Hello all,

I am currently reading 'Zen Training' by Katsuki Sekida and am finding it interesting (and a little confusing) how he speaks about breathing in zazen.

To quote (p32):

"In zazen, we breathe almost entirely by means of our abdominal muscles and diaphragm. The muscles of the thorax are scarcely used. If the lower abdomen is allowed to fill out, the diaphragm is lowered, the thoracic cavity is enlarged, and air is taken into the lungs. When the abdominal muscles contract, the contents of the abdomen are pushed up, which in turn forces the diaphragm up, reducing the volume of the thoracic cavity and expelling air from the lungs. The slow, sustained exhalation that we adopt in zazen is produced by keeping the diaphragm contracted so that it opposes the action of the abdominal muscles, and the maintenance of this state of tension is of utmost importance in the practice of zazen. All other parts of the body are motionless, and their muscles are either relaxed or in a state of constant, moderate tension. Only the abdominal muscles are active. I ways that we will explain later, this activity is a vital part of the mechanisms by which concentration and wakefulness of the brain are maintained. Traditionally in the East, the lower part of the abdomen (called the tanden) has been regarded as the seat of spiritual power. Correct zazen posture ensures that the weight of the body is concentrated there, producing a strong tension, and the method of breathing that is adopted reinforces that tension."

How important is this advice? When I sit, I usually slowly breathe a number of times into my lower belly when I begin to release some degree of tension but then let breathing look after itself. Even if I am tense and breathing relatively shallowly to start off with, the breath rarely fails to deepen as sitting lengthens.

The question is, do I need to be paying more attention to this aspect of sitting?