Shoyoroku - Case 10: An Old Woman near Taizan [1]

There was an old woman on the way to Taizan. Whenever a monk asked her how to
get to Taizan, she would answer, "Go straight on." After the monk had gone a
few steps, she would say, "This good and naïve fellow goes off that way, too."
Later a monk told Joshu about this. Joshu said, 
  "Wait a bit. I will go and see through her for you."
He went and asked the same question. The next day, Joshu ascended the rostrum
and said,
  "I have seen through the old woman for you."

[1]: see case 31 of Mumonkan.