Kinhin is the walking meditation done between periods of zazen. Practitioners walk in a line around the meditation hall, bringing the same attention to each step that they brought to each breath while sitting.
The pace varies between schools. In Soto Zen it is very slow, often half a step with each breath. In Rinzai Zen it can be brisk. The hands are usually held together at the chest.
Kinhin rests the legs and wakes the body, and it carries a quiet lesson: meditation is not confined to the cushion. Attention can move with you.