Go Rin No Sho was constructed — five scrolls, ordered, with an architecture that took two years in a cave. The letter was written to somebody. It has no architecture, because letters do not.
The movements, roughly in the order they appear:
無明住地煩悩 — the affliction of abiding in the place of ignorance. The name of the problem. 住 jū: to dwell, to reside, to stop on a thing.
諸仏不動智 — the immovable wisdom of all the buddhas. 不動明王 Fudō Myōō, with the sword and the rope, wreathed in fire — and the insistence that immovable does not mean unmoving. Fudō does not fail to move; he fails to stop.
間不容髪 — not a hair's breadth between. The interval, and the fact that it must not exist.
石火之機 — the spark-stone. No gap between the situation and the response. Not speed: the absence of a stop.
心の置き所 — where to put the mind. The section that answers itself by removing the question. Put it in the hands and it is in the hands; put it nowhere and it is everywhere.
本心・妄心 — the original mind and the deluded mind.
有心・無心 — the mind that is present and the mind of no-mind.
水上打胡蘆子・捺著即転 — pressing a gourd on water: it turns and goes, and cannot be pinned.
放心を放て — practical instruction, in a register close to advice.
急水上打球子 — a ball on a fast stream, which does not stop.
前後際断 — cutting off before and after.
It ends, as such letters do, without ceremony.