The magic of drawing is in the strokes. By strokes I mean the unique quality of the lines or other marks the artist makes. Some lines jab while others meander. Some markings are blurred while others are crisp. The strokes convey in a tactile way the essence of how the artist comes to grips with the challenge of capturing an actual thing or manifesting an inner vision. Making a drawing is a journey of exploration, and the marks are evidence of the journey. When we look at a drawing, we can feel the energy that went into it in the particular lines and strokes.
“Self Portrait”
R L Benoit - Writer/Artist 
ensō (円相 , “circle”?) is a circle that is hand-drawn in one or two uninhibited brushstrokes to express a moment when the mind is free to let the body create.
This must be a Japanese term. I had not heard it but now that I have I understand it. It comes from practicing until the artist needs no intellectual thought to create. They just do it.