Siddham Kha 𑖏

Kha is the aspirate of the velar class, a k released with a following breath, and it occupies the second slot of the first group of five. Its relationship to the letter before it is one of a single feature: same point of articulation, same voicelessness, breath added. Every one of the five classes has a letter in the same relationship to its own head, and that regularity is the whole design of the grid.

In the vocabulary the letter is not especially frequent. Sanskrit uses aspirated voiceless stops less than their plain partners across the board, and the velar aspirate is no exception, so a scribe writes it far less often than the letter it is paired with. Its place in the table is fixed by structure rather than by use, as with several letters of the syllabary.

Its importance in East Asia comes from elsewhere entirely. The syllable kha stands last in the set of five seed syllables assigned to the five elements, where it carries space, the most inclusive of the five and the one that contains the others. That places the letter at the top of every five-tiered stupa in Japan, which is a considerable presence for a character that a page of Sanskrit prose might not use at all.

The gap between the place of this letter in the language and its place in the tradition is unusually wide. Counted by how often a scribe writes it, kha is minor. Counted by how often it is cut into stone in Japan, it is among the most reproduced characters of the script. Both are true of the same letter and they belong to two different histories.

East Asian esoteric Buddhism works with a set of five elements, earth, water, fire, wind and space, and assigns to each a Siddham syllable: a, va, ra, ha and kha in that order. The set is compact, memorable and endlessly reproducible, and it is the single most visible use of the script in Japan.

Its standard form is the gorinto, a stone pagoda of five stacked shapes, a cube at the bottom, then a sphere, a pyramid, a half-moon and a jewel-shaped finial, each shape belonging to one element and each carrying that element's syllable. The same scheme is cut into wooden grave tablets, drawn on ritual objects and used in the layout of images. Once the sequence is known the monument reads at a glance, from the ground upward, earth to space.

Two things about the set are worth noticing. It is a set of five syllables and not a set of five letters: each is a Siddham character, and the whole is a scheme in which written sign, element, shape and position in a stack all correspond. And it is a scheme the atlas can describe from the outside, because the monuments are public and their reading is documented, while the practices the syllables belong to inside the two Japanese esoteric schools are transmitted under initiation and are not the atlas to set out. What is on the stone is a fact about the stone. What is done with it is not the atlas to say.