There's a commonly observed "Zen" content to stillness. This is a stillness gone into itself-a meditative mode. However, there are other ways of being or becoming still. Note these three states:
A Stillness as arrest B Stillness as a state C Breaking out of stillness
The Zen of Stillness concerns B - a composed state which deepens when one adopts a position which is easy to hold for a long time. The Zen endures, perhaps from the beginning to the end of the piece. Perhaps it begins before the beginning and ends after the audience have gone.