Zazen (sitting meditation) is so central to Zen practice that the two are often thought to be one and the same. In Soto-shu Zen, it forms the bulk of training and zazen itself is equated with satori, or enlightenment. Dogen, the founder of Soto-shu, gives detailed instructions for the correct performance of zazen, after describing the sitting position, he goes on: "Now that your posture is in order, regulate your breathing. If a thought arises, take note of it and dismiss it. If you practice in this way for a long time, you will forget all attachments and concentration will come naturally. That is the art of zazen. Zazen is the Dharma gate of great rest and joy."
The zazen technique itself is extremely simple, and requires no rituals or complicated mantra (words or phrases which are chanted as objects of meditation). Beginners should concentrate on their breathing, counting cycles of ten breaths for the duration of a period of 40 or 50 minutes. A slightly more advanced practice is to follow the breaths without counting them. Finally, the most difficult form of zazen taught by Dogen is shikantaza (nothing but simply sitting), which does not employ any focus such as the breath. In Soto-shu zendo, sitters face a plain wall (mempeki) in commemoration of Bodhidharma's nine-year meditation facing a cave wall.