Braille pattern 12458

Four dots form a square; the fifth sits at bottom right.

An eight-dot Braille cell has two columns of four positions. Read from top to bottom, the left column is numbered 1, 2, 3, 7 and the right column 4, 5, 6, 8. In ⢛, both top rows are filled, the third row is empty, and only the right position in the bottom row is filled.

Unicode records this arrangement, not its translation. Braille codes assign readings to patterns for particular languages and notations. To decode ⢛ in a passage, identify that code and read the surrounding cells; the dot numbers alone are not a word.

Why does Braille have an eight-dot form?

Two extra positions make room for more distinct patterns.

Braille is writing read by touch through raised dots. Its familiar six-dot cell has two columns of three positions. Eight-dot Braille adds a bottom position to each column, allowing 256 patterns instead of 64, including the empty cell. This is useful for representing characters in computing.

The underlying writing system grew from Charles Barbier’s raised-dot method, introduced to a Paris school for blind pupils in 1821. Louis Braille, a pupil there, developed a compact six-dot system by 1824. Braille also supports mathematics, science and music; these uses do not all require eight-dot cells.