The most famous of Dongshan's disciples was Caoshan (Ts'ao-shan) Benji. Together with his teacher they originated the Chan school of Caodong (Soto in Japan).
One exchange between master and disciple began with a question by Dongshan:
"What is your name?"
"My name is [Caoshan]."
"Say something toward Ultimate Reality.”
"I will not say anything."
"Why don't you speak of it?"
"It is not called [Caoshan]."
This anecdote seems to assert that the Universal cannot be reached through language, and hence he could only converse about his objective, physical form.
When Caoshan decided to strike out on his own, the older master then inquired:
"Where are you going?"
"I go where it is changeless."
"How can you go where it is changeless?"
"My going is no change."
Caoshan was inspired by Dongshan's "five ranks" as a method of instruction and expanded upon them. It was their wide use in Zen monasteries that helped differentiate Caodong Zen as a unique school. Because the Five Ranks seems not to have survived the Sung Dynasty, we will not examine the five ranks in this course.
Caoshan and Hanshan
Caoshan was known for Annotation on Poems of Hanshan. In fact, some think that some of the verse attributed to Hanshan were written by Caoshan, as he used his own poems to annotate those of Hanshan, and at some point the poems from his annotation and Hanshan's originals came to constitute what we now think of as the poems of Hanshan.