Working on Mu

One of the few books about Zen that I recommend you is Zen Training: Methods and Philosophy by Katsuki Sekida, and I once already referred to the chapter 'Working on Mu', now you can reread it.

What is Mu? This is the first koan, and Sekida gives the answer: '"Mu" means "nothing"'. And he is right: there is no point to hide the answer since you have to prove your competence only to yourself; and the answer, I believe, should be even more specific because Mu is the basis on which the further practice is built.

Synchronization of Body Movements with Breathing

This is also called synchronization of mind and body. Stand up straight and imagine that you're holding an imaginary scythe; imagine you're mowing grass with it. As you inhale, decide what to do (to make a stroke with the scythe); on an exhale, realize your decision: make this stroke.

This is the general principle: the most strong punch, for example, you can make on an exhale, so when you do squats or push-ups, inhale as you go down and exhale as you go up. But there is an exception: for the highest or longest jump, do it on an inhale.

When sweeping the floor, for instance, decide what to do on an inhale - to make several, 4 or 5, strokes with the broom - and as you exhale by the Bamboo Method, do this strokes. This is a sort of zazen: a good way to concentrate and a training for other exercises I'm going to describe further.

PS I don't encourage you to synchronize breathing with body movements throughout all your everyday life; as for me, I do it only when I'm on my own. 

The Bamboo Method of Exhalation

I usually use the Bamboo Method of Exhalation when I do sitting or walking zazen. You can read more about it here (page 71). If you're a beginner, then skip about Mu: 'The method is to say, in one breath, with intermittent or wavelike exhalation. We hit upon the name "bamboo method" for this type of exhalation, for just as a bamboo trunk has successive joints or nodes, so exhalation is stopped now... and then for a little while, giving short pauses...' That's all you need to know if you're a beginner.

I usually exhale through pursed lips to create tension in the tanden.