Tzu Hu studied under Nan Ch'uan. He was a fellow student of Chao-chou and Tiger Ts'en [Ch'ang Sha]. At that time, Iron Grinder Liu had set up a hut on Mt. Keui. People from all over couldn't cope with her.
One day Tzu Hu came proudly to call on her. He asked, "You're Iron Grinder Liu, aren't you?"
The Grinder said, "I don't presume to say so."
Tzu Hu said, "Do you turn to the left or turn to the right?"
The Grinder said, "Don't tip over, Teacher."
Hu struck her while her words were still in the air.
Hseuh Tou comments, in part:
Tzu Hu had to hit Iron Grindstone Liu.