What Is Braille?
Braille is a tactile writing system used by people who are visually impaired. It was invented by Louis Braille in 1824, when he was just 15 years old, at the Royal Institute for Blind Youth in Paris. Unlike ciphers that hide the meaning of a message, Braille is an encoding system designed for accessibility — it translates printed text into a form that can be read by touch.
Each Braille character, called a cell, consists of up to six raised dots arranged in a 2-column by 3-row grid. The dots are numbered 1-2-3 down the left column and 4-5-6 down the right column. With six positions that can each be raised or flat, there are 2^6 = 64 possible combinations, which is sufficient for letters, numbers, punctuation, and special indicators.
How Braille Encoding Works
The Decade System
Louis Braille organized letters into systematic groups called decades:
- Decade 1 (A-J): Uses only dots 1, 2, 4, and 5 (top four positions)
- Decade 2 (K-T): Adds dot 3 to each Decade 1 pattern
- Decade 3 (U-Z): Adds dots 3 and 6 to Decade 1 patterns
The letter W was not part of the original French alphabet when Braille designed the system, so it received a unique pattern (dots 2, 4, 5, 6) that breaks the decade rule.
Special Indicators
Braille uses modifier cells to change how subsequent cells are interpreted:
| Indicator | Dots | Purpose |
|---|---|---|
| Capital indicator | Dot 6 | Next letter is uppercase |
| Number indicator | Dots 3, 4, 5, 6 | Following cells are digits (using A-J patterns) |
| Letter indicator | Dots 5, 6 | Return to letter mode after numbers |
Numbers in Braille
Numbers reuse the same dot patterns as the first ten letters (A=1, B=2, ... I=9, J=0), preceded by the number indicator. For example, the number "42" is encoded as: number indicator + D (for 4) + B (for 2).
How to Convert Text to Braille
- Break the text into characters — process each letter, number, space, or punctuation mark individually
- Add indicators — insert capital indicators before uppercase letters and number indicators before digit sequences
- Map to dot patterns — look up each character's dot combination in the Braille alphabet
- Generate output — convert dot patterns to Unicode Braille characters (U+2800 to U+28FF) or visual representations
Unicode Braille
The Unicode standard includes a dedicated block for Braille patterns (U+2800 to U+28FF). Each character's code point is calculated using the formula:
Code point = 0x2800 + (dot1 x 1) + (dot2 x 2) + (dot3 x 4) + (dot4 x 8) + (dot5 x 16) + (dot6 x 32)
This allows Braille to be represented in any Unicode-compatible text system, making it possible to share Braille text in emails, documents, and web pages.
Historical Context
Braille was inspired by Charles Barbier's "night writing" — a military code that used 12 dots to allow soldiers to communicate silently in the dark. Young Louis Braille found this system impractical because a 12-dot cell was too large to feel under a single fingertip. His genius was reducing it to 6 dots while maintaining enough combinations for a complete writing system.
The system was not widely adopted during Braille's lifetime. He died of tuberculosis in 1852 at age 43. It was only after his death that Braille became the international standard for tactile literacy. Today, Braille has been adapted for virtually every written language in the world, including mathematical notation (Nemeth code) and music (Braille music notation).