What Is Emptiness?

The current issue of the Buddhist Review TRICYCLE (spring 2010) has an article on using sleep states to practice. Of course this caught my interest, as I am an all nap all the time kind of person. But what interested me the most is a tiny poem by Natalie Goldberg called “What Is Zen Anyway?” The poem itself: “A Japanese corpse/serving tea.”
So what is going on here? First off, I want to know the answer too. What is Zen? At least sometimes. Sometimes I don’t care at all. That Japanese corpse might be Katagiri-roshi, Nat’s teacher. It might be something long gone and dead and unfamiliar. It might be something suddenly animated, like the stone woman in the koan who gives birth in the night.
Serving tea I get–this is the world of form. So perhaps emptiness has invited me to tea. Emptiness seems easy to intuit or scent or even taste, but hard to talk about.
I’m in a koan salon with Joan Sutherland-roshi. These past few weeks in New Mexico fruit trees have bloomed, and then it has snowed and hailed. What is serving me tea? What is emptiness?