The Gateless Gate, by Ekai, called Mu-mon, tr. Nyogen Senzaki and Paul Reps [1934], at sacred-texts.com
Nansen saw the monks of the eastern and western halls fighting over a cat. He seized the cat and told the monks: "If any of you say a good word, you can save the cat."
No one answered. So Nansen boldly cut the cat in two pieces.
That evening Joshu returned and Nansen told him about this. Joshu removed his sandals and, placing them on his head, walked out.
Nansen said: "If you had been there, you could have saved the cat."
Mumon's comment: Why did Joshu put his sandals on his head? If anyone answers this question, he will understand exactly how Nansen enforced the edict. If not, he should watch his own head.