Shoyoroku - Case 6: Master Ba's "White and Black" [1]

A monk asked Great Master Ba,
   "Apart from the Four Phrases, beyond one hundred Negations, please
    tell me directly, Master, the meaning of Bodhidharma's coming from
    the West."
Master Ba said,
   "I am tired today, I can't explain it to you. Go and ask Chizo."
The monk asked Chizo about it. Chizo said,
   "Why don't you ask our master?"
The monk said,
   "He told me to ask you."
Chizo said,
   "I have a headache today, I can't explain it to you. Go and ask Brother Kai."
The monk asked Brother Kai about it. Kai said,
   "I don't understand nothing about that question."
The monk told Great Master Ba about it. Great Master said,
   "Chizo's head is white, Kai's head is black."

[1]: see case 73 of Hekiganroku.