Passing along a wonderfully helpful article that explains the nature of breathing awareness, courtesy of Yoga International.
“There are many good methods of concentration bequeathed to us by our predecessors in Zen. The easiest for beginners is counting incoming and outgoing breaths. The value of this particular exercise lies in the fact that all reasoning is excluded and the discriminative mind put at rest. Thus the waves of thought are stilled and a gradual one-pointedness of mind achieved.” – Zen master Yasutani-Roshi (1885-1973)