A huatou, Chan master Xuyun (1839-1959), observes consists of the spoken word or words (hua) and of “the head or source” (tou). That is, a huatou–such as Wu or “Who?”–is a supreme, supremely charged, talismanic-like pointer, one that points immediately the source beyond words. Poetically put, the huatou’s immediate aim is to place one right at the doorstep of God–and to plant one right here.

Concerning the nature of the huatou, Chan master Gaofeng Yuanmiao (1238–1295) has powerfully commented:

[O]ne should act like a stone dropping into the deepest part of the pool–ten thousand feet deep–continuously and persistently dropping without interruption toward the bottom. If one can practice like this without stopping, continuously for seven days and still be unable to cut off one’s wandering, illusory thoughts and vexations, may I, Gaofeng, plunge into Avici Hell and stay there forever.

The huatou carries a kind of tension or torsion. Intellectually, it’s understood that you are Wu, yet, here and now, the Wu still feels so close yet just out of reach. That is, the Wu is you–and yet it’s still treated like a subtle it.

This tension, torsion, or wobble is a call to make oneself into a stone that keeps dropping deeper and deeper until one arrives at the bottom.

So long as there’s a hint of duality, drop deeper still. So long as there isn’t (yet) concentration on only THIS, sink deeper.

What’s at the bottom? Who is at the bottom? Who is the bottom? The Great Matter, so near, so precious, is not yet resolved. The Wu, thus, character becomes more and more captivating, more wondrous, or more doubtful until–until–Ah!