Braille Distribution: Or, Just Which Pins Take The Most Abuse In a Braille Reader?

It seems a simple question: which patterns/letters are the most common in Braille?

However, it’s not quite so simple, since Braille is not a straight character-for-character representation. For example, capital letters require another character in front, and Grade 2 Braille includes many contractions that use previously unused cells from Grade 1 Braille.

So, to do a very informal test, I entered some web text into the online from at MathsIsFun.com (actually, the text contents of that page!), and gathered the output in Grade 2 Braille, then wrote a program to count things: which characters were use and how often.

The result is not a big surprise, since the space is by far the most common character – here’s the table in Braille DOTS pin format and ASCII, as well as ranking (which is the direct entry in the Unicode 0x2800 Braille code page):

Position ASCII Code DOTS Format Count Position ASCII Code DOTS Format Count
0 SPACE 171 18 3 (2+5) 4
30 t (2+3+4+5) 50 19 h (1+2+5) 4
1 a (1) 44 38 8 (2+3+6) 4
17 e (1+5) 43 45 x (1+3+4+6) 4
14 s (2+3+4) 42 52 0 (3+5+6) 4
32 , (6) 42 57 ? (1+4+5+6) 4
21 o (1+3+5) 40 58 w (2+4+5+6) 4
23 r (1+2+3+5) 30 63 = (1+2+3+4+5+6) 4
7 l (1+2+3) 28 5 k (1+3) 3
29 n (1+3+4+5) 25 33 * (1+6) 3
10 i (2+4) 24 34 5 (2+6) 3
9 c (1+4) 22 51 (1+2+5+6) 3
15 p (1+2+3+4) 20 55 ( (1+2+3+5+6) 3
25 d (1+4+5) 20 22 6 (2+3+5) 2
61 y (1+3+4+5+6) 17 53 z (1+3+5+6) 2
37 u (1+3+6) 14 6 2 (2+3) 1
13 m (1+3+4) 13 24 ^ (4+5) 1
46 ! (2+3+4+6) 13 28 > (3+4+5) 1
2 1 (2) 12 35 < (1+2+6) 1
3 b (1+2) 12 39 v (1+2+3+6) 1
11 f (1+2+4) 12 40 . (4+6) 1
50 4 (2+5+6) 12 41 % (1+4+6) 1
27 g (1+2+4+5) 11 42 [ (2+4+6) 1
20 9 (3+5) 10 49 : (1+5+6) 1
47 & (1+2+3+4+6) 7 4 (3) 0
59 ] (1+2+4+5+6) 7 8 @ (4) 0
16 (5) 6 26 j (2+4+5) 0
36 (3+6) 6 31 q (1+2+3+4+5) 0
44 + (3+4+6) 6 43 $ (1+2+4+6) 0
54 7 (2+3+5+6) 5 48 ; (5+6) 0
60 # (3+4+5+6) 5 56 _ (4+5+6) 0
12 / (3+4) 4 62 ) (2+3+4+5+6) 0

The results come close to the distribution in English of letters, which is (roughly) “eitsanhurdmwgvlfbkopjxczyq” – but one big difference is the comma, which is actually the ASCII representation of the capitalization symbol (to make it even more complicated, apparently British Braille does not include it, which would skew the results).

Put together, it does give an idea of wear and tear on specific cells (say, for example, a daisywheel style Braille embosser). But another way to look at it is the individual ‘pins’ in a display: based on this sample, here’s how often each pin/dot gets used:

Braille Pin Counts In Sample
Pin 1: 399 times
Pin 2: 320 times
Pin 3: 364 times
Pin 4: 319 times
Pin 5: 318 times
Pin 6: 178 times

Good news: wear and tear is more or less evenly distibuted, except for pin 6, which is used about 50% as often as the others. Except for that, the result does means that a Braille display gets roughly even wear/usage across the pins – important for designers.

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