The Gateless Gate, by Ekai, called Mu-mon, tr. Nyogen Senzaki and Paul Reps [1934], at sacred-texts.com
Amban, a layman Zen student, said: "Mu-mon has just published forty-eight koans and called the book Gateless Gate. He criticizes the old patriarchs’ words and actions. I think he is very mischievous. He is like an old doughnut seller trying to catch a passerby to force his doughnuts down his mouth. The customer can neither swallow nor spit out the doughnuts, and this causes suffering. Mu-mon has annoyed everyone enough, so I think I shall add one more as a bargain. I wonder if he himself can eat this bargain. If he can, and digest it well, it will be fine, but if not, we will have to put it back into the frying pan with his forty-eight also and cook them again. Mu-mon, you eat first, before someone else does:
"Buddha, according to a sutra, once said: 'Stop, stop. Do not speak. The ultimate truth is not even to think.'"
Amban's comment: Where did that so-called teaching come from? How is it that one could not even think it? Suppose someone spoke about it then what became of it? Buddha himself was a great chatterbox and in this sutra spoke contrarily. Because of this, persons like Mu-mon appear afterwards in China and make useless doughnuts, annoying people. What shall we do after all? I will show you.
Then Amban put his palms together, folded his hands, and said: "Stop, stop. Do not speak. The ultimate truth is not even to think. And now I will make a little circle on the sutra with my finger and add that five thousand other sutras and Vimalakirti's gateless gate all are here!"