Starting 7 December 2012, I sat in a short 3 days retreat led by Jon and Will Kabat-Zinn. I made a huge stride forward. During the retreat, I became able to arrive at that mind of no-thought repeatedly, and each instance a little longer than it normally would (but still short enough to qualify as "a moment"). I investigated that mind and found that it has 3 features:
1. "Direct experiencing" is very strong, specifically the experience of sensation. There is brain science that shows the "direct experience" network to be mutually exclusive to the "narrative" network in the brain, and I think I have discovered it experientially.
2. Specifically, audio sensitivity is very high. In that mind, I became very sensitive to sound. At first, I wasn't sure of the direction of causality, I thought it was attention to the sound that led to the mind of no-thought, since I was close to a water fountain at the time. So I moved far away from it to a "quiet" spot and found that, in that mind, I became very sensitive to the air conditioning sound. Hence, it seems like the no-thought mind lead to heightened audio sensitivity.
3. Seeing without seeing. I had a very strange visual experience, which I could describe only as "seeing without seeing". I could clearly see, but I could not perceive visually. I investigated it and figured out what happened. In that mind of no-thought, the gaze of the eyes was fixated on one spot. I realized that when we "see" a scene, the eyes are actually scanning the entire scene and then the mind forms a mental picture. When the gaze is fixated, the mind could not form the mental picture and hence it did not "see". When I returned to seeing "normally" (ie, allowing the eyes to scan the scene), that subtle activity alone was enough to break the no-thought mind.
And then I realized something more profound. I realized that what Jon Kabat-Zinn calls "awarenessing", which is being here now and attending entirely to the present (especially to sensations) creates the conditions for no-thought mind, which in turn creates the conditions for quietness of mind, which then creates the conditions for samadhi (concentration and serenity).
In other words, "awarenessing" is the secret ingredient in developing the ability to completely quiet one's mind of thought. Wow.
Given that insight, I wrote to myself:
Having nowhere to go and nothing to do.
Sensual excesses vigilantly restrained.
Generously treating all with kindness.
Mind is ready.
Letting go of all past and future.
Joyously mindful of this present moment,
I allow the mind to settle on its own.
Letting go of all desire to restrain the mind.
Just letting it settle on its own.
In whichever way it wants.
In its own time.
Thus, applying skillful effort,
Samadhi arises effortlessly.
(Since March 2013, so many things have been happening in my "real life" that I temporarily lost the ability to completely quiet my mind of thought, but happily, I know how to regain that ability as my practice deepens to match the increased challenges in my "real life".)
Update (2013/06/17): The great Shinzen Young comments on this. See link.