Caodong school
During the 12th century, a clear difference between the Linji and the Caodong schools emerged. The two schools were competing for support of the literati, who became more powerful when the Song-government started to limit her influence on society. Hongzhi Zhengjue (1091–1157) of the Caodong-school emphasized silent illumination or shikantaza as a means for solitary practice, which could be undertaken by lay-followers. Dahui Zonggao (1089–1163) introduced kanhua practice, "observing the word-head", as a means of solitary practice. He organized the study of koans into a system, which was exported to Japan in this period.