The room where you do zazen should be as quiet as possible. It should be neither too light nor too dark and should be warm in the winter and cool in the summer.
Lay down a large flat cushion, a zabuton, facing a wall, and on top of that, place a zafu, a round, firm cushion. Sit down on the zafu and fold your legs. Cross them by putting your right foot on your left thigh and then your left foot on your right thigh. This is called the full-lotus posture. If you are unable to fold your legs in this way, simply place your left foot on your right thigh. This is called the half-lotus posture. Sit on the front part of the zafu, not on the middle of it, for the sake of good blood circulation. The zafu should be behind the place where your legs cross, and your knees should be firmly down on the zabuton. The weight of the upper part of the body should be distributed on three points—both knees on the zabuton and your buttocks on the zafu.
Sit up, straighten your back, with your buttocks naturally but firmly pushing outward. Keep your neck straight and pull in your chin. Without leaving an air pocket, close your mouth and put your tongue firmly against the upper palate. Project the top of your head as if it were going to pierce the ceiling. Relax your shoulders. Place your right hand on top of your left foot (palm up) and place your left hand in the palm of the right. Your thumbs should touch just above your palms.
Your ears should be in line with your shoulders, and your nose should line up with your navel. Keeping your eyes open as usual, look at the wall and drop your line of vision slightly.
Once you have taken the zazen position, open your mouth and exhale deeply. In order to work out the stiffness in your joints and muscles, slowly swing two or three times to the left and right, finally settling in an unmoving, upright posture. Once you have taken this immovable posture, breathe quietly through your nose.
Doing correct zazen means taking the correct posture and entrusting everything to it.
Excerpted from Opening the Hand of Thought, by Kosho Uchiyama.
