Deshan Xuanjian lived during the eighth and ninth centuries in Northern China. One day he heard that in the South they were speaking about a “special transmission outside the scriptures.” Being a scholar himself—he was known as Diamond Shu because he was an expert on the Diamond Sutra—he thought he would travel south and put them all in their places. “Those who leave home may study the great meaning of Buddhism for a thousand eons and spend a further ten thousand eons performing detailed Buddhist practice, yet they still won’t become a buddha,” he said. “How dare those southern devils say that by just pointing at the human mind one can see self nature and attain buddhahood. I’ll go and drag them from their caves and exterminate their ilk and thus repay the kindness of the Buddha.”

With copies of the sutra commentaries on his back, Deshan set out. As he traveled, he came upon an old woman selling dumplings by the side of the road. Stopping to rest, Deshan asked if he could buy a small meal. The old woman pointed at his bundle and asked, “What are those books?” Deshan said, “They are sutra commentaries.” The old woman asked, “What sutra do they expound on?” Deshan responded, “The Diamond Sutra.” Then the old woman said, “I have a question for you. If you answer it correctly, then I’ll give the dumplings to you. If you can’t answer, then I won’t even serve you.” Of course Diamond Shu, the expert on the Diamond Sutra, did not hesitate for an instant. The old woman then said, “In the sutra it says, ‘Past mind cannot be grasped, present mind cannot be grasped, future mind cannot be grasped.’ What I want to know, monk, is which mind are you revealing right now?” And Deshan couldn’t answer. He then asked the woman, “Is there a Zen teacher around here?” At least he showed some life, but he still could not recognize the teacher standing right in front of him.

Now There’s a hot dog stand on Route 28 that’s run by a wonderful old woman. One afternoon, after she made my hot dog she sat on her little folding chair and just looked at the mountains. After a while she said, “You know, I lived in the city all my life, and now every morning when I come out the door”—she gestured to the mountains—“these mountains startle me.” I couldn’t help but wonder whether the depth of this vendor’s wisdom was much deeper than what was evident on the surface.

But Deshan didn’t recognize the old woman’s potential, so he asked her if she knew of a Zen teacher. The woman then sent him to see Longtan, and this is where the koan picks up.