Dragon Murmurings (BCR2)

KOAN:

A student asked Xingyiang, “What is the Way?”
Xiangyan said, “Dragon murmurings in a withered tree.”
“What is a person of the Way?”
“Eyes in a skull.”
Later, the student asked Xishuang, “What are ‘dragon murmurings in a withered tree’?”
Xishuang replied, “I still have joy.”
Later still, the student asked Caoshan, “Who can hear these dragon murmurings?”
Caoshan replied, “There is no one in the world who isn’t hearing it.”
“What book is ‘dragon murmurings in a withered tree’ from?”
“I don’t know what book it’s from, but everyone who hears it dies.”

—from Xuedou’s verse commentary on Blue Cliff Record Case 2