Hekiganroku - Case 98: Tempyo's Two "Wrong"s

Master Tempyo was on an angya [1] and visited Sai'in. (He was always saying,
"Don't say you have understood Buddhism. I have sought after someone who
could give correct explanations, but in vain.")
One day, Sai'in saw him at a distance and summoned him,
  "Jyui! [2]"
Tempyo raised his head. Sai'in said,
  "Wrong!"
Tempyo went on a couple more steps. Sai'in said again,
  "Wrong!" 
Tempyo came closer. Sai'in said,
  "I have just said, 'Wrong!' twice. Does it mean that it is I
   who am wrong, or it is you?"
Tempyo said, 
  "It is I."
Sai'in said,
  "Wrong!"
Tempyo said nothing. Sai'in said,
  "Please stay here for the summer [3]. I'll examine the two 'Wrong!'s with
   you."
However, Tempyo immediately left him.

Later he was the abbot of his own temple and said to his assembly,
  "As I was once on an angya, I was driven by the wind of fate and came to
   Elder Shimyo [4], who cried to me, 'Wrong!'. Moreover, he demanded that
   I stay with him for the summer to examine this matter with him. I didn't
   believe I had done anything wrong then. But when I was on my way down
   south, I realized quickly that I had done something entirely 'wrong'."

[1]: A traditional pilgrimage in order to deepen the practice.
[2]: Tempyo's personal name.
[3]: I.e., a summer sesshin for three months.
[4]: I.e., Sai'in.