The body-mind
Laying down the body here, shed the body there. How is it there? Step by step, the practice is intimate and continuous. How is it here? The whole heart beats, moment by moment.
Dōgen, Eihei Kōroku.
The body here: My ordinary body, sitting in posture. The body there: stripped of the ordinary body (ego).
Body and mind are stripped of themselves (shinjin datsuraku), in both meanings of the pronoun: the body-mind sheds itself as a snake sheds its own skin. And it sheds itself spontaneously, without external help. There is no "I" trying to strip the "me." It just happens.
Letting go
In zazen, there is nothing to do, just letting go. Letting go of what? Of the moment, just as it is, without resistance or desire. Letting go into the flow of the breath, into the posture, into the silence. Letting go by allowing thoughts and emotions to be as they are: letting them appear and disappear like clouds. The mountain is not hindered by the clouds; the clouds do not remain on the mountain.
Beyond thinking
Letting go is not about giving up, but about opening to the experience of presence, full and empty at the same time. Just sit!
Once a monk asked Yaoshan [745-827]: What are you thinking while in steadfast, immovable sitting? Yaoshan said: I think of not thinking. The monk said: How do you think of not thinking? Yaoshan said: Beyond thinking.
Dōgen, Eihei Kōroku.
Even in deep contemplation (samādhi), the brain continues to produce thoughts. But through ongoing zazen practice, thoughts gradually fade and may dissolve into a kind of thinking beyond ordinary thought, into a vast thought, free from mental obstruction.
Just watch thoughts arise and disappear, without being carried away by them, without analyzing, interpreting, or judging them. To think without thinking is a bit like hearing without listening, seeing without looking. Consciousness is vast, it clings to no sensory perception, no emotion, no thought.
The whole body-mind is one vast, objectless perception.