Zazen — literally 'seated Zen' — is the central practice of the Zen tradition, transmitted from Bodhidharma's legendary nine-year wall-gazing to the Japanese masters Dogen, Rinzai, and Bankei, and into the modern world through teachers like Shunryu Suzuki, who arrived in San Francisco in 1959 and established the San Francisco Zen Center. Where Vipassana is a technique aimed at producing insight, the Soto Zen approach of shikantaza — 'just sitting,' a term coined by Dogen in 13th-century Japan — makes no such goal-oriented claim. Shikantaza is not a practice toward enlightenment. Shikantaza is the expression of enlightenment. The sitting is the awakening. There is nothing to achieve and nowhere to go. You sit in the posture of a Buddha because you are a Buddha — not as aspiration but as recognition.
The physical posture of zazen is precise. The practitioner sits either in full lotus (both feet on opposite thighs), half lotus (one foot on the opposite thigh), or seiza (kneeling with a cushion between the legs). The spine is fully erect — not rigid but naturally aligned. The hands form the cosmic mudra: left hand resting in the right, thumbs lightly touching, held below the navel. The eyes are half-open, cast downward at a 45-degree angle — Zen practice is done with eyes open, maintaining contact with the world while the inner landscape is observed. Breathing is natural. In shikantaza, there is no object of meditation. The meditator does not focus on the breath, a mantra, a sensation, or a question. The meditator simply sits, fully alert, with awareness open and inclusive of everything without being captured by anything. Dogen's instruction is strikingly counter-intuitive: 'think of not-thinking. How do you think of not-thinking? Beyond-thinking.'
The Rinzai school of Zen, established in Japan by Eisai in the 12th century and transmitted to the West through Rinzai teachers including Joshu Sasaki Roshi and Shodo Harada Roshi, employs a different method: the koan. A koan is a question or statement given by a teacher to a student that cannot be answered by ordinary conceptual thinking. The most famous koan in the Western world is Hakuin Ekaku's 'What is the sound of one hand clapping?' — though the original Hakuin formulation is simply 'What is the sound of one hand?' The student is instructed to take the koan into their sitting, into their daily life, into their dreams — to make it the central preoccupation of the entire organism until the answer breaks through from somewhere beneath the conceptual mind. The answer to a koan is not a thought. It is a direct demonstration of insight. In formal interview (dokusan) with the teacher, the student presents their understanding — physically, energetically, verbally — and the teacher either rings the bell (correct) or does not. Many students work on a single koan for months or years.
The koan system in Rinzai Zen comprises over 1,700 cases, organized into a progressive curriculum from the initial breakthrough koan (usually Joshu's 'Mu' — what is the Buddha-nature of a dog?) through increasingly subtle investigations of the nature of mind, self, time, and reality. The purpose is not intellectual understanding. A student who provides a philosophically sophisticated analysis of 'Mu' is dismissed. The purpose is satori — a sudden, non-conceptual breakthrough of direct insight into the nature of awareness itself. Satori is not enlightenment in the full Buddhist sense; it is a glimpse. But the glimpse reorganizes the practitioner's relationship to experience permanently. Many who have experienced satori describe it as the recognition that what they were seeking was what was seeking.