all ideas of good and bad.  Some time when no one was watching me in the zendo, walking by with the keisaku ready to hit me if the ki took my body into sawing here and there.
I took the time every day, maybe an hour, to feel into my body.  And in this process, what I am trying to communicate through this blog post, I found that feeling into the body is a gateway to this Mu Shin.
Before my training, I had already found a practice of physically and mentally letting go called non-directed body movement. But honestly it is not so much the name of the practice that matters but that I had to take away all techniques and see what was left. What was still there when I let go of my ideas of how it should be? Was something still holding my body up in gravity when I totally relaxed?  If I finally felt the tension in my back, would I explode?  Cry my eyes out?… What was this body, who is it in this body, and how could I truly meet it?
In combination with the structure and form of monastic practice, I began to see the gifts that emerge when I took the time to physically and mentally let go of control.  That’s what I’d like to talk about. What developed in the laboratory of that exploration that occurred when I met reality and creatively let go of control.
Learning to do zazen and beginning to connect with our own process is extremely creative.  We all have to find our own way.  It is profoundly personal how all of this works. In a zendo of fifty people, there are fifty different ways in to connect with this process.  So finding our own way is the practice. Finding our way to connect with the sweet spot of each moment, connected with reality, or be centered.
Over time, in my unique fascination, I found a way to explore what it is to let go of the calculating mind. I found that, in fact, the very act of allowing the body to open up naturally, spontaneously brought me to the place of unified non-thinking. In a physical, sensory way, practice guided me how to align with this great life energy. 
In the zendo or in the garden standing, in order to get out of the way and allow the body to open up, I had to let go of any idea of what was happening.  My control or understanding prevented me, like a constriction, from being open to this process. The internal language involved in melding with what is happening in the energy of the body requires one to let go of this calculating.  And this act of melding with what is happening is transformative.
“Our bodies already know how to birth true wisdom.” Shodo Harada Roshi
So what does that look like? In between work and zazen in the zendo, I’d go to the garden and just stand there. And I would stop. I would not try to do zazen. I would not try a technique. I would take away anything extra in my perception and just honestly feel what was happening.  I saw that really any control I was putting into the process was an impediment. And then when I got quiet enough, some inexplicable place would begin to turn or move within my system.  A long occult place in my consciousness would begin to unwind or thaw, and the energy field of my body would seal, come alive in a unified way I had previously not felt. That was shocking and counterintuitive. It was like my thinking had nowhere to land. I began to see what true harmony is. It felt right and good. As my body unified, I saw that harmony with all things was possible. My ideas of good and bad dissolved as I saw unity was naturally occurring if I let go into this natural unfolding.  
I began to experience every day that I had to let go of that mind that wanted to figure it out in order for this harmony to ensue. In order for my body to open up, I had to have no idea of how it would happen. I needed to let go of my calculating mind to allow my body to begin to open up.  The ki would not flow unless I let go of the mind. So it was a physical process. Over time this molded me from someone who wanted to control life into someone being led by The Way, God, the Dharma, the Tao… Take your pick.  And this being led was not an idea, but a physical letting go. A physical letting go which ushered me into a life of not understanding.  
In the monastery one becomes used to living and having no understanding of what is happening. We might be asked at any moment to do something we are totally unprepared for.  We become confortable with uncertainty, having no clue what is going on. We begin to live more in our bodies, more basic, fresh to our experience.  We are trained in a physical practice to realize how to function from a place of having no idea what is going on. In sanzen the Roshi would stop me if I reached out with my mind or If I tried to answer a koan from a mental place. If I tried to understand the practice mentally.  Every day he tapped his head and said: “Isn’t here”. 
This physical practice changes how we relate to reality. Just as we cannot hold on to anything in our sitting, the process cellularly molds us to be a being who does not hold on to anything off the cushion. In meditation and in functioning samadhi the mind cannot tighten into that place of grasping and understanding. Our connection to this true place becomes shallow when this happens.
So it is not that one develops to a certain advanced point and then the Mu Shin (No mind) develops out of that. It is that the Mu Shin is our natural way of being which molds us through the body to continually align with our true nature.
The practice shows us physically that we can’t do it.  We can’t make it happen.  We can’t figure it out. There is a process moving through us and that process takes over. It spills into everything in our lives.  We can’t reach out. We can’t constrict the moment with our thoughts. This alchemy takes over, and this essence, this deeper harmonizing expands out of us and takes over, and that is the very same Mu Shin.  The mind that extends to everything around it is not an idea but this very fullness which shines through us when we let go of the calculating mind.
Through the Roshi we saw the power of someone who did not reach out. Saw the fullness of someone receiving, the fullness which manifests form this place of Mushin.  And we too got a sense of that fullness which arises out of not reaching out.
Practically it feels full, like buoyancy. This buoyancy does the work. This buoyancy creates momentum for the internal alchemy. This fullness is the very mind shining.  It cleans us out, purifies us.  We become these internal alchemy machines. And when we go back, slip into our mental games, or try to figure out life, we find ourselves clogged up. Again, especially at first, the thoughts and the thinking are a form of clogging this great buoyancy. So we are left with nothing but a life of Mu Shin, a life of not understanding, but of getting everything done.
Gifts emerge like great intuition out of this not reaching out. We begin to sense the thoughts of others as we feel into the room. Our awareness fills the room as we do not reach out.  We jump up to answer the phone before it rings.  We’re standing on top of reality!  Because we are not using our brains to navigate, something else fills the room. A lightness, a joy, a liberation emerges as a matter of course.  A new type of clear functioning blossoms out of this fullness emerging. A light pervades our everyday activity. It’s bewildering at first!  But it becomes the only way, as this internal process takes hold.  
What emerges through this letting go is the same thing that is actually holding our bodies up as we stand there.  And if we let go into this true mind and are honest enough, we may finally truly touch the source of this great life energy for the first time, and have a great kensho. And then we will have no doubt. 
I’ve been doing this a long time, and have had a good chunk of time to digest the practice. It gave me a clear practice/path to feast on every day, to refine and chew on while I slowly ripen.  Big openings I had decades ago keep clarifying with practice. Slowly, sometimes messily, I am overthrown, molded by this felt sense practice bleeding through me. Over time it has become the green light to everything I do.  For some of you similar species out there, maybe you will bring your artistic sensitivity to this physical practice and realize something similar. Can we truly taste this huge river, our true shining mind?  
It’s been so wonderful to see people I have been working with get a sense of this connection. For me, feeling the body has been a clear practical path to discovering this Mu Shin (No Mind).  Once we get it, a new freedom begins.  Thanks for reading.  I hope this has been helpful for some of you. Please keep going!  You can do it!
Some words or phrases that I use in my classes (and some words I heard in sanzen many times) to help people feel into this process:
Don’t reach out!
Get the ki flowing and the deeper states of mind will naturally follow
No Inside No Outside
Get out of the way
Muko e Ja nai!  (It’s not over there!)
What is trying to happen?
Don’t chase shadows!
A Blank canvas!
Coming Coming Coming Coming
Like a Great Mountain!
Put the awareness back in the tanden
How is the tanden involved in that is happening?
Gives ourselves to the central channel
Melt into the room
Remove the barrier between self and other
It’s okay if you don’t understand
Don’t pin down this process trying to understand it
You are living right here, right now!
Let the horses run free
Don’t make it small
Let this process transform you
by Eikoh Hosoe 1968