Between periods of sitting meditation, Chan monks stand and walk. Slowly. Deliberately. Each step a complete thought.
This is kinhin (經行), and it's not a break from practice. It is practice.
Why Walk?
Sitting meditation works with the mind directly. Walking meditation works with the mind through the body. And for many people, the body is a more honest teacher.
You can fool yourself about your mental state. You can't fool your feet. If you're anxious, your steps are quick and shallow. If you're scattered, your balance wavers. If you're present, your steps are steady and full.
How to Practice
Stand still. Feel your feet on the ground — the heel, the ball, the toes. Let your weight settle. Then begin.
Lift. Move. Place. That's the whole instruction. Lift one foot. Move it forward. Place it down. Feel the transfer of weight. Then the other foot.
Don't aim for slowness. Aim for completeness. Each step should be a whole step — not a fragment of walking, not a means of getting somewhere.
The Body Knows
The body doesn't have opinions about enlightenment. It doesn't wonder if it's doing it right. It just walks. And in that just-walking, the mind settles — not because you forced it, but because the body showed it how.
A Daily Practice
You don't need a meditation hall. Walk to the kitchen. Walk to the bathroom. Walk to the mailbox. Each walk is a complete universe of practice.
The Buddha attained enlightenment while sitting under a tree. But he walked for 45 years afterward.