Zazen (meditation) is a fundamental method of training in Zen Buddhism, in which one meditates sitting with correct posture. It is sometimes written with the characters 座禅 however it is correct to use the character 坐.
Harmonize posture, breathing and mind. (choshin, chosoku, choshin respectively)
A special cushion for Zazen called a zafu is used when sitting down to meditate. A zabuton (flat cushion) folded in two can sometimes serve as a substitute. Sit down cross-legged on the cushion, with knees barely touching the floor.
Zazen is done in either full-lotus position or half-lotus position. To sit in the full-lotus position, put the right foot on the left thigh and move the right heel close to the hip. Next, put the left foot on the right thigh. In half-lotus position only the left foot is put on the right thigh. In either position, the three points including two legs and bottom make a balanced sitting posture.
The hands are placed together palms up with the thumbs touching in a natural arc in the hokkai-join or gesture of reality. Face the right palm upwards and place the left palm on top. Lightly touch the tips of the thumbs together.
With eyes half open, lower gaze to a point about one meter in front.
Pull chin in, and rest the tongue lightly on the roof of the mouth behind the front teeth, keeping mouth lightly closed.
Relax shoulders and straighten the spine. Pull the back in and the stomach slightly forward. Such that the nose and navel are in line.
Breathe naturally. Breathe out and in gently from the nose. It is said to exhale from the 'tanden' (a point in the lower abdomen).
Some temples hold zazen meetings.
Also, the correct way to do zazen is broadcast on A and available for viewing free.
Zazen is sometimes perceived as the same as visual meditation ('meiso'), however the direction of zazen is different to that of visual meditation in which the eyes are closed and an object is visualized in the mind. The purpose of zazen is not to be bound by the images in your mind but to experience the world and yourself as it really is, and reach a spiritual place of nothingness.
The priest Dogen, founder of the Soto Sect of Buddhism, emphasized the concept of 'shikantaza' which is a Japanese term for zazen and means just sitting. It means to just sit for the sake of sitting, and not for the purpose of gaining some merit or reward.
Medical researchers are studying the slowing of breathing during zazen meditation.