Where is the work of Chan to be done? The horse runs wild, the ape turns somersaults — cut them down, and quickly.

The chapter opens cold, on a poem, with nobody introducing it. That is unusual enough to be worth noticing: most chapters begin with a storyteller clearing his throat. Here four lines of instruction arrive first, and the story starts afterwards. The second line is the novel's oldest image of itself. 馬劣猿顛 sets a bad horse against a lurching ape, and behind it stands 心猿 and its partner the will-horse — the mind that will not sit still and the desire that bolts. Modern Chinese still says 心猿意馬 of somebody who cannot concentrate, and English borrowed the same picture as "monkey mind." The poem is telling you what the chapter is about before a single character walks on: the pilgrims are going to be undone by their own appetite for a good time.

Bind them fast, tether them tight, and the five colours are born; pause a moment, rest a moment, and you fall into the three paths.

Two halves that mirror each other exactly, and the mirroring is the argument. Hold on and you gain; let go and you lose. 五彩, the five colours, is what refined spirit is supposed to look like in Daoist inner alchemy — the sign that the work is taking. Against it, 三途, the three evil paths of Buddhist cosmology: rebirth as an animal, as a hungry ghost, or in hell. The two systems are set in one couplet — a matched pair of lines — without a word of apology, which is how this novel always works. Note how little slack the line allows — not idleness, just 暫停暫住, a pause, a rest. A fortnight off is enough.

Let the divine elixir leak away as it pleases, and the moment you relax, the jade nature withers.

The elixir here is the 神丹, and in inner alchemy it is not something you drink but something you grow, inside your own body, over years. Which is why the verb is 漏, to leak — the danger is not that somebody steals it, but that you let it seep out through inattention. 玉性, the jade nature, is the polished self that leaking ruins. And 從容 is the sting: it normally means unhurried, composed, the demeanour of somebody with themselves well in hand. Here it is a fault. Take your ease and the thing you built dries up.

Joy, anger, worry and brooding must all be swept clean; attain the mystery, attain the marvel, and it is exactly as if there were nothing at all.

掃淨, swept clean, is a word to hold on to. Within a few pages Tripitaka will insist on sweeping a pagoda, floor by floor, in his cassock — the poem's metaphor turned into an afternoon's work, and the novel does not point at the join. The last line is the payoff and it is deliberately anticlimactic: do all this and you arrive at 恰如無, exactly as if there were nothing. Not a reward, not a vision. The whole of the effort lands on an absence — which is the point, because what is being described is a mind with nothing left in it to disturb.