Life is defined by breath. The first breath and last breath, and all in between. The quality of the breath depends on the body and the mind. When we are on a relaxed state we can breathe all the way to the belly or in fact anywhere we choose.
When we are in stress the breath will be shallow, frequent and in the shoulders and possibly upper chest.
Breath is a thread that connects all life on this planet. Making the most of the breath in a meditation practice is honestly the trick to a steady regular practice. It is what takes you in and what brings you out of your practice. In this way we commence the session by simply focusing on our breath. Creating a regular pattern. Reducing areas of tension. Creating space where previously there was a limitation.
Acknowledging and then focusing on the breath is the beginning of the practice (the actual practice ) and the end, the moment you exit a practice. We also go to the breath (renew the connection to the breath) many many times when in meditation. When the mind gets in the way breath can be there to settle the mind and bring us back into the rhythm of a practice.
We sit with our eyes partially closed and turn our attention to our breathing. We breathe naturally, preferably through the nostrils, without attempting to control our breath, and we try to become aware of the sensation of the breath as it enters and leaves the nostrils.