"Never his mind on where he was, what he was doing..."- Yoda
Luke Skywalker learned the art of mindful breathing on his first visit to Dagobah. While climbing up vines, dashing through the undergrowth, leaping logs and rocks, the young Jedi pupil, his master on his back, is being instructed on the dangers of the dark side of the force. As Luke's mind races with a thousand questions about the dark side, it is clear to Master Yoda that Luke has lost touch with the here and now. "Nothing more will I teach you today," Yoda says. "Clear your mind of Questions."
Mindful breathing is simply the practice of concentrating on the breath. With the inhalation, you know that you are breathing in. With the exhalation, you know you are breathing out. You follow the breath in with awareness as it goes in, and you follow it as it goes out. You notice that the breath is long or short when it is long or short. With mindful breathing you just notice the breath; you do not try to hold it or force it; you do not alter its rhythm or change its volume. Don't hold on to the idea that you should breathe a certain way. Simply become aware of the way your body naturally breathes.
As we focus on our breathing we discover that our mind does not easily stay attuned to our breath, but flies off in a million different directions. Often we have concerns about a future event or confusion about the way something works and our mind becomes lost in a labyrinth of questions, doubts, and plans. Aware of this tendency, Yoda stops Luke before he can become bewildered, rather than empowered, by his education and training. By directing Luke to clear his mind of questions, Yoda is instructing the boy to come back to the present moment - to return to his breath. Luke does as he is told and almost instantly he is visibly calmer.
- from "The Dharma of Star Wars" by Matthew Bortolin