Vijnana Bhairava Tantra · Dharana 3 · Verse 26
The still center of the breath
Do not hunt for the pause. Let the breath run until the gap shows itself: the brief interval when there is neither in-breath nor out-breath. Rest there. Thought tends to go quiet in that interval, because it has no moving object left to follow.
Older line
When the center opens, the power that moves as breath neither goes out nor comes in. In that middle, free of thought, the nature of Bhairava appears.