Zazen, literally 'seated Zen,' is the central practice of the Zen tradition. It was handed down from Bodhidharma's legendary nine years of wall-gazing to the Japanese masters Dogen, Rinzai, and Bankei, and into the modern world through teachers like Shunryu Suzuki, who came to San Francisco in 1959 and founded the San Francisco Zen Center. Vipassana is a technique aimed at producing insight. The Soto Zen approach of shikantaza, meaning 'just sitting,' a term Dogen coined in 13th-century Japan, makes no such goal. Shikantaza is not a practice you do to reach enlightenment. Shikantaza is enlightenment expressing itself. The sitting is the awakening. There is nothing to reach and nowhere to go. You sit in the posture of a Buddha because you already are one, not as a hope but as a fact you are recognizing.
The posture of zazen is exact. You sit in full lotus (each foot on the opposite thigh), half lotus (one foot on the opposite thigh), or seiza (kneeling with a cushion between your legs). The spine is fully upright, not stiff but naturally straight. The hands form the cosmic mudra: the left hand rests in the right, thumbs lightly touching, held below the navel. The eyes stay half-open, looking down at about a 45-degree angle. Zen is practiced with the eyes open, keeping contact with the world while you watch your inner landscape. Breathing is natural. In shikantaza there is no object to meditate on. You do not focus on the breath, a mantra, a sensation, or a question. You simply sit, fully awake, with your awareness wide open and taking in everything without getting caught by anything. Dogen's instruction sounds like a riddle: 'think of not-thinking. How do you think of not-thinking? Beyond-thinking.'
The Rinzai school of Zen, brought to Japan by Eisai in the 12th century and carried to the West by teachers like Joshu Sasaki Roshi and Shodo Harada Roshi, uses a different method: the koan. A koan is a question or statement a teacher gives a student that ordinary logical thinking cannot answer. The most famous one in the West is Hakuin Ekaku's 'What is the sound of one hand clapping?' though Hakuin's original was simply 'What is the sound of one hand?' The student is told to carry the koan into their sitting, their daily life, even their dreams, to make it the one thing the whole body is chewing on until the answer breaks through from somewhere below the thinking mind. The answer to a koan is not a thought. It is a direct show of insight. In a formal interview called dokusan, the student presents their understanding, in body, energy, and words, and the teacher either rings the bell (correct) or does not. Many students work on a single koan for months or years.
The Rinzai koan system has more than 1,700 cases, arranged as a step-by-step curriculum. It starts with a first breakthrough koan (usually Joshu's 'Mu,' which asks about the Buddha-nature of a dog) and moves through ever-subtler questions about the nature of mind, self, time, and reality. The point is not intellectual understanding. A student who gives a clever philosophical analysis of 'Mu' is turned away. The point is satori: a sudden, non-conceptual flash of direct insight into the nature of awareness itself. Satori is not full enlightenment in the complete Buddhist sense. It is a glimpse. But the glimpse permanently changes how the practitioner relates to experience. Many who have had satori describe it as realizing that what they were looking for was the very thing doing the looking.