Void

Ku, the void, emptiness or heaven, is the fifth and highest of the Godai, the five elements of Japanese esoteric Buddhism, and it differs in kind from the four below it: rather than a material principle it is the element of spirit, sky and the formless, the emptiness that is not mere nothing but the pregnant void from which form arises and to which it returns, close to the Buddhist notion of sunyata, emptiness. In the gorinto, the five-ring stone pagoda, the void is the jewel or flame-shaped form at the very top, crowning earth, water, fire and wind.

The five came to Japan through esoteric Buddhism from India by way of China, systematised in the Shingon school. Miyamoto Musashi ended his Book of Five Rings with a short, elusive chapter on the void, the state beyond technique. The Godai are an old and living tradition, and the void as their summit, the formless ground of the elements, descends from the Buddhist teaching rather than from any modern esoteric construction.

In the gorinto, the five ring stupa raised across Japanese Buddhist grounds since the Heian period, Ku, void, caps the structure as its fifth and topmost tier: a jewel or flame shaped finial set above Fu's crescent, differing in kind from the four solids beneath it just as the element itself is said to differ from the four material elements it sits above. In the bodily mapping used in Shingon meditation on the gorinto, Ku corresponds to the crown, the point where the individual form opens onto what the tradition holds to be beyond form altogether.

No fixed shape captures Ku as directly as the cube, sphere, triangle and crescent capture the four beneath it, and ritual visualisation of its seed syllable is correspondingly described as an opening toward emptiness rather than a concrete image, consistent with Ku's identification with the sky, spirit and creative potential rather than a material substance.

Miyamoto Musashi closed his seventeenth century Book of Five Rings with a Void chapter shorter than the rest, using it not to add a fifth technique but to describe the state beyond technique, where a master acts without conscious calculation, a reading of Ku as the culmination the other four elements build toward rather than one more category alongside them.