An explanation of the Koan answer
A simple Koan.
If somebody asks something like: What is Zen, the Buddha, the Way etc. the master will answer "mystically". Just repeat the master's words. He is supposed to be enlightened. Repeat the master's words, to express that he (or she) is your role model.
The background story of this Koan
There is no background story for this Koan.
Despite the student expecting a theoretical explanation the master answers like a mystic to confuse the student's mind.
"Mystification" of reality to show enlightenment is quite common in Japanese Zen.
In this case a sinologist (McRhae) discovered a Chinese explanation for this Koan, which shows how misleading the Japanese mystification is.
In medieval China the Chan (Zen) monks were called "little Buddhas". Every year the emperor provided a certain amount of flax for each monk.
That's what Tozan satirically refers to, when he was asked what is Buddha: Those monks who get their robes provided by the emperor!
The remark was critical as well, for monks were supposed to stay away from the authorities. This was already a teaching of Taoism.
Traditional Commentaries and .... Poems (Gata)
Old Tozan's Zen is like a clam. The minute the shell opens you see the whole inside.
However, I want to ask you: Do you see the real Tozan?
Old man Dongshan was able to interview with some clam Ch’an.
He only opened a little bit but revealed and put forth his liver and intestines.
So, although you indeed listen, just say what place do you face to see Dongshan?