The Sōtō school of Zen descended from the Chinese Caodong tradition, which traces its origin to the teachings of Bodhidharma, a legendary monk who came from India in the early fifth century. He taught simple seated meditation as the path to realization, diminishing the importance of words and scriptures. Bodhidharma was succeeded by generations of patriarchs, each conveying the essence of the teachings to his successor by the intimate interaction of teacher and disciple. These teachings and forms comprised the core of Chan Buddhism, informing all the schools and tendencies that developed over the years as Chan became the predominant form of Buddhism in China.
The Caodong school of Chan found its way to Japan in the 13th century, brought there by Eihei Dogen, a Japanese Buddhist monk. Dogen had made the perilous journey to China in search of a Buddhist practice more genuine than what he had found in his native country. For two years he traveled through eastern China from one temple to another, searching for a worthy teacher, before settling at Mount Tiantong in Ningbo. There he studied for more than two years with a master named Rujing (Nyojo in Japanese), receiving dharma transmission before returning to Japan. He brought with him the conviction, instilled by Rujing, that shikantaza--just sitting--is the only essential practice for realizing the true teaching of Shakyamuni Buddha.
Dogen taught and wrote for the next 25 years, eventually founding a temple called Eiheiji--Temple of Eternal Peace--which remains one of the two head temples of Sōtō Zen. Dogen's teaching has also lasted through the centuries, today still providing the foundation for practice at Zen centers around the world.