Caodong (Chinese 曹洞宗) is a Chinese Zen Buddhist sect founded by Dongshan Liangjie and his Dharma-heirs in the 9th century. Some attribute the name "Caodong" as a union of "Dongshan" and "Caoshan" from one of his Dharma-heirs, Caoshan Benji; however, the "Cao" much more likely came from "Caoxi", the "mountain-name" of Huineng, the Sixth Ancestor of Chan, as Caoshan was of little importance unlike his contemporary and fellow Dharma-heir, Yunju Daoying. The sect emphasised sitting meditation, and later "silent illumination" techniques.
In 1227 Dogen Zenji took Caodong to Japan as the Soto sect, where it became very popular.
- Caoshan Benji (9th century)
- Dongshan Liangjie (9th century)
- Hongzhi Zhengjue (12th century)