The Sōtō-shū (from the Chinese 曹洞宗, "Caodong") is one of the three famous Japanese Zen sects. It is an extension or subbranch of the Chinese Caodong, which was brought to Japan by Dogen Zenji (1200-1253), and which after his death became known as the Sōtō school.
With 14,700 temples and nearly 7 million adherents (in 1989) Sōtō is the largest Zen sect in Japan, surpassing Rinzai and Obaku. In Japanese history, Sōtō gained ground among provincial rulers and ordinary people, while Rinzai won the support of the central samurai government. Sōtō is practised both in Japan and in the West, and stresses shikantaza, the meditation in simply sitting in a fixed posture. Sitting is not seen as the means to an end, but as an end in itself, a direct means of expressing enlightenment and Buddhahood in an instant.
The characteristics of Sōtō as a distinct style of Zen go back to Shih-t'ou Hsi-ch'ien (J. Sekito Kisen, 700-790) who led an important practice center in the mountains of Hunan province in China. From this school there developed three different schools of Zen of which Sōtō is one. However, the school was founded by Tung-shan Liang-chieh (807-69) in China. Its transmission to Japan was done by Eihei Dogen Zenji (1200-1253). Up till today, comparable to the tibetan system, every now and then an older monk is chosen as the new lineage bearer. This monk has to be an enlightened zen-master as well as living for at least +/- 15 years in a zen-monastery. This lineage goes back to Gautama Buddha, the Buddha and founder of Buddhism.
Shih-t'ou Hsi-ch'ien's poem "The Harmony of Difference and Sameness" is an important early expression of Zen Buddhism and is chanted in Sōtō temples to this day. One of the poems of Tung-shan Liang-chieh, the founder of Soto, is "The Song of the Jewel Mirror Awareness" is also still chanted in Sōtō temples. Another set of his poems on the Five Positions of Absolute and Relative is important as a set of koans used in the Rinzai school. Dogen's teaching is characterized by the identification of practice as enlightenment itself. This is to be found in the Shobogenzo.