Tally mark five

It means five, counted the tally way. You draw one stroke per item; when four stand side by side, the fifth goes across them, diagonally or straight, and closes the bundle. Then you start a new one. In British English the shape is called a five-bar gate, because it looks like a field gate.

The trick is that bundles of five are easy to total at a glance: three gates and two loose strokes is seventeen, no recounting needed. That is why tallies survive on scoreboards, in classrooms, at vote counts, in bird surveys and on the proverbial prison-cell wall.

Not every country draws the same bundle. In China, Japan and Korea people write the character 正 one stroke at a time, since it has exactly five strokes; Unicode encodes that system separately, with 𝍶 as its five.

How do you write a full count with it?

Repeat 𝍸 for each five, then add 𝍷 for leftovers. Twelve is 𝍸𝍸𝍷𝍷. Unicode has only these two Western tally marks, one stroke and the complete five, so the in-between counts are built from single strokes. Because few fonts include them, check that your reader will see them before you rely on them; plain |||| and a slash is the safe fallback.