Worldbuilding Notes | The Circle With a Piece Missing—Why Do Five Civilizations Draw the Same Mark?

(This is an amateur compilation. It represents no academic institution, and is offered as a story.)

The conclusion first: this is probably just coincidence. The circle is the simplest shape there is; everyone on earth can draw one, and drawing it badly, leaving a gap, is the most ordinary thing in the world.

But set five unrelated ancient civilizations side by side, and this "coincidence" puts a small chill down your back.

East

Some bronze mirrors of the late-Qing, early-Republic period carry a ring of ornament cast into the back. Most are closed auspicious patterns, but on a few of them that circle breaks deliberately for a short stretch—collectors call them gap mirrors, and nobody can say why that one piece has to be missing.

Not one of these mirrors came out of an excavation; all of them are heirloom pieces. The 9 whose dates can be verified fall between 1890 and 1920, run from 8 to 14 centimetres across, and plainly did not come from a single workshop. Casting men say it is a flaw from the mould, a reject; bring a loupe up to it, though, and both ends of the break have been ground, with a ring of fine spiral marks left around them.

West

In the alchemical manuscripts of medieval Europe a symbol called "the Unfinished Ring" appears again and again. Alchemists used it for "a transmutation not yet closed". The manuscripts do not explain why that ring must be left with a gap.

4 copies of it have been seen so far, spanning the 14th to the 16th century, in different hands, all of them drawn crooked, and only that gap sits on the same side in every one. On the margin of one, a later hand added a line in paler ink:

This ring must not be made whole. He who makes it whole loses its use.

Middle East

On old Persian astrolabes there is a stretch of the graduated scale that does not join up. The craftsmen had the skill to cut a perfect circle; on that one stretch, they chose to leave it empty.

A conservator once handled a batch of astrolabes from around the 10th century. The scale on the outer limb is supposed to run the full 360 degrees, yet on 3 of them it stops somewhere along the way, and the signature points to the same workshop. He meant to complete it, and then read, in the remarks column of a resale docket, the buyer's instruction: leave it as it is.

India

On certain old mandalas the outermost ring is not closed. Asked about it, practitioners give one line back: "Once the circle closes, the door closes." As to what door, nobody goes on to explain.

This strand is the hardest to trace, since a sand mandala is swept away as soon as it is finished. What can be compared are a few cloth paintings from the 19th century: on some the whole stretch is left blank, on others the two lines draw together and still miss each other by the width of a line. Converted to a clock face, the break falls in the same quarter every time.

Africa

On the foreheads of some West African ancestral masks a ring is carved with an opening in it. Elders of those peoples say it is "the seam the ancestors come in by". The seam cannot be closed.

These masks belong to several peoples whose languages are mutually unintelligible; the two farthest places lie more than 900 kilometres apart, and the wood dates more than 200 years apart. One anthropologist assembled them into a table of angles and called it a "passage" symbol developed independently by each people; on that table every gap leans to the same side, and in a footnote he writes that this column is, for now, without an explanation.

Five civilizations, thousands of kilometres and thousands of years apart, working in materials and processes with nothing in common: bronze has to be sand-cast, an astrolabe struck out notch by notch with a graver, a mask dug out of one solid block of wood. By rights they have nothing to do with one another.

And yet what they drew is the same circle with a piece missing. Even the position of the gap lines up.

The usual account is convergence: the right hand finishes a clockwise stroke down at the lower right, so that is where a drawn circle breaks. The account is cheap and it works, except that those masks were dug out from the outside inward with the left hand steadying the wood. Those who hold that the pattern travelled the Silk Road have been stopped once as well: the Persian astrolabes are 900 years older than the earliest of those mirrors, and where was the pattern for those 900 years?

What does any of this mean? Probably nothing at all. The human brain loves finding a rule inside a coincidence.

Only, when five civilizations that never corresponded all insist that the circle "may not be closed", all half-feel that if it closed something would be shut out, or shut in—wouldn't you want to ask too: were they each superstitious in their own way, or did they all remember one same thing that we have forgotten?