Before Caoshan and Dongshan
Unique among the different chan teaching traditions in China, Cao-Dong School enjoys the distinction of having had something like a pre-history, extending back 100 years before the time of its official founders, Caoshan and Dongshan. In addition to tracing back a direct lineage to the Sixth Patriarch Huineng by way of the celebrated third-generation master Shitou Xiqian, and emphasizing the two great masters Yaoshan and Yunyan in the succession between Shitou and Dongshan, this recognition that Cao-Dong has its roots firmly planted in the earlier 8th century chan environment is also strengthened by thematic similarities in the recorded teachings of Dongshan and Shitou Xiqian.
Today, a visitor to Shitou's South Peak Temple (Nantai si) at South Mountain (Hengshan, or Nanyue) in Hunan Province will see a sign inscribed over the main gate announcing that one is entering an ancestor temple of Cao-Dong School. Another example of this 8th-century influence is the circumstance that for centuries in Japan, daily Soto zen ceremonies have included the chanting of Sandokai (The Agreement of Difference and Unity), a translation of Shitou's famous poem Can tong qi. The same poem is now chanted in Soto practice centers in Europe and America, providing evidence of a practice tradition extending without interruption almost 1200 years.