Soutou Zen, or the Soutou school is (with Rinzai and oubaku), one of three sects of Zen in Japanese Buddhism.
The Soutou sect was first established as the Caodong sect during the Tang Dynasty in China by Dongshan Liangjie in the 9th century, which Dogen Zenji then brought to Japan in the 13th century. Dogen is remembered today as the co-patriarch of Soutou Zen in Japan along with Keizan Joukin. One of the signature features of this school is found in its practice of shikantaza, a particular approach to zazen which is sometimes referred to as "just sitting" or "silent illumination." Historically speaking, Soto Zen was often given the derogatory term "farmer Zen" because of its mass appeal, while the Rinzai school was often called "samurai Zen" because of the larger samurai following. The latter term for the Rinzai can be somewhat misleading, however, as the Soto school also had samurai amidst its rosters.
The two head temples of the Soutou sect are Eiheiji and Souji-ji. While Eiheiji owes its existence to Dogen, throughout history this head temple has had significantly less sub-temple affiliates than the Souji-ji. During the Tokugawa period, Eiheiji had approximately 1,300 affiliate temples compared to Souji-ji's 16,200. Furthermore, out of the more than 14,000 temples of the Soto sect today―13,850 of those identify themselves as affiliates of Souji-ji. Additionally, most of the some 148 temples that are affiliates of Eiheiji today are only minor temples located in Hokkaido―founded during a period of colonization during the Meiji period. Therefore, it is often said that Eiheiji is a head temple only in the sense that it is "head of all Soutou dharma lineages."